nicht validierte Studentenversion Factors controlling the mobility of both Arsenic and Uranium in groundwater

Size: px
Start display at page:

Download "nicht validierte Studentenversion Factors controlling the mobility of both Arsenic and Uranium in groundwater"

Transcription

1 Factors controlling the mobility of both Arsenic and Uranium in groundwater Florian Krämer Zusammenfassung: Uran und Arsen sind als Spurenelemente in der Erdkruste und auch im Grundwasser nachzuweisen. In Ausnahmefällen (z.b. anthropogene Beeinflussung, Lagerstätten) können die Konzentrationen aber enorme Größenordnungen annehmen. Der entscheidende Faktor, welcher die Mobilität beider Elemente beeinflusst, ist die Adsorption an verschiedenen Festphasen. Aufgrund der existierenden chemischen Bedingungen, wie Redoxpotential, ph-wert und der Konzentration anderer Ionen, welche in der flüssigen Phase vorliegen, kommt es zur Bildung verschiedener Uran- bzw. Arsenspezies, welche unterschiedlich stark, je nach Chemie des Grundwassers, adsorbiert werden. Abstract: Uranium and Arsenic could be found as trace elements in the earth s crust and in ground water. If there are extraordinary conditions (e.g. anthropogenic influence, deposits) the concentrations, will be much higher in order of magnitude. The most important factor controlling the mobility of both elements is adsorption on different solid phases. Based on the existing chemical conditions like the redoxpotential, ph-value and the concentration of other ions in the liquid phase, different species of Uranium and Arsenic are formed and will be adsorbed differently depending on ground water chemistry. 1 Introduction Ground water composition is ultimately derived from rock weathering. The geology, the existing soils and the climatic conditions of a certain area are important factors for making statements about the concentrations and about the transport behaviour of arsenic and uranium in ground water sources. Adsorption is the predominate mechanism controlling transport of both elements in many ground water systems. Average concentrations of Arsenic in ground water are 0, 5 5 µg/l. But potable ground water supplies in many countries (Bangladesh, India, Taiwan, and Mongolia) contain dissolved arsenic in excess of 10 µg/l. The primary source of arsenic is natural (derived from interactions between ground water and aquifer sediments) and not anthropogenic (WELCH & STOLLENWERK 2003). Long-term exposure to arsenic in drinking water has been implicated in a variety of health concerns including several types of cancer, cardiovascular disease, diabetes, Blackfoot disease and neurological effects. Methyl arsenic compounds have a high acute toxicity, which decreases during demethylation. Limiting values for arsenic are included in the TrinkwV (2001) with 10 µg/l, in WHO with 10 µg/l and in the US EPA also with 10 µg/l. Uranium is a radioactive element and is naturally occurring in ground and surface water. It s a heavy metal like Arsenic and has also a long-term toxicity. Although uranium is enriched in granites and gneiss, ground water from these host rocks often shows low to intermediate uranium concentrations, while some ground waters from sandstone and carbonate aquifers show elevated uranium concentrations up to some hundred mg/l without man made impact. (MERKEL & HASCHE-BERGER 2005). Considering the WHO (2004) recommendation for drinking water of 9 µg/l due to the chemical toxicity of uranium. The TrinkwV (2001) doesn t include a limiting value for uranium and the US EPA proposes a limiting value of 30 µg/l. The facts of toxicity of both elements and radioactive radiation of uranium are important issues in environmental research and for human health care. Therefore it s important to do research in chemical behavior of both elements to minimize risks for environment and human health.

2 2 Aqueous chemistry 2.1 Arsenic speciation Dissolved arsenic speciation is important in determining the extent of reaction with the solid phase and therefore the mobility of Arsenic in ground water. Arsenic is generally present as arsenate [As(V)] or arsenite [As(III)] for Eh conditions prevalent in most ground waters (Fig. 1). Arsenic metal rarely occurs, and the -3 oxidation state is only found in very reducing environmental conditions. As (III) has been considered to be the more toxic oxidation state (WELCH & STOLLENWERK 2003) however, more recent studies have shown that most ingested As (V) can be reduced to As (III). Thus, exposure to both forms of As may result in similar toxicological effects (WELCH & STOLLENWERK 2003). Fig. 1: The Eh-pH diagramm for As at 25 C and one atmosphere with total arsenic 10-5 mol/l and total Sulfur 10-3 mol/l. Solid species are enclosed in parentheses in cross-hatched area, which indicates solubility less than mol/l (WELCH & STOLLENBERG 2003). Both As(III) and As(V) form protonated oxyanions in aqueous solutions, the degree of protonation depends on ph. Arsenate is stable is stable in oxidizing environments. For ph values common in groundwater, the predominant As(V) species in solution are H 2 AsO 4 - between ph 2.2 and 6.9 and HAsO 4-2 between ph 6.9 and 11.5.The solution concentration of H 2 AsO 4 - in soil is controlled primarily by adsorption reactions on oxides and hydroxides of Al, Fe, and Mn. Arsenite is stable in moderately reducing environments. H 3 AsO 3 0 predominates up to ph 9.2 and H 3 AsO 3 - from ph (WELCH & STOLLENBERG 2003). Methylated Species of As(III) and As(V) can be formed by biomethylation and anthropogenic impact. These species are stable under oxidizing and reducing conditions. 2.2 Uranium speciation As the most abundant actinide element, uranium averages 1.2 to 1.3 µg/g in sedimentary rocks, ranges from 2.2 to 15 µg/g in granites, and from 20 to 120 µg/g in phosphate rocks (LANGMUIR 1997). Ground waters in granite have some of the highest uranium concentrations, although they rarely exceed 20 µg/l. Uranium occurs in 4+, 5+ and 6+ oxidation states, which are usually written U(IV), U(V) and U(VI). Most important in nature are uranous [U(IV)] and uranyl [U(VI)] oxidation states. Uranous ion (U 4+ ) and its aqueous complexes predominate in ground waters of low redoxpotential. U(IV) is the major oxidation state in the most common uranium ore minerals uraninite, pitchblende and coffinite. The U(IV) concentrations in ground water at low Eh are usually less than 10-8 M because of the extremely low solubilities of these solids. In the U(V)

3 oxidation state, uranium occurs as the UO 2 + ion which forms relatively weak complexes. This species is only found at intermediate oxidation potentials and low ph s and is unstable relative to U(IV) and U(VI). In oxidized surface- and ground water, uranium is transported as highly soluble uranyl ion (UO 2 2+ ) and forms different complexes depending on ph-value and redoxpotential (e.g. with sulphate-, phosphate-, carbonate- and fluorid ions) which are highly soluble (Fig 2.) An Eh-pH diagram for the system U-O 2 -H 2 O at 25 C and a typical ground water uranium concentration of ΣU(aq) = 10-8 M is given in Fig. 2. The plot shows the stability fields of the dominant aqueous species and the large size of the stability field of uraninite [UO 2 (c)]. If instead the stability field of UO 2 (am) is plotted, it almost exactly overlaps the field of U(OH) 4. The diagram shows the predominance of the uranyl-hydroxy complexes at low Eh values in the presence of uraninite, with U(OH) 4 0 only important in waters where the Eh is less than about -100 to -200 mv. At a typical ground water CO 2 pressure of 10-2 bar, the highly stable uranyl carbonate complexes predominate above about ph 5 (Fig. 2). It shows that these complexes are stable relative to U(OH) 4 0 under highly reducing conditions. Accordingly above ph 5, the oxidation of U(IV)(aq) and dissolution of UO 2 (s) can occur at lower Eh values when high carbonate concentrations are present. Fig. 2: The Eh-pH diagramm for U at 25 C and one atmosphere with total uranium 10-8 mol/l. (a) system U-O 2 -H 2 O; (b) system U-O 2 -CO 2 -H 2 O at PCO 2 = 10-2 bar. UC = [UO 2 CO 3 ] 0, UDC = [UO 2 (CO 3 ) 3 ] -2 2, -4 UTC =[UO 2 (CO 3 ) 3 ] 3 (LANGMUIR 1997). 3 Adsorption/Desorption of arsenic 3.1 Mechanism Oxides of iron, aluminum (Al) and manganese are potentially the most important source/sink for As in aquifer sediments because of their chemistry, widespread occurrence and tendency to coat other particles. There are two widely accepted mechanisms for adsorption of solutes by a solid surface. Outer-sphere surface complexation or non-specific adsorption involves the electrostatic attraction between a charged surface and an oppositely charged ion in solution. The adsorbed ion resides at a certain distance from the mineral surface. Inner-sphere complexation, also termed specific adsorption, involves the formation of a coordinative complex with the mineral surface. Inner-sphere complex bonds are more difficult to break than outer-sphere complex bonds and result in stronger adsorption of ions.

4 3.2 ph value Fig. 3: Effect of ph value on As(V) adsorption (WILLIAMS ET AL. 2003). Arsenate is primarily adsorbed at low ph values. From ph 3 to 7 the percentage of As(V) adsorbed decreases slightly from approximately 95% to 85%. As the ph increases from 7 to 10 the percentage of As(V) adsorbed dropped dramatically, decreasing to approximately 40 to 50% between ph 9 and 10. This is typical of anion adsorption onto variably charged surfaces and results from the ühdependent surface charge and speciation of As(V). At lower ph values (ph < 7) As(V) exists predominantly as anion in the form H 2 AsO 4 - and is attracted to the positively charged soil surfaces (e.g. Fe oxides). At high ph values (ph > 7), As(V) exists as anion in the form H 2 AsO 4 2- and the oxide surfaces become increasingly negatively charged. This results in a decrease of As(V) adsorption with increasing ph (Fig. 3) 3.3 Clay minerals Results from experiments have shown that the adsorption per gram of solid of both As(III) and As(V) increased with initial solution concentration of As. Maximum adsorption of As(V) by kaolinite, montmorillonite, illite, halloysite and chlorite occurred up to ph 7, then decreased with further ph increases. Adsorption of As(III) by these same clay minerals was a minimum at low ph and increased with increasing ph. Arsenate adsorbed to a greater extent than As(III) on all clay minerals at ph < 7. At higher ph values, adsorption of As(V) and As (III) were more identical and in some cases As(III) adsorption exceeded that of As(V) (WELCH & STOLLENWERK 2003). Surface area can be an important factor in adsorption of As by clay minerals. Montmorillonite adsorbed about twice as much As(III) and As(V) as kaolinite. The surface area of montmorillonite was 2.5 times greater than kaolinte. Halloysite and chlorite were found to adsorb As(V) to a much greater extent than kaolinite, illite and montmorillonite. The reason of this fact is the greater surface area. But surface area is not always a good indicator of As(V) adsorption. E.g. kaolinite (9.1 m²/g) adsorbed 30 % more As(V) than illite (18.6 m²/g) and 50 % more than montmorillonite (24.2 m²/g). There are adsorption maximum for arsenate around ph 5 and for arsenite around ph 8-9 in contrast to its behaviour to oxides (Fig. 9). As(V) adsorption on clay minerals increases with increasing solution ph from 3 to 5 and decreases with increasing solution ph from 5 to 9. The renewed increase in arsenate adsorption observed when ph increased above ph 9 is most likely an artefact from dissolution of clay minerals at elevated ph. Adsorption affinity for As of the clay minerals is less than the adsorption affinity of the oxides. 100 % adsorption of As(V) was only reached by kaolinite around ph 5. For all other clay systems adsorption was significantly below 100 %, especially for arsenite. The competitive effect of the presence of equimolar concentrations of both As redox states is also shown in Fig. 4. The discrepancy in arsenate adsorption on Al oxide between the binary and the single ion system was the result of differences in amount of total As added. A competitive effect of the presence of arsenate on adsorption of arsenite was observed on kaolinite and illite (Fig. 4) in the intermediate ph range 6.5 to 9. No comparable competitive effect was observed for montmorillonite in the ph range 5 to 9. The apparent increase in arsenite adsorption below ph 5 resulted because of the oxidation of arsenite to arsenate (Fig. 4).

5 Fig. 4: Arsenic adsorption in kaolinite, montmorillonite and illite as a function of ph and redox state (GOLDBERG 2003). 3.4 Influence of competing ions Phosphate In addition to ph, the presence of other ions also affects the adsorption of As(V). One of the most significant of these ions is PO 4. Phosphate exhibits similar chemical behavior and is often used in fertilizers in agricultural areas where As may have been used as a pesticide or herbicide. However, it has been concluded that PO4 greatly enhanced the downward mobility of As(V) in soil columns.po 4 amended soils exhibited an increase in mobility of As relative to non-po 4 amended soils and noted the potentially important role of physical nonequilibrium on As(V) transport. In addition to time and As(V) concentration, several other parameters have been shown to influence As(V) adsorption, including ph, ionic strength, and the presence of competing anions will show the effect on adsorption of competing ions. The influence of phosphate on adsorption of As(V) and As(III) by ferrihydrite is a function of ph. Adsorption of both As(V) and As(III) decreased with increasing phosphate concentration. For As(V), the decrease was significant over the entire ph range. Phosphate has the greatest effect on As(III) adsorption at lower ph values. At ph 9, adsorption of As(III) decreased by only a few percent, even at the highest phosphate concentration. Apparently, the neutral H 3 AsO 3 0 was better able to compete for surface-complexation sites with HPO 4 - ² at higher ph. Phosphate competition with As(V) has been observed for other adsorbents. Experiments showed an 85 % decrease in As(V) adsorption by goethite when phosphate/as(v) ratio was increased from zero to 12:1. A phosphate/as(v) ratio of 1:1 caused a decrease of 30 % in As(V)adsorption by both goethite and gibbsite at ph < 8, compared to phosphate free solutions (Fig 8.) Similar effects of phosphate on As(V) adsorption were observed for kaolinite, montmorillonite and illite (MANNING & GOLDBERG 1997). Adding phosphate to natural systems has also been found to increase the mobility of As Carbonates There is evidence that carbonate minerals could be important in controlling the aqueous concentration of As, especially at higher ph values. Measurements showed that there is no adsorption of As(III) by CaCO 3 at ph 7. Adsorption of As(V) by calcite increased from a minimum of 0.7 mm/kg at ph 6 to a maximum of 2.0 mm/kg at ph 11. The effect of CO3 on As(V) adsorption was examined because carbonate is one of the most ubiquitous and important aqueous anions in the environment. The presence of CO3 decreased the extent of As(V) adsorption slightly.

6 3.4.3 Oxides of aluminum and iron The Al(III) atom has the same charge and a nearly identical radius as the Fe(III) atom. As a result, the common hydrous Al oxide phases are structurally similar to hydrous Fe oxides. They have also significant adsorption capacity for As, and their ph dependent adsorption isotherms are similar to those for Fe oxides and hydroxides. As, CH 3 AsO(OH) 2 0 and (CH 3 ) 2 AsOOH 0 were strongly adsorbed up to ph about 7 by amorphous Al(OH) 3, crystalline AL(OH) 3 (gibbsite), α- Al 2 O 3 and γ-al 2 O 3. Adsorption significantly decreased at higher ph values. Fig. 5: Adsorption of As on amorphous Al oxide as a function of ph and As redoxstate (GOLDBERG 2002). As(III) adsorption increased from ph 3 to a maximum at ph 8 then decreased at higher ph values (Fig. 5). 100 % of As(V) is adsorbed from ph 3-9 and then decreases with increasing solution ph. In all done experiments, the amount of adsorption As species increased as initial aqueous concentration increased until sites become saturated. Experiments that compared As adsorption by Fe and Al minerals showed that there is a slightly higher adsorption of As(V) by hydrous Fe oxide than hydrous Al oxide at ph values of 5-8. Fig. 6: Adsorption of As on amorphous Fe oxide as a function of ph and As redoxstate (GOLDBERG 2002). As(V) adsorption on amorphous Fe oxide shows 100 % adsorption from ph 3 to ph 7 and decreasing adsorption with increasing ph above ph 8. In contrast to its behaviour on Al oxide, arsenite adsorption on Fe oxide was virtually 100% throughout the entire ph range from ph 2.5 to ph 10.5 (Fig. 6). Thus it appears that amorphous Fe oxide had a grater affinity for adsorption of arsenite than amorphous Al oxide.

7 3.5 Organic compounds Organic compounds such as humic acid can adsorb on aquifer material or be present in aquifers as a result of depositional history. These compounds contain surface functional groups which can adsorb ions from solution (WELCH & STOLLENWERK 2003). Adsorption of As by two humic acids is a function of ph, As speciation and the humic acid composition. Experiments have shown that the adsorption of As(V) was slightly greater than As(III). However, the ph effect differed with humic acid composition. Arsenate and arsenite adsorption is differently depending on ash and Ca content. As(V) has a maximum at ph 6, whereas As(III) adsorption has a maximum at ph 8.5. Humic acids with lower ash and Ca content, both As(V) and As(III) exhibited broad adsorption maxima between ph 5.5 and Factors controlling adsorption/desorption of uranium 4.1 ph value Despite the influence of ionic strength on adsorption, (Fig. 11) shows the effects of ph at a constant ionic strength of 0.1 M. At low ph values, the adsorption of U(VI) approximately zero. The adsorption increases rapidly with ph over a relative narrow ph range of 4.5 to 5.5. With increasing ph the adsorption decreases also over a narrow ph range of 7.5 to 8.5. The reason for this could be the increase in the dissolved carbonate concentration with ph at constant carbon dioxide partial pressure or a concurrent increase in the concentration of U(VI)-carbonate complexes. There are three ph regions where carbonate exhibits different effects on U(VI) adsorption. The first ph region is at ph<5.0, the second region is between 5.0<pH<8.0, and the third region is at ph >8.0. At ph <5.0, carbonate does not have a negative effect on U(VI) adsorption on iron hydroxides. There is similar U(VI) adsorption behavior in the presence of carbonate at low ph. When ph is between 5.0 and 8.0, aqueous U(VI) is present as uranyl monocarbonate, uranyl dicarbonate, and uranyl tricarbonate. As total carbonate concentration increased, aqueous multicarbonate U(VI) complexes became more predominant and started forming at lower. Furthermore, carbonate attains maximum adsorption at ph 5.5. The reduced U(VI) adsorption could be attributed to the low affinity of uranium(vi) carbonate complexes to the surface sites and the competitive adsorption of carbonate on the surface. In the third region at ph>8.0, carbonate does not adsorb to the iron hydroxides and thus does not compete for the adsorption sites but rather competes with the surface to complex U(VI) as aqueous uranyl tricarbonate. At ph >8.0 and in the presence of carbonate, uranium(vi) tricarbonate is the predominant aqueous complex which prevents the adsorption of U(VI). 4.2 Clay minerals/humic acids Batch experiments for kaolinite and U(VI) are shown in Fig. 7. Fig. 7: Adsorption of U(VI) from solution as a function of ph and U(VI) concentration in the a) presence and b) absence of CO 2 (KREPELOVA, SACHS & BERNHARD 2006) In the presence of CO 2, the percentage of the total U(VI) adsorbed onto kaolinite increases from nearly zero at ph 3 to 97% between ph 6 and ph 8. Above ph 8, the U(VI) sorption decreases. The highest U(VI) adsorption occurs in the ph range, where the U(VI) hydroxyl complexes are important. The low adsorption rate at low ph values suggests the formation of relative strong inner-sphere complexes. The U(VI) sorption with and without CO 2 is comparable in the ph range between ph 3 and ph 8.

8 At ph > 8, however, no sorption decrease was observed in the absence of CO 2. This behavouir is a result of U(VI) speciation in the solution. In the presence of CO 2, U(VI) forms negatively charged uranyl-carbonato complexes. (e.g. UO 2 (CO 3 ) 3 4- ). Under these conditions the kaolinite surface is also negatively charged. Therefore, the electrostatic repulsions between uranyl-carbonato complexes and kaolinite result in the low U(VI) adsorption in this ph range. An increase of U(VI) initial concentration from 10-6 M to 10-5 M causes a shift of the sorption ph edge by one ph unit to higher ph values. With a higher intial concentration more U (VI) is adsorbed in the maximum of sorption curves but in general the percentage of U(VI) adsorbed onto kaolinite decreases due to higher initial concentration of U(VI) (KREPELOVA, SACHS & BERNHARD 2006). Fig. 8: Adsorption of U(VI) from solution as a function of ph, humic acid (HA) and U(VI) concentration in the a) presence and b) absence of CO2 (KREPELOVA, SACHS & BERNHARD 2006). The presence of HA influences significantly the adsorption of U(VI) onto kaolinite in the entire studied ph range (Fig. 8). At ph < 5, an increase in the U(VI) uptake was observed compared with the HA-free system. HA is almost 100% adsorbed on kaolinite surface in this ph range. It was expected that HA plays a competitive role under these conditions and results in reduction of U(VI). But the adsorbed HA offers additional binding sites for U(VI), therefore the U(VI) can rise up. At ph 5, desorption of HA from the kaolinite surface starts and leads to a decrease of U(VI) adsorption until ph 8.5. At ph > 8.5 in the presence of CO 2, the sorption of U(VI) again increases in the presence of HA. As HA is nearly completely desorbed from kaolinite surface (10 % remain adsorbed at ph 8.5) instead of decreasing adsorption of U(VI), adsorption is enhanced. Without CO 2,there is no decrease of U(VI) adsorption in the presence of HA. That s why carbonate has to play an important role in U(VI) sorption onto kaolinite. It is possible that uranyl-carbonato-humate complexes are formed, which can interact with the kaolinte surface and therefore, enhance U(VI) sorption onto kaolinite in the presence of HA in alkaline ph region. A higher concentration of HA causes lower adsorption of U(VI) on the kaolinite surface (KREPELOVA, SACHS & BERNHARD 2006). 4.3 Iron hydroxides/carbonate Carbonate dramatically affects the adsorption of uranium (U(VI)) onto iron hydroxides and its mobility in the natural environment. The amount of adsorbed U(VI) decreased substantially with increasing carbonate concentrations. Several factors could contribute to the reduced capacity of iron hydroxides to adsorb U(VI) in the presence of carbonate. It is well known that carbonate adsorbs onto hydroxides surfaces. As a result, fewer adsorption surface sites become available to other adsorbates. Carbonate uptake on the hydroxides surfaces will also decrease the surface charge. Aqueous carbonate also forms strong U(VI) complexes, which will have low affinity for the surface sites. Overall, carbonate competes with U(VI) for the adsorption sites and it also competes with the surface sites to complex U(VI). There are three ph regions where carbonate exhibits different effects on U(VI) adsorption. The first ph region is at ph<5.0, the second region is between 5.0<pH<8.0, and the third region is at ph >8.0. At ph <5.0, carbonate does not have a negative effect on U(VI) adsorption on iron hydroxides. When ph is between 5.0 and 8.0, aqueous U(VI) is present as uranyl monocarbonate, uranyl dicarbonate, and uranyl tricarbonate. As total carbonate concentration increased, aqueous

9 multicarbonate U(VI) complexes became more predominant and started forming at lower ph. Furthermore, carbonate attains maximum adsorption at ph 5.5. The reduced U(VI) adsorption could be attributed to the low affinity of uranium(vi) carbonate complexes to the surface sites and the competitive adsorption of carbonate on the surface. In the third region at ph>8.0, carbonate does not adsorb to the iron hydroxides and thus does not compete for the adsorption sites but rather competes with the surface to complex U(VI) as aqueous uranyl tricarbonate. At ph >8.0 and in the presence of carbonate, uranium(vi) tricarbonate is the predominant aqueous complex which prevents the adsorption of U(VI) (WAZNE ET AL. 2003). 4.4 Iron oxyhydroxide/phosphate Phosphate strongly adsorbed to goethite, and the extent of adsorption decreased with increasing ph. The adsorption of U(VI) onto the surface of goethite in the absence of phosphate is shown in Fig. 15. The extent of U(VI) adsorbed was strongly dependent on solution ph. Below ph 4.0, at total Fe concentration of 3.15*10-4 M, almost all U(VI) remained in the aqueous phase. The percentage of U(VI) adsorbed increased sharply between ph 4 and ph 6, and more than 99% of the U(VI) was adsorbed above ph 6. The ph edge shifted to the left with an increase in total Fe concentration from 3.15*10-4 to 3.15*10-3 M, indicating more U(VI) adsorption at the same ph due to a higher concentration of available surface sites (CHENG ET AL. 2003). In the low ph range, the addition of phosphate greatly increased U(VI) adsorption. Higher phosphate concentration generally caused a greater effect (Fig. 9). Fig. 9: U(VI) adsorption on goethite in the absence of 5 Summary (CHENG ET AL. 2003). This table should show an over all overview about the main factors controlling the transport of uranium and arsenic in ground water. Tab. 1: Summary of controlling factors fort the mobility of arsenic factor redox conditions arsenic arsenite (As(III)) arsenate (As(V)) mobile under low Eh-conditions less adsorbed at oxides or hydroxides predominant under oxidizing conditions complexes are negatively

10 ph value clay minerals oxides competitive ions phosphate carbonate organic compounds (adsorption differs depending on humic acid composition) because of zero charge of the complex minimum adsorption under low ph high mobile and increasingly adsorbed at high ph values Low adsorption at low ph values but increases with increasing ph high adsorption from ph 3 to ph 8 then decreases at high ph values (Al oxides) more constant adsorption by iron oxide over the entire ph range Greatest effect at low ph values decreased adsorption No adsorption by CaCO 3 Higher adsorption maximum charged and adsorbed on surfaces low mobility adsorbed previously at low ph, mobile under high ph values highest adsorption up to ph 7 then decreasing mobile at ph > 7. Much more adsorbed than As(III) at ph < 7 adsorbed from ph 3-9 and then decreases with increasing solution ph (Aloxides) more adsorbed by iron oxides over the whole ph range Low adsorption over the entire ph range with increasing phosphate concentration Increased adsorption by Ca CaCO 3 from ph 6 to ph 11 higher adsorption than As(III) Tab. 2: Summary of controlling factors fort the mobility of uranium factor redox conditions uranium U(IV) low soluble under reducing conditions no transport, high adsorption (e.g. minerals) U(VI) mobile under oxidizing conditions low sorption of uranyl-carbonato complexes with

11 ph value high soluble under oxidizing conditions ph doesn t play an important role, because U(IV) is often quickly oxidized to U(VI). U(IV) is primarily bound in minerals increasing solubility of these complexes Higher ph values uranylcarbonato complexes with increasing solubility of these complexes Low ph: uranylion with high solubility and mobility clay minerals No data High adsorption from ph 4 untill ph 7 low mobility Higher initial concentration of U(VI) increases the adsorption oxyhydroxid No data High adsorption between ph 4 to 6 and over ph 6 Higher iron concentration increases U(VI) adsorption competitive ions carbonate No data Increasing carbonate concentration higher adsorption phosphate No data Increasing phosphate concentration higher adsorption of U(VI) at low ph values 6 Literature cited WELCH, A.H. & STOLLENWERK, K.G. (2003): Arsenic in Ground Water Geochemistry and Occurrence: P , P MERKEL, B. J. HASCHE-BERGER, A. (2005): Uranium in the environment: mining impact and consequences: P: XVII Preface LANGMUIR, D. (1997) Aqueous Environmental Geochemistry: P WILLIAMS, L. E., BARNETT, M.O., KRAMER, T. A. & MELVILLE, J. G. (2003): Adsorption and Transport of Arsenic(V) in Experimental Subsurface Systems In: Journal of Environmental Quality, Vol.32, P: MANNING, B. A. & GOLDBERG, S. (1997): Adsorption and Stability of Arsenic(III) at the Clay Mineral Water Interface In: Environmental Science & Technology (1997), Vol. 31, No. 7, P:

12 GOLDBER, S. (2002): Competitive Adsorption of Arsenate and Arsenite on Oxides and Clay Minerals In: Soil Science Society (2002), Vol. 66, P: KREPELOVÁ, A., SACHS, S. & BERNHARD, G. (2006): Uranium(VI) sorption onto kaolinite in the presence and absence of humic acid In: Radiochimica Acta (2006), Vol. 94, P: WAZNE, M., KOFIATIS, G. P. & MENG, X. (2003): Carbonate Effects on Hexavalent Uranium Adsorption by Iron Oxyhydroxide In: Environmental Science & Technology (2003), Vol. 37, P: CHENG, T., BARNETT, M. O., RODEN, E. E. & ZHUNG, J. (2004): Effects of Phosphate on Uranium(VI) Adsorption to Goethite-Coated Sand In: Environmental Science & Technology (2004), Vol. 38, P:

Potential Impacts of Tailings and Tailings Cover. Fertilization on Arsenic Mobility in Surface and. Ground Waters

Potential Impacts of Tailings and Tailings Cover. Fertilization on Arsenic Mobility in Surface and. Ground Waters Potential Impacts of Tailings and Tailings Cover Fertilization on Arsenic Mobility in Surface and Ground Waters Sierra Rayne * and Kaya Forest Water Treatment Technology Program, Thompson Rivers University,

More information

Sorption-Desorption at Colloid-Water Interface:

Sorption-Desorption at Colloid-Water Interface: Sorption-Desorption at Colloid-Water Interface: A Phenomenon of Environmental Significance Soil Chemical Processes and Ecosystem Health Soil is THE MOST IMPORTANT sink of contaminants Calculated equilibrium

More information

How Arsenic Chemistry Determines Remediation Efficacy as well as Fate and Transport Russ Gerads Business Development Director

How Arsenic Chemistry Determines Remediation Efficacy as well as Fate and Transport Russ Gerads Business Development Director Northwest Remediation Conference October 5, 2017 How Arsenic Chemistry Determines Remediation Efficacy as well as Fate and Transport Russ Gerads Business Development Director www.brooksapplied.com Arsenic

More information

Geochemical Investigation of Naturally Occurring Arsenic in Upper Midwest Ground Water

Geochemical Investigation of Naturally Occurring Arsenic in Upper Midwest Ground Water Geochemical Investigation of Naturally Occurring Arsenic in Upper Midwest Ground Water Mindy Erickson Minnesota Department of Transportation and University of Minnesota Water Resources Science Source vs.

More information

Chapter 7: Anion and molecular retention

Chapter 7: Anion and molecular retention I. Anions and molecules of importance in soils Anions of major importance to agricultural soils and soil chemistry are: H 2 PO - 4, HPO 2-4, SO 2-4, HCO - 3, NO - 3, Cl -, F - and OH -. Also, micronutrients

More information

Adsorption of Sb(V) on Goethite: Effect of ph, Ionic Strength, and Competition with Phosphate

Adsorption of Sb(V) on Goethite: Effect of ph, Ionic Strength, and Competition with Phosphate Adsorption of Sb(V) on Goethite: Effect of ph, Ionic Strength, and Competition with Phosphate Jianhong Xi Supervised by Liping Weng Outline General introduction Material and methods Experimental results

More information

Arsenic and Other Trace Elements in Groundwater in the Southern San Joaquin Valley of California

Arsenic and Other Trace Elements in Groundwater in the Southern San Joaquin Valley of California Arsenic and Other Trace Elements in Groundwater in the Southern San Joaquin Valley of California Dirk Baron Geological Sciences California State University, Bakersfield Trace Element Maximum Contaminant

More information

Surface Complexation.

Surface Complexation. Surface Complexation. Jean-François Gaillard, Notes for CE-367 OBJECTIVES To show how the presence of particles in natural and engineered systems controls the fate of many trace elements. The concepts

More information

12. Lead, Pb (atomic no. 82)

12. Lead, Pb (atomic no. 82) 12. Lead, Pb (atomic no. 82) - Sources of Pb contamination include mining, metal processing, lead battery manufacturing, chemical and paint manufacturing, and lead wastes. -USEPA drinking water action

More information

GEOCHEMISTRY, GROUNDWATER AND POLLUTION,

GEOCHEMISTRY, GROUNDWATER AND POLLUTION, GEOCHEMISTRY, GROUNDWATER AND POLLUTION, 2 ND EDITION C.A.J. APPELO Hydrochemical Consultant, Amsterdam, the Netherlands D. POSTMA Environment & Resources DTU, Technical University of Denmark, Kgs. Lyngby,

More information

CLASS EXERCISE 5.1 List processes occurring in soils that cause changes in the levels of ions.

CLASS EXERCISE 5.1 List processes occurring in soils that cause changes in the levels of ions. 5 SIL CHEMISTRY 5.1 Introduction A knowledge of the chemical composition of a soil is less useful than a knowledge of its component minerals and organic materials. These dictate the reactions that occur

More information

Copyright SOIL STRUCTURE and CLAY MINERALS

Copyright SOIL STRUCTURE and CLAY MINERALS SOIL STRUCTURE and CLAY MINERALS Soil Structure Structure of a soil may be defined as the mode of arrangement of soil grains relative to each other and the forces acting between them to hold them in their

More information

Don Macalady 2 and Dianne Ahmann 1, Principle Investigators

Don Macalady 2 and Dianne Ahmann 1, Principle Investigators Redox Transformations, Complexation and Soil/Sediment Interactions of Inorganic Forms of Arsenic and Selenium in Aquatic Environments: Effects of Natural rganic Matter Don Macalady 2 and Dianne Ahmann

More information

Adsorption of ions Ion exchange CEC& AEC Factors influencing ion

Adsorption of ions Ion exchange CEC& AEC Factors influencing ion Adsorption of ions Ion exchange CEC& AEC Factors influencing ion exchange- Significance. Adsorption of ions Ion adsorption and subsequent exchange are important processes that take place between soil colloidal

More information

Arsenic Removal by Graphene Oxide-Nanoscale Zero-valent Iron Hybrid

Arsenic Removal by Graphene Oxide-Nanoscale Zero-valent Iron Hybrid 6 th Sustainable Nanotechnology Conference,2017 Arsenic Removal by Graphene Oxide-Nanoscale Zero-valent Iron Hybrid Tonoy K Das Achintya N. Bezbaruah Nanoenvirology Research Group, Department of Civil

More information

Lecture 15: Adsorption; Soil Acidity

Lecture 15: Adsorption; Soil Acidity Lecture 15: Adsorption; Soil Acidity Surface Complexation (Your textbook calls this adsorption ) Surface Complexation Both cations and anions can bind to sites on the external surfaces of soil minerals

More information

The Sorption Properties of Humate Injected into the Subsurface System. Hansell Gonzalez Raymat DOE Fellow Graduate Student, Ph.D.

The Sorption Properties of Humate Injected into the Subsurface System. Hansell Gonzalez Raymat DOE Fellow Graduate Student, Ph.D. The Sorption Properties of Humate Injected into the Subsurface System Hansell Gonzalez Raymat DOE Fellow Graduate Student, Ph.D. in Chemistry Background Background Approximately 1.8 billion gallons of

More information

Geochemical study of arsenic release mechanisms in the Bengal Basin groundwater

Geochemical study of arsenic release mechanisms in the Bengal Basin groundwater Geochemical study of arsenic release mechanisms in the Bengal Basin groundwater Carolyn B. Dowling, Robert J. Poreda, Asish R. Basu, and Scott L. Peters Sampling Sixty-eight groundwater samples Bangladesh

More information

CHAPTER 3. BATCH STUDIES FOR As(III) REMOVAL FROM WATER BY USING MAGNETITE NANOPARTICLES COATED SAND: ADSORPTION KINETICS AND ISOTHERMS

CHAPTER 3. BATCH STUDIES FOR As(III) REMOVAL FROM WATER BY USING MAGNETITE NANOPARTICLES COATED SAND: ADSORPTION KINETICS AND ISOTHERMS CHAPTER 3 BATCH STUDIES FOR As(III) REMOVAL FROM WATER BY USING MAGNETITE NANOPARTICLES COATED SAND: ADSORPTION KINETICS AND ISOTHERMS 41 42 3.1. INTRODUCTION Arsenic contamination of ground water and

More information

Chapter 1. Introduction

Chapter 1. Introduction Introduction 1 Introduction Scope Numerous organic chemicals are introduced into the environment by natural (e.g. forest fires, volcanic activity, biological processes) and human activities (e.g. industrial

More information

Lecture 14: Cation Exchange and Surface Charging

Lecture 14: Cation Exchange and Surface Charging Lecture 14: Cation Exchange and Surface Charging Cation Exchange Cation Exchange Reactions Swapping of cations between hydrated clay interlayers and the soil solution Also occurs on organic matter functional

More information

Distribution of radionuclides in soils dependence on soil parameters

Distribution of radionuclides in soils dependence on soil parameters Landesmessstelle für Radioaktivität Fachbereich 01 Fachbereich Physik/Elektrotechnik Distribution of radionuclides in soils dependence on soil parameters BIOPROTA-Meeting Nancy 24.05.2012 Contents modelling

More information

The Geochemistry of Natural Waters

The Geochemistry of Natural Waters The Geochemistry of Natural Waters Surface and Groundwater Environments Third Edition James I. Drever University of Wyoming Prentice Hall Upper Saddle River. NJ 07458 Contents 3 Preface xi 1 The Hydrologie

More information

WM 04 Conference, February 29 March 4, 2004, Tucson AZ ESTIMATING SITE CONCENTRATIONS IN SOILS FOR SURFACE COMPLEXATION MODELING OF SORPTION

WM 04 Conference, February 29 March 4, 2004, Tucson AZ ESTIMATING SITE CONCENTRATIONS IN SOILS FOR SURFACE COMPLEXATION MODELING OF SORPTION ESTIMATING SITE CONCENTRATIONS IN SOILS FOR SURFACE COMPLEXATION MODELING OF SORPTION M. Ewanic, M. North-Abbott, D. Reichhardt, M. H. Zaluski MSE Technology Applications, Inc. ABSTRACT MSE Technology

More information

The make-up of a natural solution.

The make-up of a natural solution. The make-up of a natural solution http://eps.mcgill.ca/~courses/c220/ The make-up of a natural solution I Particulate or solids II- Colloidal material III Truly dissolved a) non-associated (free) b) associated

More information

Cation Exchange Capacity, CEC

Cation Exchange Capacity, CEC Cation Exchange Capacity, CEC The basic building blocks of clay minerals are: silicon atoms surrounded by four oxygen atoms (tetrahedra), and aluminium atoms surrounded by six hydroxide groups (dioctahedra),

More information

EXTRAPOLATION STUDIES ON ADSORPTION OF THORIUM AND URANIUM AT DIFFERENT SOLUTION COMPOSITIONS ON SOIL SEDIMENTS Syed Hakimi Sakuma

EXTRAPOLATION STUDIES ON ADSORPTION OF THORIUM AND URANIUM AT DIFFERENT SOLUTION COMPOSITIONS ON SOIL SEDIMENTS Syed Hakimi Sakuma EXTRAPOLATION STUDIES ON ADSORPTION OF THORIUM AND URANIUM AT DIFFERENT SOLUTION COMPOSITIONS ON SOIL SEDIMENTS Syed Hakimi Sakuma Malaysian Institute for Nuclear Technology Research (MINT), Bangi, 43000

More information

International Summer Water Resources Research School. Competitive adsorption of As(III) and As(V) on goethite By Erik Lidén

International Summer Water Resources Research School. Competitive adsorption of As(III) and As(V) on goethite By Erik Lidén International Summer Water Resources Research School Dept. of Water Resources Engineering, Lund University Competitive adsorption of and As(V) on goethite By 2011 Abstract Arsenic (As) is a semi-metal

More information

Microbially Enhanced Iron-Modified Zeolite Permeable Reactive Barrier

Microbially Enhanced Iron-Modified Zeolite Permeable Reactive Barrier Microbially Enhanced Iron-Modified Zeolite Permeable Reactive Barrier ERC Team Members CBBG Faculty Charalambos Papelis, NMSU Paola Bandini, NMSU Graduate Students Neda Halalsheh Audrey Smith Undergraduate

More information

1. Let s quickly review some of the phosphorus fixation reactions in soils. 2. At low ph (acidic conditons below 6.0), phosphorus fixation occurs

1. Let s quickly review some of the phosphorus fixation reactions in soils. 2. At low ph (acidic conditons below 6.0), phosphorus fixation occurs 1 1. Let s quickly review some of the phosphorus fixation reactions in soils. 2. At low ph (acidic conditons below 6.0), phosphorus fixation occurs between phosphates and iron or aluminum in the soil solution

More information

Geology 560, Prof. Thomas Johnson, Fall 2009 Class Notes: Unit III Part 2. Weak Acids- Speciation

Geology 560, Prof. Thomas Johnson, Fall 2009 Class Notes: Unit III Part 2. Weak Acids- Speciation Geology 560, Prof. Thomas Johnson, Fall 2009 Class Notes: Unit III Part 2. Weak Acids Speciation Reading: White 6.2; Walther Ch. 6 Sections on Acid/Base equilibria, buffers, and carbonate solubility We

More information

Wednesday April Arsenic in Groundwater: Chemistry and How to Address It. David J Silverman P.E. New York Region Applications Engineer

Wednesday April Arsenic in Groundwater: Chemistry and How to Address It. David J Silverman P.E. New York Region Applications Engineer Wednesday April 13 2016 Arsenic in Groundwater: Chemistry and How to Address It David J Silverman P.E. New York Region Applications Engineer Presentation Outline Arsenic- background information Arsenic

More information

Synthesis and Application of Manganese Dioxide Coated Magnetite for Removal of Trace Contaminants from Water. Carla Calderon, Wolfgang H.

Synthesis and Application of Manganese Dioxide Coated Magnetite for Removal of Trace Contaminants from Water. Carla Calderon, Wolfgang H. X 2008 Synthesis and Application of Manganese Dioxide Coated Magnetite for Removal of Trace Contaminants from Water Carla Calderon, Wolfgang H. Höll Institute for Technical Chemistry, Water and Geotechnology

More information

Acid Soil. Soil Acidity and ph

Acid Soil. Soil Acidity and ph Acid Soil Soil Acidity and ph ph ph = - log (H + ) H 2 O H + + OH - (H + ) x (OH - )= K w = 10-14 measures H + activity with an electrode (in the lab), solutions (in the field) reflects the acid intensity,

More information

REMOVAL OF ARSENIC, CHROMIUM AND LEAD FROM SIMULATED GROUNDWATER WITH REACTIVE NANOSCALE IRON PARTICLES

REMOVAL OF ARSENIC, CHROMIUM AND LEAD FROM SIMULATED GROUNDWATER WITH REACTIVE NANOSCALE IRON PARTICLES REMOVAL OF ARSENIC, CHROMIUM AND LEAD FROM SIMULATED GROUNDWATER WITH REACTIVE NANOSCALE IRON PARTICLES Kenji Okinaka (Kenji_Okinaka@todakogyo.co.jp) (Toda Kogyo Corporation, Yamaguchi, Japan) Andreas

More information

WEATHERING. Turning Rock to Sediment and Solutions 10/22/2012

WEATHERING. Turning Rock to Sediment and Solutions 10/22/2012 WEATHERING Turning Rock to Sediment and Solutions Igneous rocks form at high temperatures; at the Earth s surface they are chemically unstable and will begin to disintegrate and decompose in a process

More information

Weathering and Soils

Weathering and Soils OCN 401-11 Oct. 13, 2011 KCR Weathering and Soils Biogeochemistry Chapter 4: The Lithosphere Introduction: the context Rock Weathering Soil Chemical Reactions Soil Development (see text) Weathering Rates

More information

Shirley E. Clark, Ph.D., P.E., D. WRE Robert E. Pitt, Ph.D., P.E., BCEE, D. WRE

Shirley E. Clark, Ph.D., P.E., D. WRE Robert E. Pitt, Ph.D., P.E., BCEE, D. WRE Shirley E. Clark, Ph.D., P.E., D. WRE Robert E. Pitt, Ph.D., P.E., BCEE, D. WRE Current PA Guidance Many guidance documents apply expected pollutant removals based on literature. However, typically presented

More information

SOIL and WATER CHEMISTRY

SOIL and WATER CHEMISTRY SOIL and WATER CHEMISTRY An Integrative Approach MICHAEL E. ESSINGTON CRC PRESS Boca Raton London New York Washington, D.C. Table of Contents Chapter 1 The Soil Chemical Environment: An Overview 1 1.1

More information

Soil Colloidal Chemistry. Compiled and Edited by Dr. Syed Ismail, Marthwada Agril. University Parbhani,MS, India

Soil Colloidal Chemistry. Compiled and Edited by Dr. Syed Ismail, Marthwada Agril. University Parbhani,MS, India Soil Colloidal Chemistry Compiled and Edited by Dr. Syed Ismail, Marthwada Agril. University Parbhani,MS, India 1 The Colloidal Fraction Introduction What is a colloid? Why this is important in understanding

More information

Pamela Reilly and Julia Barringer

Pamela Reilly and Julia Barringer Pamela Reilly and Julia Barringer U.S. Geological Survey New Jersey Water Science Center This information is preliminary and is subject to revision. It is being provided to meet the need for timely best

More information

Env/CE 543 Aquatic Chemistry. Sample Midterm Exam

Env/CE 543 Aquatic Chemistry. Sample Midterm Exam Env/CE 543 Aquatic Chemistry Sample Midterm Exam Note: The questions on this exam were taken from previous midterm and final exams. This sample exam is about 1.5 to 2.0 times longer than the midterm exam

More information

Lecture 13 More Surface Reactions on Mineral Surfaces. & Intro to Soil Formation and Chemistry

Lecture 13 More Surface Reactions on Mineral Surfaces. & Intro to Soil Formation and Chemistry Lecture 13 More Surface Reactions on Mineral Surfaces & Intro to Soil Formation and Chemistry 3. charge transfer (e.g., ligand/donor sorption): Sorption involves a number of related processes that all

More information

Energy and Resources Recovery from Reverse Osmosis Desalination Concentrate

Energy and Resources Recovery from Reverse Osmosis Desalination Concentrate Energy and Resources Recovery from Reverse Osmosis Desalination Concentrate Tushar Jain; PhD advisor: Haizhou Liu Department of Chemical and Environmental Engineering, University of California, Riverside,

More information

Chemistry. Soil and Environmental. William F. Bleam. University of Wisconsin, Madison ELSEVIER AMSTERDAM BOSTON HEIDELBERG LONDON PARIS

Chemistry. Soil and Environmental. William F. Bleam. University of Wisconsin, Madison ELSEVIER AMSTERDAM BOSTON HEIDELBERG LONDON PARIS PARIS SAN Soil and Environmental Chemistry William F. Bleam University of Wisconsin, Madison AMSTERDAM BOSTON HEIDELBERG LONDON ELSEVIER NEW YORK OXFORD DIEGO SAN FRANCISCO SINGAPORE SYDNEY TOKYO Academic

More information

A few more details on clays, Soil Colloids and their properties. What expandable clays do to surface area. Smectite. Kaolinite.

A few more details on clays, Soil Colloids and their properties. What expandable clays do to surface area. Smectite. Kaolinite. A few more details on clays, Soil Colloids and their properties What expandable clays do to surface area Kaolinite Smectite Size 0.5-5 µm External surface 10-30 m 2 /g Internal surface - Size 0.1-1 µm

More information

North-West University, Private Bag X2046, Mmabatho 2735, South Africa. 2. *Corresponding author:

North-West University, Private Bag X2046, Mmabatho 2735, South Africa. 2. *Corresponding author: Re-mobilization of uranium and thorium from sediments contaminated by naturally occurring radioactive material (NORM) through leaching by acid mine drainage (AMD). Faanhof A 1, Shongwe NS 2 and Connell,

More information

Application of Fe 2 O 3 nanoparticles in Heavy Metal Removal

Application of Fe 2 O 3 nanoparticles in Heavy Metal Removal Application of Fe 2 O 3 nanoparticles in Heavy Metal Removal 5.1 Introduction Different contaminants are released to water bodies due to the rapid industrialization of human society, including heavy metal

More information

OPV s.r.o., Praha, Czech Republic. Córdoba, C

OPV s.r.o., Praha, Czech Republic. Córdoba, C Arsenic enrichment of ground water at two regions of the Chacopampean plain, northwest Argentina Ondra Sracek 1,2, María Gabriela GarcG arcía 3 1 OPV s.r.o., Praha, Czech Republic 2 Pontificia Universidade

More information

Distribution of radionuclides in soils modelling the dependence on soil parameters

Distribution of radionuclides in soils modelling the dependence on soil parameters Landesmessstelle für Radioaktivität Institut für Umweltphysik Fachbereich Physik/Elektrotechnik Distribution of radionuclides in soils modelling the dependence on soil parameters Volker Hormann and Helmut

More information

Weathering and Soils

Weathering and Soils OCN 401-17 Aug. 29, 2016 KCR Weathering and Soils Biogeochemistry Chapter 4: The Lithosphere Introduction: the context Rock Weathering Soil Chemical Reactions Soil Development (see text) Weathering Rates

More information

Lecture 1: RDCH 710 Introduction

Lecture 1: RDCH 710 Introduction Lecture 1: RDCH 710 Introduction Class organization Outcomes Grading Natural actinide species Th U Transuranic synthesis Lecture notes based on LANL radiochemistry course 1-1 Course overview The unique

More information

Redox, ph, pe OUTLINE 9/12/17. Equilibrium? Finish last lecture Mineral stability Aquatic chemistry oxidation and reduction: redox

Redox, ph, pe OUTLINE 9/12/17. Equilibrium? Finish last lecture Mineral stability Aquatic chemistry oxidation and reduction: redox Redox, ph, pe Equilibrium? OUTLINE Finish last lecture Mineral stability Aquatic chemistry oxidation and reduction: redox Reading: White p555-563 1 Question of the day? So what about the CO 2 system? CO

More information

PHOSPHATE ADSORPTION BY THE MIXED INORGANIC ION EXCHANGER BASED ON FE-MN HYDROUS OXIDES: EQUILIBRIUM AND FTIR STUDIES

PHOSPHATE ADSORPTION BY THE MIXED INORGANIC ION EXCHANGER BASED ON FE-MN HYDROUS OXIDES: EQUILIBRIUM AND FTIR STUDIES Proceedings of the 14 th International Conference on Environmental Science and Technology Rhodes, Greece, 35 September 2015 PHOSPHATE ADSORPTION BY THE MIXED INORGANIC ION EXCHANGER BASED ON FEMN HYDROUS

More information

The Influence of Humic Acid and Colloidal Silica on the Sorption of U(VI) onto SRS Sediments Collected from the F/H Area

The Influence of Humic Acid and Colloidal Silica on the Sorption of U(VI) onto SRS Sediments Collected from the F/H Area The Influence of Humic Acid and Colloidal Silica on the Sorption of U(VI) onto SRS Sediments Collected from the F/H Area - 15499 Hansell Gonzalez a, Yelena Katsenovich a *, Miles Denham b, Ravi Gudavalli

More information

Green rust articles (key and from the consortium marked with *)

Green rust articles (key and from the consortium marked with *) Green rust articles (key and from the consortium marked with *) Stability, structure, formation and transformation Hansen et (1989) Composition, stabilization, and light absorption of Fe(II)Fe(III) hydroxy-carbonate

More information

Gain a better understanding of soil ph and how it is measured. Understand how lime requirement is determined.

Gain a better understanding of soil ph and how it is measured. Understand how lime requirement is determined. LABORATORY 7 SOIL REACTION (ph) AND LIME REQUIREMENT I Objectives Gain a better understanding of soil ph and how it is measured. Understand how lime requirement is determined. II Introduction A Soil Reaction

More information

Effect of Humic Acid on the Selenite Adsorption onto Hematite

Effect of Humic Acid on the Selenite Adsorption onto Hematite Effect of Humic Acid on the Selenite Adsorption onto Hematite MYOUNG-JIN KIM, MIJEONG JANG, and SE YOUNG PAK Department of Environmental Engineering Korea Maritime University 1, Dongsam-dong, Yeongdo-gu,

More information

Subject Index. Darcy's law 213 deformation 235 demethylation 148,155,156,157,158,159 desmetryn 70,71

Subject Index. Darcy's law 213 deformation 235 demethylation 148,155,156,157,158,159 desmetryn 70,71 acid mine drainage 149 acidic polysaccharides 58 acidification 148,149,166 acidity 62 absorption 4, 5 adsorption 4,5,38,62, 63, 65, 66, 68, 70,71,73,77, 102, 104 free energy of 78 energy 79 Al 95 Al oxide

More information

Adsorption of Humic acid on Powdered Activated Carbon (PAC)

Adsorption of Humic acid on Powdered Activated Carbon (PAC) Adsorption of Humic acid on Powdered Activated Carbon (PAC) Department of Civil and Environmental Engineering, MSU, East Lansing, MI, 48824, USA Abstract Removal capacity and rate of Humic Acid (HA) onto

More information

Lecture 6. Physical Properties. Solid Phase. Particle Composition

Lecture 6. Physical Properties. Solid Phase. Particle Composition Lecture 6 Physical Properties Solid Phase Particle Composition 1 Questions What are tetrahedrons and octahedrons? How do silica tetrahedra bonds affect mineral weathering? Difference between primary and

More information

Electrical double layer

Electrical double layer Electrical double layer Márta Berka és István Bányai, University of Debrecen Dept of Colloid and Environmental Chemistry http://dragon.unideb.hu/~kolloid/ 7. lecture Adsorption of strong electrolytes from

More information

Reactive transport of uranium(vi) and phosphate in a goethite-coated sand column: An experimental study

Reactive transport of uranium(vi) and phosphate in a goethite-coated sand column: An experimental study Chemosphere 68 (2007) 1218 1223 www.elsevier.com/locate/chemosphere Reactive transport of uranium(vi) and phosphate in a goethite-coated sand column: An experimental study Tao Cheng a, Mark O. Barnett

More information

Contents Preface Introduction Model Concepts

Contents Preface Introduction Model Concepts Preface xi 1 Introduction 1 1.1 Environmental Problems and Geochemical Modeling 1 1.1.1 High-Level Radioactive Waste Disposal 1 1.1.2 Mining Related Environmental Issues 4 1.1.3 Landfills 8 1.1.4 Deep

More information

Supporting Information

Supporting Information Supporting Information Enhancement of Arsenic Adsorption during Mineral Transformation from Siderite to Goethite: Mechanism and Application Huaming Guo 1, 2, *, Yan Ren 2, Qiong Liu 2, Kai Zhao 1, 2, Yuan

More information

Desorption Of (HDTMA) Hexadecyltrimethylammoniumfrom Charged Mineral Surfaces and Desorption Of Loaded Modified Zeolite Minerals

Desorption Of (HDTMA) Hexadecyltrimethylammoniumfrom Charged Mineral Surfaces and Desorption Of Loaded Modified Zeolite Minerals Desorption Of (HDTMA) Hexadecyltrimethylammoniumfrom Charged Mineral Surfaces and Desorption Of Loaded Modified Zeolite Minerals VandanaSwarnkar 1 &RadhaTomar 2 ABSTRACT: The use of surfactant-modified

More information

Adsorption of chromium from aqueous solution by activated alumina and activated charcoal

Adsorption of chromium from aqueous solution by activated alumina and activated charcoal Adsorption of chromium from aqueous solution by activated alumina and activated charcoal Suman Mor a,b*, Khaiwal Ravindra c and N. R. Bishnoi b a Department of Energy and Environmental Science, Chaudhary

More information

Priority Pollutants in Untreated and Treated Discharges from Coal Mines

Priority Pollutants in Untreated and Treated Discharges from Coal Mines Priority Pollutants in Untreated and Treated Discharges from Coal Mines Charles A. Cravotta III Research Hydrologist USGS Pennsylvania Water Science Center New Cumberland, PA Presented March, 28, 2012,

More information

Actinides (f-block) 1-1

Actinides (f-block) 1-1 Actinides (f-block) Actinide Chemistry Speciation Role of Oxidation State Complexation Specific Actinides U, Pu, Am Example: Am and Cm transport at Oak Ridge Use of laboratory data to determine chemical

More information

Global phosphorus cycle

Global phosphorus cycle Global phosphorus cycle OCN 623 Chemical Oceanography 11 April 2013 2013 Arisa Okazaki and Kathleen Ruttenberg Outline 1. Introduction on global phosphorus (P) cycle 2. Terrestrial environment 3. Atmospheric

More information

CH 221 Chapter Four Part II Concept Guide

CH 221 Chapter Four Part II Concept Guide CH 221 Chapter Four Part II Concept Guide 1. Solubility Why are some compounds soluble and others insoluble? In solid potassium permanganate, KMnO 4, the potassium ions, which have a charge of +1, are

More information

Particles in aqueous environments

Particles in aqueous environments Lecture 11 Particle-Aqueous Solute Interactions Today 1. Particle types and sizes 2. Particle charges 3. Particle-solute Interactions Next time Please continue to read Manahan Chapter 4. 1. Fresh-salt

More information

AMD 101. Chemistry of Abandoned Mine Drainage. Bruce Golden WPCAMR

AMD 101. Chemistry of Abandoned Mine Drainage. Bruce Golden WPCAMR AMD 101 Chemistry of Abandoned Mine Drainage Bruce Golden WPCAMR http://amrclearinghouse.org Western PA Coalition for Abandoned Mine Reclamation A helping hand to watershed groups grappling with the legacy

More information

Groundwater chemistry

Groundwater chemistry Read: Ch. 3, sections 1, 2, 3, 5, 7, 9; Ch. 7, sections 2, 3 PART 14 Groundwater chemistry Introduction Matter present in water can be divided into three categories: (1) Suspended solids (finest among

More information

WM 00 Conference, February 27 March 2, 2000, Tucson, AZ DIFFUSION COEFFICIENTS OF CRITICAL RADIONUCLIDES FROM RADIOACTIVE WASTE IN GEOLOGICAL MEDIUM

WM 00 Conference, February 27 March 2, 2000, Tucson, AZ DIFFUSION COEFFICIENTS OF CRITICAL RADIONUCLIDES FROM RADIOACTIVE WASTE IN GEOLOGICAL MEDIUM DIFFUSION COEFFICIENTS OF CRITICAL RADIONUCLIDES FROM RADIOACTIVE WASTE IN GEOLOGICAL MEDIUM ABSTRACT: C. Bucur, A.Popa, C. Arsene and M.Olteanu Institute for Nuclear Research, P.O. Box 78, 0300 Pitesti

More information

Study of an Unrefined Humate Solution as a Possible Remediation Method for Groundwater Contamination

Study of an Unrefined Humate Solution as a Possible Remediation Method for Groundwater Contamination STUDENT SUMMER INTERNSHIP TECHNICAL REPORT as a Possible Remediation Method for Groundwater Contamination DOE-FIU SCIENCE & TECHNOLOGY WORKFORCE DEVELOPMENT PROGRAM Date submitted: October 31, 216 Principal

More information

Scientific registration n o : 728 Symposoum n o : 6 Presentation : Poster CHOUDHARY O.P., HUNDAL H.S., KUMAR S.

Scientific registration n o : 728 Symposoum n o : 6 Presentation : Poster CHOUDHARY O.P., HUNDAL H.S., KUMAR S. Scientific registration n o : 728 Symposoum n o : 6 Presentation : Poster Competitive Adsorption of Phosphate, Molybdate, Borate and Silicate in Binary-anion mixture with soils Adsorption compétitive de

More information

CEE 371 Water and Wastewater Systems

CEE 371 Water and Wastewater Systems Updated: 22 November 2009 CEE 371 Water and Wastewater Systems Print version Lecture #23 Drinking Water Treatment: Ion Exchange, Adsorption & Arsenic Reading: Chapter 7, pp.262-266 David Reckhow CEE 371

More information

Trace elements. Geochemistry-Usually those with crustal abundance of < 100 ppm or ug/g or less

Trace elements. Geochemistry-Usually those with crustal abundance of < 100 ppm or ug/g or less The last assignment is for you to pick a paper discussing the biogeochemical cycling of a trace metal. You should provide some introduction to the metal you have chosen. You must discuss the movement or

More information

Effect of Bicarbonate on Arsenic Removal by Coagulation

Effect of Bicarbonate on Arsenic Removal by Coagulation Global Science and Technology Journal Vol. 6. No. 2. June 2018 Issue. Pp.107-122 Effect of Bicarbonate on Arsenic by Coagulation Shamontee Aziz 1, Afia Jahin 1, Zarin Tasnim 1, and Muhammad hraf Ali 1

More information

Redox transformation of arsenic. by Fe(II)-activated goethite (α-feooh)

Redox transformation of arsenic. by Fe(II)-activated goethite (α-feooh) -SUPPORTING INFORMATION- Redox transformation of arsenic by Fe(II)-activated goethite (α-feooh) Katja Amstaetter 1,2, Thomas Borch 3, Philip Larese-Casanova 1, Andreas Kappler 1 * 1 Geomicrobiology, Center

More information

Lab 8 Dynamic Soil Systems I: Soil ph and Liming

Lab 8 Dynamic Soil Systems I: Soil ph and Liming Lab 8 Dynamic Soil Systems I: Soil ph and Liming Objectives: To measure soil ph and observe conditions which change ph To distinguish between active acidity (soil solution ph) and exchangeable acidity

More information

Solubility of arsenic in Swedish contaminated soils experiments and modelling

Solubility of arsenic in Swedish contaminated soils experiments and modelling Solubility of arsenic in Swedish contaminated soils experiments and modelling Ann-Sophie Heldele Master s Thesis in Environmental Science EnvEuro European Master in Environmental Science Examensarbeten,

More information

Sensitivity of Database Selection in Modeling the Transport of Uranium

Sensitivity of Database Selection in Modeling the Transport of Uranium Golden CO; USA Reliable Mine Water Technology IMWA 2013 Sensitivity of Database Selection in Modeling the Transport of Uranium John J. Mahoney Mahoney GeochemicalConsulting,892 S. Newcombe Way, Lakewood,

More information

Chapter 3: Acid Base Equilibria. HCl + KOH KCl + H 2 O acid + base salt + water

Chapter 3: Acid Base Equilibria. HCl + KOH KCl + H 2 O acid + base salt + water Chapter 3: Acid Base Equilibria HCl + KOH KCl + H 2 O acid + base salt + water What is an acid? The Arrhenius concept proposed that acids are substances that produce hydrogen ions (H + ) in aqueous solutions.

More information

CHROMIUM ITS USES AND ITS ENVIRONMENTAL IMPACT

CHROMIUM ITS USES AND ITS ENVIRONMENTAL IMPACT CE/ESR 410/51002 Water Quality Chemistry CHROMIUM ITS USES AND ITS ENVIRONMENTAL IMPACT Background: Chromium (Cr) is a white, hard and lustrous metal, familiar in many consumer products such as the 1950

More information

SAMPLE PROBLEMS! 1. From which of the following is it easiest to remove an electron? a. Mg b. Na c. K d. Ca

SAMPLE PROBLEMS! 1. From which of the following is it easiest to remove an electron? a. Mg b. Na c. K d. Ca SAMPLE PROBLEMS! 1. From which of the following is it easiest to remove an electron? a. Mg b. Na c. K d. Ca 2. Which of the following influenced your answer to number one the most? a. effective nuclear

More information

Tikrit University. College of Engineering Civil engineering Department SOIL PROPERTES. Soil Mechanics. 3 rd Class Lecture notes Up Copyrights 2016

Tikrit University. College of Engineering Civil engineering Department SOIL PROPERTES. Soil Mechanics. 3 rd Class Lecture notes Up Copyrights 2016 Tikrit University SOIL PROPERTES College of Engineering Civil engineering Department Soil Mechanics 3 rd Class Lecture notes Up Copyrights 2016 1-Soil Composition -Solids -Water -Air 2-Soil Phases -Dry

More information

ARSENIC (As) is a toxic and metalloid element. As

ARSENIC (As) is a toxic and metalloid element. As The Effect of Phosphate and Sulfate on Arsenate Desorption From Nano-TiO 2 TING LUO* and JIAJUN YU School of Environmental Science and Engineering, 9 Xiwang Avenue, Yancheng Institute of Technology, Jiangsu

More information

Sedimentary Geology. Strat and Sed, Ch. 1 1

Sedimentary Geology. Strat and Sed, Ch. 1 1 Sedimentary Geology Strat and Sed, Ch. 1 1 Sedimentology vs. Stratigraphy Sedimentology is the study of the origin and classification of sediments and sedimentary rocks Mostly the physical and chemical

More information

Adsorption Isotherm of Phosphate Ions onto lica and Amino-modified lica from Lapindo Mud Jaslin Ikhsan 1,2, ti Sulastri 1, Erfan Priyambodo 1 1 Department of Chemistry Education, Faculty of Mathematics

More information

April 27, Ground Water in Kingwood Township

April 27, Ground Water in Kingwood Township KINGWOOD TOWNSHIP ENVIRONMENTAL COMMITTEE April 27, 2010 Ground Water in Kingwood Township Gail Ashley Debbie Kratzer Information source, unless otherwise noted: Environmental Resource Inventory for Kingwood

More information

Competitive sorption and multiple-species subsurface transport of nitro-aromatic explosives: implications for their mobility at contaminated sites

Competitive sorption and multiple-species subsurface transport of nitro-aromatic explosives: implications for their mobility at contaminated sites Groundwater Quality: Remediation and Protection (Proceedings of the GQ'98 Conference held at Tubingen, Germany, September 1998). 1AHS Publ. no. 250, f998. T7 z ' Competitive sorption and multiple-species

More information

Microorganisms. Dissolved inorganics. Native vs. Introduced; Oligotrophic vs. Eutrophic Millions to billions per ml or g Complex consortia

Microorganisms. Dissolved inorganics. Native vs. Introduced; Oligotrophic vs. Eutrophic Millions to billions per ml or g Complex consortia 1 Microorganisms Native vs. Introduced; Oligotrophic vs. Eutrophic Millions to billions per ml or g Complex consortia Species makeup: f(t, O 2, ph, nutrients, etc.) Indicators & pathogens Dissolved inorganics

More information

Geology 560, Prof. Thomas Johnson, Fall 2007 Class Notes: 3-6: Redox #2 Eh-pH diagrams, and practical applications

Geology 560, Prof. Thomas Johnson, Fall 2007 Class Notes: 3-6: Redox #2 Eh-pH diagrams, and practical applications Geology 56, Prof. Thomas Johnson, Fall 27 Class Notes: 36: Redox #2 Eh diagrams, and practical applications Reading: White, Section 3...3; Walther Ch. 4 Goals: Recognize that, because many redox reactions

More information

Lecture 6 Flotation 1. Chapter 8_Flotation of Non-Sulphide Minerals

Lecture 6 Flotation 1. Chapter 8_Flotation of Non-Sulphide Minerals Lecture 6 Flotation 1 Chapter 8_Flotation of Non-Sulphide Minerals Contents: Oxides & silicates. Adsorption & chemisorption of collectors. Activation & depression. Silica, feldspar, calcite, phosphates.

More information

CE 370. Disinfection. Location in the Treatment Plant. After the water has been filtered, it is disinfected. Disinfection follows filtration.

CE 370. Disinfection. Location in the Treatment Plant. After the water has been filtered, it is disinfected. Disinfection follows filtration. CE 70 Disinfection 1 Location in the Treatment Plant After the water has been filtered, it is disinfected. Disinfection follows filtration. 1 Overview of the Process The purpose of disinfecting drinking

More information

WHAT CAN CLAY MINERALOGY TELL US ABOUT ALTERATION ENVIRONMENTS ON MARS?

WHAT CAN CLAY MINERALOGY TELL US ABOUT ALTERATION ENVIRONMENTS ON MARS? WHAT CAN CLAY MINERALOGY TELL US ABOUT ALTERATION ENVIRONMENTS ON MARS? David Bish and David Vaniman Indiana University Los Alamos National Laboratory Products of Mineralogical Studies Mars surface mineralogy

More information

Effects of Solid-to-Solution Ratio on Uranium(VI) Adsorption and Its Implications

Effects of Solid-to-Solution Ratio on Uranium(VI) Adsorption and Its Implications Environ. Sci. Technol. 2006, 40, 3243-3247 Effects of Solid-to-Solution Ratio on Uranium(VI) Adsorption and Its Implications TAO CHENG, MARK O. BARNETT,*, ERIC E. RODEN, AND JINLING ZHUANG Department of

More information

Antimony (V) removal from water by zirconium-iron binary oxide: performance and mechanism

Antimony (V) removal from water by zirconium-iron binary oxide: performance and mechanism Antimony (V) removal from water by zirconium-iron binary oxide: performance and mechanism X.M. Dou, X.H. Li, Y.S. Zhang College of Environment Science and Technology, Beijing Forestry University, Beijing

More information