Laterite and modified laterite as efficient arsenic adsorbents Yoann Glocheux Dr. Gavin Walker Pr. Stephen Allen ATWARM meeting 01/05/12, Cranfield University, Cranfield
Plan Introduction Material presentation Arsenic adsorption results Work future outreach 2
1. Introduction Arsenic groundwater contamination Arsenic is a deadly component at high concentration Groundwater arsenic contamination is a dilute pollution As accumulates in organisms because of its similarity with P Typical arsenic groundwater levels are 100 1000 ppb The WHO recommendation level is 10 ppb! Fe, Al and Ti oxides/hydroxides have good affinity toward As Figure 1 : Arsenicosis [1] Figure 2 : POE treatment [2] Figure 3 : POU treatment [3] 3
2. Material presentation Laterite A natural ore rich in Al, Fe and Ti oxides Present in India, Bangladesh and Northern Ireland! Laterite is treated by H 2 SO 4 to produce FAS for WWT plants 1 cm 1 cm Figure 4 : Laterite Figure 5 : Acidified Laterite Table 1. XRF analysis of Laterite and Acidified Laterite samples 4
2. Material presentation Acid treatment H 2 SO 4 leaching solubilize preferably Al HCl was used for Fe leaching (6 M HCl at 60 C) Table 2. ICP-OES analysis of HCl leaching from Laterite sample Material synthesis Metals were gradually precipitated using NH 4 OH solution Precipitate was aged, recovered, dried and washed Use of surfactant was investigated to increase surface area Use of iron chloride as source of iron was also studied 5
2. Material presentation Materials parameters Surface area, porosity and pore size were measured PZC is an important parameter in As(V) adsorption Bayoxide from Lanxess was used to compare results Hydrolysed Acid Leaching Laterite (HALL) Table 3. Characteristics of materials tested BET Particle size PZC Fe source m 2.g 1 ml.g 1 nm µm at 0.01 M NaCl Bayoxide Akaganeite 124.15 0.766 12.34 500 710 8.3 Laterite Goethite and 24.79 0.084 6.74 < 75 7.6 Acidified Laterite (H 2 SO 4 ) HALL magnetite Goethite and magnetite Laterite HCl leaching 1 cm Figure 6 : HALL 85.70 0.183 4.27 < 75 4.1 5.1 75.63 0.059 1.56 500 710 7.7 6
3. As adsorption results Isotherms Concentration studies with Langmuir or Freundlich models As(III) As(V) Figure 7 : Arsenic concentration studies of adsorbents for both As(IIII) and As(V) 7
3. As adsorption results Kinetics Experiments results with pseudo 1 st or pseudo 2 nd order model As(III) As(V) Figure 8 : Arsenic kinetics studies of adsorbents for both As(IIII) and As(V) 8
3. Arsenic adsorption results ph study PZC: Bayoxide: 8.3 HALL: 7.7 As(III) is uncharged between ph 5-9 As(V) is negatively charged between ph 5-9 Figure 9 : Arsenic ph study for both As(IIII) and As(V) 9
3. Arsenic adsorption results Regeneration As desorption at high ph, study limited to Acidified Laterite Figure 10 : Regeneration studies, desorption screening and adsorption cycles 10
3. Arsenic adsorption results Comparison Very good As adsorption capacity of HALL material Table 4. Arsenic adsorption capacity comparison As removal capacity at 100 ppb in mg.g 1 As(III) As(V) Model This study Laterite 0.12 0.16 Freundlich This study Acidified laterite 0.29 0.84 Freundlich This study Bayoxide 5.63 3.70 Langmuir [4] Modified laterite 3.13 14.54 Langmuir [5] Ordered alumina 5.00 19.80 Column study This study HALL 4.50 20.20 Langmuir 11
3. Arsenic adsorption results P removal with same materials Results from Martin Mendez, Master thesis at QUB (2012) Table 5. Phosphate adsorption capacity comparison Adsorbent q m (mg g 1 ) Prange (ppm) Particle size Martin Mendez 2012 Acidified Laterite 2.75 1 50 < 75 µm Martin Mendez 2012 HALL 41.5 1 50 500 710 µm [6] Laterite 1.01 5 30 590 750 µm [7] Acidified fly ash 90.09 50 2000 < 50 µm [8] Active red mud 95.86 1 2500 10 mesh (2 mm) 12
4. Work future outreach Work plan Secondment on Hard Templating Extrusion of powder into granules Columns study Chemical surface analysis As(III) + As(V) adsorption Wider impacts Figure 11 : Hard templating replicate (CoO 3 ) [9] Design of a pilot plant (POU scale) Test on field in collaboration with Dr Sengupta (SPACE, QUB) Project onto P removal (low concentration) 13
References [1] A. H. Smith, E. O. Lingas, M. Rahman, and others, Contamination of drinking water by arsenic in Bangladesh: a public health emergency, Bulletin of the World Health Organization, vol. 78, no. 9, pp. 1093 1103, 2000. [2] J. Valigore, A. S.. Chen, L. Wang, N. R. M. R. L. (US). O. of Research, Development, and B. M. Institute, Arsenic Removal from Drinking Water by Adsorptive Media: US EPA Demonstration Project at Rimrock, AZ: Final Performance Evaluation Report, National Risk Management Research Laboratory, Office of Research and Development, US Environmental Protection Agency, 2008. [3] S. Kommineni, H. Durbin, and R. Narasimhan, Point of use, Point of entry Treatment for Arsenic Removal: Operational Issues and Costs, 2003. [4] A. Maiti, J. K. Basu, and S. De, Experimental and kinetic modeling of As(V) and As(III) adsorption on treated laterite using synthetic and contaminated groundwater: Effects of phosphate, silicate and carbonate ions, Chemical Engineering Journal, no. 0, 2010. [5] W. Li, C. Y. Cao, L. Y. Wu, M. F. Ge, and W. G. Song, Superb fluoride and arsenic removal performance of highly ordered mesoporous aluminas, Journal of Hazardous Materials, vol. 198, no. 0, pp. 143 150, Dec. 2011. [6] L. Zhang, S. Hong, J. He, F. Gan, and Y. Ho, Adsorption characteristic studies of phosphorus onto laterite, Desalination and Water Treatment, vol. 25, no. 1 3, pp. 98 105, 2011. [7] S. G. Lu, S. Q. Bai, L. Zhu, and H. D. Shan, Removal mechanism of phosphate from aqueous solution by fly ash, Journal of Hazardous Materials, vol. 161, no. 1, pp. 95 101, Jan. 2009. [8] C. LIU, Y. LI, Z. LUAN, Z. CHEN, Z. ZHANG, and Z. JIA, Adsorption removal of phosphate from aqueous solution by active red mud, Journal of Environmental Sciences, vol. 19, no. 10, pp. 1166 1170, 2007. [9] A. Rumplecker, Host guest chemistry of mesoscopically ordered porous materials, Ruhr Universität Bochum, Universitätsbibliothek, 2007. 14
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