Analysis of Acid Alizarin Violet N Dye Removal Using Sugarcane Bagasse as Adsorbent

Transcription

1 Water Air Soil Pollut (2012) 223: DOI /s z Analysis of Acid Alizarin Violet N Dye Removal Using Sugarcane Bagasse as Adsorbent Eduardo Kovalski Mitter & Graziely Cristina dos Santos & Érica Janaína Rodrigues de Almeida & Luana Galvão Morão & Heide Dayane Prates Rodrigues & Carlos Renato Corso Received: 18 May 2011 /Accepted: 19 July 2011 /Published online: 11 August 2011 # Springer Science+Business Media B.V Abstract With the development of the textile industry, there has been a demand for dye removal from contaminated effluents. In recent years, attention has been directed toward various natural solid materials that are capable of removing pollutants from contaminated water at low cost. One such material is sugarcane bagasse. The aim of the present study was to evaluate adsorption of the dye Acid Violet Alizarin N with different concentrations of sugarcane bagasse and granulometry in agitated systems at different ph. The most promising data (achieved with ph 2.5) was analyzed with both Freundlich and Langmuir isotherms equations. The model that better fits dye E. K. Mitter : G. C. dos Santos : É. J. R. de Almeida : L. G. Morão : H. D. P. Rodrigues : C. R. Corso (*) Department of Biochemistry and Microbiology, Sao Paulo State University (UNESP), 24-A Avenue, 1515, Postal Code: Rio Claro, Sao Paulo, Brazil crcorso@rc.unesp.br E. K. Mitter edumitter@gmail.com G. C. dos Santos grazybio@yahoo.com.br É. J. R. de Almeida jani_430@hotmail.com L. G. Morão luanagm@rc.unesp.br H. D. P. Rodrigues heidedayane@yahoo.com.br adsorption interaction into sugarcane bagasse is Freundlich equation, and thus the multilayer model. Moreover, a smaller bagasse granulometry led to greater dye adsorption. The best treatment was achieved with a granulometry value lower than 0.21 mm at ph 2.50, in which the total removal was estimated at a concentration of mg ml 1. Hence, sugarcane bagasse proves to be very attractive for dye removal from textile effluents. Keywords Sugarcane bagasse. Textile. Dyes. Acid alizarin violet N. Adsorption 1 Introduction Dyes are organic chemical compounds that selectively absorb visible light. These compounds appear colored due to the presence of chromophore groups, such as nitro, nitrous, azo, and carbonyl. The color of these compounds is enhanced and/or modified by auxochrome groups, such as ethyl, nitro, amino, sulfonic, hydroxyl, methoxy, ethoxy, chlorine, and bromine (Immich et al. 2009). Reactive dyes are used on an increasing scale in textile industries due to their reactivity with fibers and their color stability (Vitor and Corso 2008). Textile industries consume large quantities of water and chemicals, especially in dyeing and finishing processes. On average, 60% to 90% of total water consumption is spent in washing processes (Daneshvar et al. 2004).

2 766 Water Air Soil Pollut (2012) 223: From the toxicological standpoint, textile dyes are absorbed by a variety of organisms due to their high degree of solubility in water. Reactive dyes not only react with natural fibers, but also with proteins and cellulose in plants. According to Cardoso et al. (2011), besides the risk of dermatitis, the major risk of contamination by these compounds is through oral ingestion, as dyes catalyzed by specific enzymes in the body can result in carcinogenic and mutagenic substances. In aquatic systems, dyes cause changes in the photosynthetic activities of plants by preventing the penetration of solar radiation. Due to the growing concern with the environment, treatment systems for contaminated wastewaters have been studied. Such studies are currently based on the recovery, recycling, and reuse of treated effluents, which both benefits the environment and reduces manufacturing costs (Souza et al. 2008). Adsorption is considered superior to other techniques for the removal of these compounds and is therefore frequently employed in the textile industry. Adsorption is a mass solid fluid transfer process that exploits the ability of certain solids to concentrate certain substances in liquid or gas form on their surface, allowing the separation of these substances from other components in a solution (Leal et al. 2010). Since these components are gathered on the outer surface of the solid, a larger contact surface leads to better adsorption capacity. Another advantage of this process is the ability to recover a dye in concentrated form, as well as the reuse of the adsorbent (Immich et al. 2009). Various modeling approaches have been used to describe dye adsorption in a solid surface. Historically, adsorption has been described using empirical models such as Langmuir and Freundlich adsorption isotherm equations (Mittal et al. 2007). Langmuir's adsorption isotherm has successful applications in many sorption processes of monolayer adsorption. This model of adsorption depends on the assumption that intermolecular forces decrease rapidly with distance and consequently predicts the existence of monolayer coverage of the adsorbate at the outer surface of the adsorbent (Wong et al. 2004). Thus, Freundlich equation predicts that dye concentrations on the adsorbent will increase as long as there is an increase in the dye concentration in the liquid. This multilayer adsorption model states that adsorption decreases logarithmically as the surface will become covered by the solute (Tseng and Wu 2009). In recent years, attention has been directed toward various natural solid materials capable of removing pollutants from contaminated water at low cost (Cardoso et al. 2011). A number of residues are obtained in the sugarcane milling process, including bagasse (Oliveira et al. 2006). Over the years, a large amount of bagasse has accumulated due to the expansion of sugarcane crops in Brazil. Bagasse can be incinerated to generate heat in boilers and supply electricity to the plant. However, the industry discharges kg of bagasse per ton of sugarcane (Masson et al. 2007). Activated carbon is currently the most widely used adsorbent because it has excellent adsorption efficiency, but is extremely expensive for textile industries (Garg et al. 2004). Hence, sugarcane bagasse is a suitable and economically attractive alternative for textile effluents dye removal. Therefore, the aim of the present study was to evaluate Acid Alizarin Violet N dye adsorption at different sugarcane bagasse concentrations and granulometries under agitated systems at different ph values. 2 Materials and Methods 2.1 Screening and Bagasse Preparation Bagasse was collected and shredded. Through screening, the in natura sample was separated into three different sizes: less than 0.21 mm, between 0.21 and 0.35 mm, and between 0.35 and 0.45 mm. 2.2 Preparation of Dye Stock Solution The dye stock solution was obtained from 100 mg of Acid Alizarin Violet N manufactured by Sigma-Aldrich, which was dissolved in 100-mL distilled water at ph 7.00 for a final concentration of 1,000 μg/ml. 2.3 Scanning of Dye and Determination of Standard Equation Six different dilutions of the stock solution were placed in numbered test tubes (20, 40, 60, 80, and 100 μg/ml). The dilutions were performed at all ph values analyzed (2.50, 4.50, 6.50, and 8.50).

3 Water Air Soil Pollut (2012) 223: Each diluted solution was placed in a 0.5-cm quartz cuvette for UV-vis spectrophotometer scanning. In preliminary tests, Acid Alizarin Violet N (Sigma- Aldrich) was characterized as having unstable ph. Therefore, the absorbance reading to calculate the dye concentration in a given solution was performed using the isobestic point, which is the point at which the absorbance values of a given concentration overlap at different ph values (Fig. 1). From the absorbance values at the isobestic point and dye concentration in the solution (grams per milliliter), the standard equation was determined from graphs using the Origin Professional 5.0 program for all ph values studied. The values of A, B, and R in the equation were recorded in order to calculate the amount of remaining dye in subsequent experiments with bagasse (Fig. 2). 2.4 Agitation Agitation was performed in a mechanical agitator at 160 rpm for 2 h, with room temperature maintained at 25 C±4 and in the absence of light. 2.5 Trials with Different Concentrations of Bagasse The experiments were performed in duplicate in test tubes with different sugarcane bagasse concentrations (20, 40, 60, 80, and 100 mg). In each tube containing bagasse, 1 ml of dye stock solution (1,000 μg/ml) and 9 ml of distilled water were added at ph 2.50, 4.50, and 8.50, obtaining a final dye concentration of 100 μg/ml. Also, a control experiment was prepared containing dye solution only.after agitation, the samples were filtered through a Fig. 2 Chemical structure of Acid Alizarin Violet N semi-synthetic filter, which retained the bagasse and left only the remaining solution. The solutions were then analyzed with regard to UV-vis spectra using the isobestic point, and the absorbance data were transferred to the Origin 5.0 Professional program. 2.6 Calculation of Total Dye Removal Through the standard equation obtained for each ph value, the remaining concentration of dye was calculated in the different bagasse solutions. The mean values of the two replicates were plotted on a new graph, from which the equation of the line was also obtained. Through this equation, the concentration of dye remaining in each bagasse solution was calculated to estimate the concentration of bagasse required for complete dye adsorption (total dye removal). For such, the x value of bagasse concentration (milligrams per milliliter of bagasse) was determined for the obtainment of y=0 (zero dye concentration in micrograms per milliliter). 2.7 Freundlich and Langmuir Isotherms Adsorption Studies The adsorption isotherms were evaluated from the equations of Freundlich and Langmuir and allowed to evaluate the adsorption kinetic adsorption interaction. These calculations were performed using the absorbance values of initial and remaining dye concentrations along with the sugarcane bagasse mass used. The equations adapted by Fukuchi and Arai (1989) are described below: 1) Freundlich equation: Fig. 1 Acid Alizarin Violet N scanning in 60 μg/ml; isobestic point determined at 526 nm. 1 ph 2.50, 2 ph 7.00, 3 ph logðx=mþ ¼ log k þ n:log Cr

4 768 Water Air Soil Pollut (2012) 223: n liquid dye solution per adsorbent weight (liters per gram). 2) Langmuir equation: Cr: ðm=xþ ¼ 1= ðk1:k2þþð1=k2þ:cr Where, k1 k2 dye capillarity index expressed in milliliters per adsorbed dye (micrograms) at saturation (1 per microgram). solute that would saturate a single layer adsorbent mass unit (milligrams per milligram). Fig. 3 Adsorptive interaction of Acid Alizarin Violet N dye solution with bagasse granulometry size less than 0.21 mm under agitation (160 rpm); initial dye concentration: 100 μg/ml; interaction time: 120 min at ph 2.50; temperature: 25 C; estimated bagasse concentration for total dye removal: mg ml 1 ; standard equation: Y (concentration of remaining dye)= ; X (concentration of bagasse), R= Where, x/m adsorbed dye concentration per adsorbent mass unit (milligrams per milligram). Cr remaining dye concentration in solution (milligrams per milliliter). K x/m, where Cr is equal to 1. The best ph adsorption interaction data collected was analyzed in both Freundlich and Langmuir isotherms equations. Then, the best adsorption model that fits the data was verified. 3 Results and Discussion Among all ph values tested, ph 2.50 proved to be the most efficient, requiring the least amount of bagasse for total dye removal. Total removal was achieved at a bagasse concentration of mg ml 1 with granulometry between 0.35 and 0.45 mm, mg ml 1 with granulometry between 0.21 and 0.35 mm, and Fig. 4 Adsorptive interaction of Acid Alizarin Violet N dye solution with bagasse granulometry size from 0.21 to 0.35 mm under agitation (160 rpm); initial dye concentration: 100 μg/ml; interaction time: 120 min at ph 4.50; temperature: 25 C; estimated bagasse concentration for total dye removal: mg ml 1 ; standard equation: Y (concentration of remaining dye)= ; X (concentration of bagasse), R= Fig. 5 Adsorptive interaction of Acid Alizarin Violet N dye solutionwithbagassegranulometrysizefrom0.21to0.35mm under agitation (160 rpm); initial dye concentration: 100 μg/ml; interaction time: 120 min at ph 6.50; temperature: 25 C; estimated bagasse concentration for total dye removal: mg ml 1 ; standard equation: Y (concentration of remaining dye)= ; X (concentration of bagasse), R=

5 Water Air Soil Pollut (2012) 223: Table 2 Parameters obtained for the adsorptive interaction of Acid Alizarin Violet N dye solution with sugarcane bagasse according to Freundlich's isotherm Parameters Granulometry (mm) Less than to to 0.45 Slope Intercept (log K) k Correlation coefficient Fig. 6 Adsorptive interaction of Acid Alizarin Violet N dye solution with bagasse granulometry size from 0.21 to 0.35 mm under agitation (160 rpm); initial dye concentration: 100 μg/ml; interaction time: 120 min at ph 8.50; temperature: 25 C; estimated bagasse concentration for total dye removal: mg ml 1 ; standard equation: Y (concentration of remaining dye)= ; X (concentration of bagasse), R= 0, mg ml 1 with granulometry less than 0.21 mm. Thus, under the conditions tested, small bagasse particle sizes achieved more efficient dye removal (Fig. 3). At ph 4.50, the same tendency of dye removal occurred with regard to bagasse granulometry, although the figures for total removal were higher than those found for ph With bagasse granulometry between 0.35 and 0.45 mm, 70.0 mg ml 1 of bagasse would be necessary to obtain dye total removal. For granulometry Table 1 Results of total removal according to granulometry and ph ph Granulometry (mm) Bagasse concentration for total removal (mg/ml) 2.50 Less than to to Less than to to Less than to to Less than to to between 0.21 and 0.35 mm, this figure would be mg ml 1, and for smaller than 0.21 mm, 38.5 mg ml 1 would be required for total dye removal, which is more than twice the concentration as that required in the experiments with ph 2.50 (Fig. 4). At ph 6.50, the same tendency occurred as in the previous experiments. Under this condition, lower concentrations of bagasse were needed for the total removal of Acid Alizarin Violet N with granulometrylessthan 0.21 mm. Thus, mg of bagasse per milliliter was needed for total dye removal. Total removal required a concentration of mg ml 1 with granulometry from 0.35 to 0.45 mm and mg ml 1 with granulometry from 0.21 to 0.35 mm. According to Leal et al. (2010), an increase in ph leads to a decrease in dye adsorbed, with an average adsorbent mass of mg/g, whereas a decrease in granulometry and porosity of the material leads to an increase in adsorption capacity (Fig. 5). For the experiments using distilled water at ph 8.50, the concentration of bagasse needed for total removal with granulometry from 0.35 to 0.45 mm was mg ml 1.Thisfigurewas78.52mgmL 1 with Table 3 Parameters obtained for the adsorptive interaction of Acid Alizarin Violet N dye solution with sugarcane bagasse according to Langmuir's isotherm Parameters Granulometry (mm) Less than to to 0.45 Slope Intercept k k Correlation coefficient

6 770 Water Air Soil Pollut (2012) 223: granulometryfrom0.21to0.35mmand51.91mgml 1 with particle sizes smaller than 0.21 mm. Thus, these results do not exhibit the same tendency as in the previous experiments carried out at lower ph values. Moreover, the estimated values for total removal were the highest at ph 8.50 than all other ph values studied (Fig. 6). As the results for ph 2.50 indicates the most promising results for total dye removal. The correlation coefficients obtained by fitting the resulting dye concentrations in both isotherms equations indicate that Freundlich's equation is more suitable than Langmuir's (Tables 1, 2, and 3). Corso and Almeida (2009) exposed autoclaved and non-autoclaved fungal biomass to textile dye solutions and toxicity levels decreased concomitantly with dye removal as the entire dye molecule is removed from the effluent. Therefore, as Acid Alizarin Violet N dye solution is being adsorbed by sugarcane bagasse, toxicity levels will decrease as well. 4 Conclusions Based on the results of the present study, an increase in ph in the solution leads to a decrease in adsorption capacity of Acid Alizarin Violet N dye on sugarcane bagasse. The lowest concentration of bagasse for total dye removal was obtained at ph 2.50, which therefore represents the most promising results. With regard to particle size, a larger granulometry leads to lesser adsorption, as the best treatment was obtained with granulometry smaller than 0.21 mm. The model that better fits dye adsorption interaction into sugarcane bagasse is Freundlich equation, and thus the multilayer model. Hence, sugarcane bagasse proves to be highly attractive in dye removal from textile effluents allowing textile water reuse. The remaining dye adsorbed in sugarcane bagasse can either be desorbed or incinerated. References Cardoso, N. F., Lima, E. C., Pinto, I. S., Amavisca, C. V., Royer, B., Pinto, R. B., et al. (2011). Application of cupuassu shell as biosorbent for the removal of textile dyes from aqueous solution. Journal of Environmental Management, 92(4), Corso, C. R., & Almeida, A. C. M. (2009). Bioremediation of dyes in textile effluents by Aspergillus oryzae. Microbial Ecology, 57(2), Daneshvar, N., Sorkhabi, H. A., & Kasiri, M. B. (2004). Decolorization of dye solution containing acid red 14 by electrocoagulation with a comparative investigation of different electrode connections. Journal of Hazardous Materials, 112(1 2), Fukuchi, K., & Arai, Y. (1989). Measurement and prediction of adsorption equilibria of organic solutes from dilute aqueous solutions on activated carbon. Colloids and Surfaces. doi: / (89) Garg, V. K., Amita, M., Kumar, R., & Gupta, R. (2004). Basic dyes (methylene blue) removal from simulated wastewater by adsorption using Indian Rosewood sawdust: A timber industry waste. Dyes and Pigments, 63(3), Immich, A. P. S., De Souza, A. A. U., & De Souza, S. M. D. G. U. (2009). Adsorption of remazol blue RR from textile effluents using Azadirachta indica leaf powder as an alternative adsorbent. Adsorption Science and Technology, 27(5), Leal, C. C. A., Da Rocha, O. R. S., Duarte, M. M. M. B., Dantas, R. F., Da Motta, M., De Lima, N. M., et al. (2010). Evaluation of the adsorption process of remazol black B dye in liquid effluents by green coconut mesocarp. Afinidad, 66(546), Masson, J., Cardoso, M. G., Vilela, F. J., Pimentel, F. A., De Morais, A. R., & Dos Anjos, J. P. (2007). Physicochemical and chromatographic parameters in sugar cane brandies from burnt and non-burnt cane. Ciência Agrotécnica, 31 (6), Mittal, A., Kurup, L., & Mittal, J. (2007). Freundlich and Langmuir adsorption isotherms and kinetics for the removal of tartrazine from aqueous solutions using hen feathers. Journal of Hazardous Materials, 146(1 2), Oliveira,M.M.,Pimenta,M.E.S.G.,Camargo,A.C.S., Fiori, J. E., & Pimenta, C. J. (2006). Silage of tilapia (Oreochromis niloticus) filetage residues with formic acid Bromatological, phisico-chemical and microbiological analyses. Ciência Agrotécnica, 30(6), Souza, S. M. A. G. U., Peruzzo, L. C., & Souza, A. A. U. (2008). Numerical study of the adsorption of dyes from textile effluents. Applied Mathematical Modelling, 32(9), Tseng, R. L., & Wu, F. C. (2009). Analyzing a liquid solid phase countercurrent two- and three-stage adsorption process with the Freundlich equation. Journal of Hazardous Materials, 162(1), Vitor, V., & Corso, C. R. (2008). Decolorization of textile dye by Candida albicans isolated from industrial effluents. Journal of Industrial Microbiology and Biotechnology, 35 (11), Wong, Y. C., Szeto, Y. S., Cheung, W. H., & Mckay, G. (2004). Adsorption of acid dyes on chitosan-equilibrium isotherm analyses. Process Biochemistry, 39(6),