Biosorption of hexavalent chromium by raw and acid-treated green alga Oedogonium hatei from aqueous solutions

• Published in: Journal of hazardous materials Vol. 163; no. 1; pp. 396 - 402
• Main Authors: Gupta, V.K., Rastogi, A.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 15-04-2009; Elsevier
• Subjects: Acids - pharmacology; Adsorption; Applied sciences; Biological and medical sciences; Biosorption; Biotechnology; Chemical engineering; Chlorophyta - drug effects; Chlorophyta - metabolism; Chromium - metabolism; Diffusion; Exact sciences and technology; FTIR; Fundamental and applied biological sciences. Psychology; Hexavalent chromium; Hydrogen-Ion Concentration; Kinetic models; Methods. Procedures. Technologies; Oedogonium; Oedogonium hatei; Others; Pollution; Solutions; Temperature; Thermodynamic parameters; Thermodynamics; Time Factors; Various methods and equipments; Hexavalent chromium; Thermodynamic parameters; Biosorption; Oedogonium hatei; Kinetic models; FTIR; Second order; Algae; Adsorption isotherm; Metal ion; Biomass; Modeling; Kinetic model; Adsorption; Batchwise; First order; Thermodynamic parameter; pH; Kinetics; Chemical properties; Aqueous solution; Diffusion; Boundary layer
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2008.06.104

The hexavalent chromium, Cr(VI), biosorption by raw and acid-treated
Oedogonium hatei were studied from aqueous solutions. Batch experiments were conducted to determine the biosorption properties of the biomass. The optimum conditions of biosorption were found to be: a biomass dose of 0.8
g/L, contact time of 110
min, pH and temperature 2.0 and 318
K respectively. Both Langmuir and Freundlich isotherm equations could fit the equilibrium data. Under the optimal conditions, the biosorption capacities of the raw and acid-treated algae were 31 and 35.2
mg Cr(VI) per g of dry adsorbent, respectively. Thermodynamic parameters showed that the adsorption of Cr(VI) onto algal biomass was feasible, spontaneous and endothermic under studied conditions. The pseudo-first-order kinetic model adequately describe the kinetic data in comparison to second-order model and the process involving rate-controlling step is much complex involving both boundary layer and intra-particle diffusion processes. The physical and chemical properties of the biosorbent were determined and the nature of biomass–metal ions interactions were evaluated by FTIR analysis, which showed the participation of
COOH,
OH and
NH
2 groups in the biosorption process. Biosorbents could be regenerated using 0.1
M NaOH solution, with up to 75% recovery. Thus, the biomass used in this work proved to be effective materials for the treatment of chromium bearing aqueous solutions.