Effect of pre-treatments on the biosorption of Chromium (VI) ions by the dead biomass of Rhizopus arrhizus

• Published in: Journal of chemical technology and biotechnology (1986) Vol. 87; no. 2; pp. 294 - 304
• Main Authors: Shroff, Kshama A., Vaidya, Varsha K.
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.02.2012; Wiley
• Subjects: Adsorption; Applied sciences; Biological and medical sciences; biosorption; Biotechnology; Chemical engineering; chemical modification; Cr(VI); Exact sciences and technology; FTIR spectroscopy; Fundamental and applied biological sciences. Psychology; Methods. Procedures. Technologies; Others; pre-treatment; Rhizopus arrhizus; Various methods and equipments; Scanning electron microscopy; pre-treatment; Electrostatic interaction; Biomass; Uptake; FTIR spectroscopy; Organic solvent; Rhizopus arrhizus; Chemical modification; Biosorption; Cr(VI); Adsorption; Batchwise; Chemical treatment; Chelating agent; Aqueous solution; Fourier-transformed infrared spectrometry; Surface area
• ISSN: 0268-2575; 1097-4660
• DOI: 10.1002/jctb.2715

BACKGROUND: This work fulfils the need to develop an eco‐friendly biosorbent, elucidating the mechanism of biosorption. Removal of Cr(VI) by Rhizopus arrhizus was investigated in batch mode. Enhancement in the performance of the biosorbent was attempted by pre‐treating the biomass with inorganic and organic acids, chelating agent, cross‐linker and an organic solvent followed by autoclaving. The surface characterization of the biomass was carried out by potentiometric titration, surface area analysis, infrared spectroscopy, chemical modification of the biomass and scanning electron microscopy. RESULTS: All the physico‐chemical treatments of the biosorbent improved Cr(VI) uptake compared with the native biomass (21.72 mg g−1). The highest biosorption capacity (31.52 mg g−1) was achieved after pre‐treating the biomass with 0.5 mol L−1 HNO3 followed by autoclaving. Surface characterization of the biomass using pHzpc, potentiometry and Fourier transform infrared (FTIR) analysis revealed the role of amino and carboxyl groups in Cr(VI) removal by electrostatic attraction. Chemical modification of amino and carboxyl groups significantly decreased Cr(VI) uptake capacity confirming their role in biosorption. SEM analysis showed adsorption of Cr(VI) on the biosorbent surface. CONCLUSION: Rhizopus arrhizus biomass proved to be an effective and low cost alternative biosorbent for removal of Cr(VI) from aqueous solutions. Copyright © 2011 Society of Chemical Industry