Cr(VI) sorption by free and immobilised chromate-reducing bacterial cells in PVA–alginate matrix: equilibrium isotherms and kinetic studies

• Published in: Environmental science and pollution research international 2013-08, Vol.20 (8), p.5198-5211
• Main Authors: Rawat, Monica, Rawat, A. P., Giri, Krishna, Rai, J. P. N.
• Format: Article
• Language: English
• Subjects: Adsorption; Air pollution; Alginates - chemistry; Alginic acid; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Bacteria; Bioaccumulation; Biomass; Bioremediation; Biosorption; Cell walls; Chromate; Chromium; Chromium - chemistry; Chromium - metabolism; Comparative analysis; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Equilibrium; Fourier analysis; Fourier transforms; Glucuronic Acid - chemistry; Heavy metals; Hexuronic Acids - chemistry; Industrial Waste; Infrared spectroscopy; Isotherms; Kinetics; Laboratories; Microorganisms; Morphology; Paenibacillus; Paenibacillus - chemistry; Paenibacillus - isolation & purification; Paenibacillus - metabolism; Polyvinyl alcohol; Polyvinyl Alcohol - chemistry; Research Article; rRNA 16S; Soil Microbiology; Soil microorganisms; Studies; Tanning; Toxicity; Waste Water Technology; Water Management; Water Pollutants, Chemical - chemistry; Water Pollutants, Chemical - metabolism; Water Pollution Control
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-013-1493-4

Chromate-resistant bacterial strain isolated from the soil of tannery was studied for Cr(VI) bioaccumulation in free and immobilised cells to evaluate its applicability in chromium removal from aqueous solution. Based on the comparative analysis of the 16S rRNA gene, and phenotypic and biochemical characterization, this strain was identified as Paenibacillus xylanilyticus MR12. Mechanism of Cr adsorption was also ascertained by chemical modifications of the bacterial biomass followed by Fourier transform infrared spectroscopy analysis of the cell wall constituents. The equilibrium biosorption analysed using isotherms (Langmuir, Freundlich and Dubinin–Redushkevich) and kinetics models (pseudo-first-order, second-order and Weber–Morris) revealed that the Langmuir model best correlated to experimental data, and Weber–Morris equation well described Cr(VI) biosorption kinetics. Polyvinyl alcohol alginate immobilised cells had the highest Cr(VI) removal efficiency than that of free cells and could also be reused four times for Cr(VI) removal. Complete reduction of chromate in simulated effluent containing Cu 2+ , Mg 2+ , Mn 2+ and Zn 2+ by immobilised cells, demonstrated potential applications of a novel immobilised bacterial strain MR12, as a vital bioresource in Cr(VI) bioremediation technology.