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Chromium binding capacity of Lyngbya putealis exopolysaccharides

Paper ID Volume ID Publish Year Pages File Format Full-Text
4740 241 2008 8 PDF Available
Title
Chromium binding capacity of Lyngbya putealis exopolysaccharides
Abstract

This paper presents the chromium adsorptive potential of polysaccharide produced by a novel cyanobacterium Lyngbya putealis HH-15. Batch mode experiments were performed to determine the adsorption equilibrium and the equilibrium data was applied to different two-parameter models (Langmuir, Freundlich, Temkin, Dubinin–Radushkevich, Flory–Huggins, and Brunauer, Emmer & Teller (BET) model). The highest coefficient of determination (0.9925) for Langmuir and BET models indicates best fitness of these models in explaining the sorption as a multilayer process. Effect of different variables like initial metal ion concentration (10–100 mg/L), pH (2–6) and temperature (25–45 °C) on chromium adsorption of exopolysaccharides (EPS) were also examined, using Box–Behnken design model. Very high value of regression coefficient between the variables and the response (R2 = 0.9982) indicates excellent evaluation of experimental data by second-order polynomial regression model. The response surface method indicated that 30–40 mg/L initial chromium concentration, pH 2 and 45 °C temperature were optimal for biosorption of chromium by the cyanobacterial exopolysaccharides. Adsorption capacity of EPS increased from 45 to 157 mg/g of EPS as initial Cr(VI) concentration increased from 10 to 30 mg/L. Surface adsorption of the metal at surface of EPS was confirmed through scanning electron microscopy.

Keywords
Exopolysaccharides; Chromium; Lyngbya putealis; Response surface methodology; Adsorption isotherms
First Page Preview
Chromium binding capacity of Lyngbya putealis exopolysaccharides
Publisher
Database: Elsevier - ScienceDirect
Journal: Biochemical Engineering Journal - Volume 38, Issue 1, 15 January 2008, Pages 47–54
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering