Biosorption of copper ions using rhizoplane bacterial isolates isolated from Eicchornia crassipes ((Mart.) solms) with kinetic studies

Biosorption of Cu ions from the aqueous solution was studied with Pseudomonas putida and Bacillus cereus, isolated from rhizoplane region of water hyacinth (Eichhornia crassipes) using pure culture technique. The effect of contact time (0, 4, 8, 12, 16, 20, and 24 h), pH (3, 5, 7, and 9), temperature (25, 37, and 45°C), and initial concentrations of Cu ions (50–1500 mg l−1) on biosorption was investigated in batch systems. Better amount of biosorption of Cu ions (500 mg l−1) from the tested biosorbents was found to be 84.8% by P. putida and 83.8% by B. cereus at pH 7. The biosorbed Cu ions by P. putida and B. cereus were 420 and 415 mg l−1, respectively, at 500 mg l−1 of Cu ion concentration. The results of pseudo-second-order kinetics were considered as the most appropriate model which predicted the biosorption capacity of both the bacterial isolates with comparison to the experimental results. Langmuir and Freundlich isotherms were used to evaluate the experimental data and their constants were derived. From the data analysis, Freundlich isotherm was fitted well followed by Langmuir isotherm model.