Removal of congo red fromaqueous solutions using plant biomass: equilibrium&kinetic studies

Author(s): P.Kalpana, V.Omkar, P.King

Biosorption is potentially an attractive technology for the treatment of waste water for retaining dyes from dilute solutions. Studies carried through environmental biotechnology have shown that many biosorbents present in the nature have great capacity for removal of dyes. Biosorption of Congo red on bauhinia purpurea leaves had been studied and compared by using batch techniques. The biosorption experiments were performed under various conditions such as different initial concentrations, pH, bio sorbent dosage and biosorbent particle size. About 0.1g of bauhinia purpurea leaves was found to be enough to remove 84% of Congo red at concentration of 20 mg/L from 50 ml aqueous solution in 40 min. The optimumpH was found to be 6. The pseudo first order, pseudo second order and Elovich kinetic models were used to describe the kinetic data. The dynamic data was fitted with the pseudo second order kinetic model. The experimental equilibrium data were tested by the biosorption isotherms like Langmuir, Freundlich and Temkin and their equilibrium parameters were determined. The best fitted model to the experimental data for bauhinia purpurea leaves was Langmuir model.

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