Evaluation of biosorption potential of Gracilaria corticata for the removal of malachite green from aqueous solution: isotherm, kinetic and thermodynamic studies

摘要

In the present study, the protonated Gracilaria corticata (PGC) biomass has been successfully used as biosorbent for the removal of malachite green (MG) from aqueous solution. The biosorbent was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), elemental analysis, pHpzc, and Boehm titration, respectively. The degree of MG biosorption was investigated as a function of pH, adsorption time, biosorbent concentration, initial dye concentration, agitation rate and temperature. The maximum biosorption of MG was observed at the biosorbent concentration of 0.1 g/L, initial pH 10, temperature 30 degrees C, agitation rate 150 rpm, and initial dye concentration of 100 mg/L. Various isotherm models were used to evaluate the equilibrium data obtained. The equilibrium data best fitted with Langmuir model with highest coefficient of determination 0.994. The Langmuir monolayer biosorption capacity was recorded as 100 mg/g. In addition, study of RL, the dimensionless factor revealed the favorability of the isotherm. The kinetic data were well described using pseudo-second-order kinetic model. Thermodynamic profile indicated the biosorption of MG is favorable and spontaneous in nature. The reusability of the PGC biomass was investigated using 0.1 M HCl. Attempts were also made to study the continuous biosorption in up-flow packed bed column. Overall, the present study proved that, PGC biomass can be effectively used as biosorbent for the removal of MG bearing wastewater.