Cr(VI) removal from synthetic textile effluent using Tamarindus indica bark: a kinetic and thermodynamic study

摘要

Discharge of untreated textile effluents containing heavy metals is a serious environmental issue. Biosorption is a promising method for the removal of heavy metals. The present study analyses the biosorption of Cr(VI) from synthetic textile effluent onto tamarind bark biomass as a function of initial metal ion concentration, contact time, pH, sorbent dosage, shaking speed and temperature. The optimum pH and temperature are found to be 2 and 20 degrees C respectively. The maximum biosorption capacity q(e) is 21.001 mg/g. Freundlich isotherm model fitted well with correlation coefficient of 0.9. Kinetic study reveals that the biosorption of Cr(VI) follows a pseudosecond-order model. The biosorption of Cr(VI) is spontaneous and exothermic as shown by negative free energy change (Delta G(0)) and negative enthalpy (Delta H-0). Desorption experiments with 2M NaOH, infer the reusability of the biomass up to five times with high efficiency.