Kinetic and thermodynamic investigations on removal of toxic dye using chemically activated tecoma stans seed pods

摘要

A novel biomaterial which is of low cost, easily available and eco-friendly was identified from the seed pods of tecoma stans shrub. It was chemically activated using sulphuric acid and the resulting carbonaceous material was characterized by FTIR, SEM and BET Analysis. Its potential was investigated for the removal of methyl green dye. Batch mode studies were performed to optimize the reaction control variables such as temperature, pH, adsorbent dosage, adsorbent particle size, initial dye concentration and agitation time. The data obtained was analysed for best performance of the adsorbent. These examinations have led to the surface modifications of the adsorbent using iron oxides. Batch mode studies have proved maximum dye adsorption of 97.3% at pH 6 for a nominal adsorbent dose of 0.001 g/ml at room temperature. Isotherm investigation proved multilayered adsorption of the dye with the maximum adsorption of 158.74 mg/g. Kinetic modelling of the data for different concentrations confirmed pseudo second order mechanism. Thermodynamic parameters were evaluated and negative values of ΔG and ΔH proved exothermic nature of adsorption. Desorption studies were also performed to examine the regeneration capacity of the adsorbent.