One step synthesis of chemically active carbon from tea residue for adsorptive removal of TDS

Abstract

Tea residue potential for elimination of total dissolved solids (TDS) from ground water was explored in its native form and also on its physical and chemical treatment to produce activated carbon. SEM and FTIR have been used to study the surface characteristics and functional groups of the adsorbent, respectively. The surface area was calculated by BETequation and adsorption conditions were optimized in terms of pH, temperature, amount of adsorbent and contact time. The maximalTDS removal has been observed at pH 4 with 0.8 g of adsorbent dosage and 60 min of contact time for the three adsorbent materials. Biosorption efficiency was found to increase with rise in temperature. Experimental results were examined using Langmuir and Freundlich isotherm models with data fitting satisfactorily to both isotherm models.Biosorption capacity was calculated as92.5, 101 and 120.5 mg/g for tea residue (TR), physically activated tea residue (PATR) and chemically activated tea residue (CATR), respectively. The kinetics data were studied using pseudo-first-order, pseudo-second-order and intraparticle diffusion equations data fitting well with pseudo-first-order for TR and pseudo-second-order for PATR and CATR. Gibbs free energy was observed to be spontaneous and enthalpy change value indicated endothermic nature of adsorption process.