Removal of Cr(VI) from aqueous solution using tea waste loaded CeO2 nanoparticles

Abstract

A novel bio-adsorbent, tea waste/CeO2 bio-composite was synthesized by precipitation process. Batch adsorption study was conducted to investigate the ability of the material for the rapid removal of Cr(VI). Dependence of adsorption on adsorbent dose, pH of the solution, contact time, and temperature had been studied to achieve the optimum condition. The characterization of the bio-adsorbent and mechanisms of Cr(VI) adsorption on the material were studied by using XRD, SEM, FESEM, TEM, BET and FTIR. The analysis of the results indicated that Cr(VI) was adsorbed on the bio-composite surface in just 30 min and was highly pH dependent. The Langmuir isotherm model was best consistent with the experimental data with maximum adsorption capacity of 8.51 mg/g at pH 3, The adsorption kinetics of Cr(VI) at different time interval obeyed pseudo-second-order rate equation. The removal efficiency of the bio-composite was high even in presence of other co-anions. The exhausted tea waste/CeO2 bio-composite was regenerated with NaOH solution and removal rate was up to 85% after four consecutive cycles. The above results reveals that the tea waste/CeO2 bio-composite is environmental friendly, can be used as an adsorbent for removal of Cr(VI) from wastewater.