Production and optimisation of adsorbent materials from teawaste for heavy metal removal from aqueous solution: feasibility of hexavalent chromium removal – kinetics, thermodynamics and isotherm study

Abstract A face-centred central composite experimental design scheme was used to find conditions this would result in producing magnetic bleached teawaste (MBTW) adsorbent material have the optimum hexavalent chromium (Cr(VI)) removal capacity. The effect of treatment conditions, namely temperature (200 °C, 350 500 °C), duration heat (2 h, 3 4 h), concentration iron chloride (0.02 g/g, 0.055 0.09 g/g) added investigated. results obtained showed that pyrolysis and amount during had significant effects on performance MBTW both total Cr(VI). Increasing from 200 °C Cr(VI) Cr decrease. with for detailed adsorption study. study indicated has an excellent Langmuir capacity (269.9 mg/g). process also involved reduction Cr(III). shown be temperature-dependent endothermic. According FTIR analysis kinetic modelling results, chemisorption is main mechanism responsible background ions investigated show presence carbonate caused a huge while least effect.