Dye removal using carbonized biomass, isotherm and kinetic studies

Abstract

Effect of thermal treatment on green tea dredge, an abundant waste, for dye removal was investigated in the present study. Variable temperature (800 and 900°C) and residence time in furnace (10 min, 1 and 2 h) were used to prepare six adsorbents which were characterized for surface morphology. The adsorption study was carried out using methylene blue as a model molecule and the effect of shaking time, pH and concentration was determined. Adsorbents prepared at 900°C were found to be more effective than those prepared at 800°C while longer residence time in furnace yielded adsorbents with higher adsorption capacity. The maximum adsorption capacity achieved in this case study was 71.4 ± 4.6 mg/g which is better than many activated carbons derived from other materials. Langmuir model was a better fit in isotherm studies while the sorption process followed pseudo-second-order kinetics.