Study on adsorption of methyl orange by waste tea

Abstract

The adsorption effect of waste tea leaf on dye methyl orange was studied. The tea after decolorization for 6 h was modified with potassium permanganate, and then the adsorption properties of unmodified and potassium permanganate modified tea to methyl orange were studied. The influence of the optimal pH value, dosage of unmodified and modified tea, initial concentration of methyl orange, adsorption temperature and contact time variables of methyl orange and tea powder on the adsorption performance was obtained in the experiments. Under the optimized conditions, the maximum adsorption rate of potassium permanganate-modified tea leaves was 99.82 %, and the maximum adsorption capacity was 3.9928 mg/g. The kinetics, thermodynamics and adsorption properties of methyl orange by KMnO4 activated tea and unmodified teas were studied. The adsorption kinetics results showed that the adsorption was in accordance with the pseudo-second-order kinetic equation. The adsorption thermodynamics results showed that the adsorption process was exothermic and the entropy decreased. The research results of adsorption isotherms showed that the adsorption process was in accordance with the Freundlich adsorption isotherm. Scanning electron microscopy, X-ray diffraction and infrared spectroscopy were used to characterize KMnO4 activated tea powder samples. This method can adsorb methyl orange, reduce the concentration of methyl orange in wastewater and the damage to the environment.