Removal of acetaminophen from aqueous solution by using activated carbon derived from spent tea leaves

Abstract

This study is about the removal of acetaminophen from aqueous solution by using activated carbon derived from spent tea leaves. Activated carbon was prepared by using phosphoric acid as chemical activating agents. The characteristics such as functional group, surface areas, pore volume, and morphology of activated carbon treated with H3PO4 (ACH) were identified by using Fourier Transform Infrared Spectroscopy (FTIR), Brunauer-Emmett- Teller (BET) and Field Emission Scanning Electron Microscopy (FESEM). The total surface areas and pore volume of ACH were 1,202.836m2/g and 0.720cm3/g, respectively. The effect of contact time, initial concentration, adsorbent dosage, pH and temperature were studied during the adsorption process. The highest removal percentage, 99.87% was achieved in the condition of initial concentration, adsorbent dosage; pH and temperature were 10 mg/L, 0.5g, pH 3 and ±25ºC, respectively. To describe the equilibrium isotherm of adsorption, the experimental data were fitted into Langmuir and Freundlich isotherm models. The equilibrium data was followed to the Langmuir isotherm with the maximum capacity of 57.16 mg/g. Pseudo-first order, pseudo-second order and intraparticle diffusion kinetic models were used to analyze the kinetic equilibrium of adsorption process. The adsorption process of acetaminophen was followed Pseudo-second order kinetic. Negative values of ΔGº (-1.1323 to -0.5071 kJ mol-1), ΔHº (-10.5754 kJ mol-1) and ΔSº (-31.0786 J/mol.K) indicated that the adsorption process of acetaminophen was feasible, spontaneous and exothermic in the condition of experiment. Based on the result, it can be concluded that activated carbon derived from spent tea leaves can be employed as low-cost activated carbon and remove acetaminophen from aqueous solution effectively.