Tea Residue-Based Activated Carbon: Preparation, Characterization and Adsorption Performance of o-Cresol

In this study, the method regarding preparation of a tea residue-based activated carbon (AC) was provided. The physicochemical property and adsorption performance of the obtained AC were also investigated. The preparation of AC mainly includes the carbonization at 350 degrees C and activation by potassium hydroxide (KOH). The activation parameters including temperature, time and dosage of KOH are crucial to the physicochemical property of AC samples. According to the ANOVA analysis, the optimum activation conditions are determined as activation temperature of 900 degrees C, activation time of 60 min and mixture ratio of char and KOH of 3:2. The N(2)adsorption/desorption and scanning electron microscopy (SEM) characterizations confirm that AC obtained at the above-mentioned optimum activation conditions, designated as AC7, possesses well-developed porosity. The Langmuir model well describes the adsorption equilibrium ofo-cresol on sample AC7. The maximumo-cresol adsorption capacity obtained from the Langmuir model increases with the elevated temperature. The maximum adsorption capacity ofo-cresol on sample AC7 could reach up to 476 mg g(-1), which is higher than that of other reported AC samples. The adsorption kinetics ofo-cresol on sample AC7 follows the pseudo-second-order model. The generated pseudo-second-order rate constant ofo-cresol adsorption on sample AC7 rises with the operating temperature. The adsorption thermodynamics study shows thato-cresol adsorption on sample AC7 is spontaneous and endothermic. Apart from the physisorption, the chemisorption does exist betweeno-cresol and sample AC7. Particularly, the pi-pi dispersion interaction plays a dominant role duringo-cresol adsorption on sample AC7.