2Yildiz Technical University, Environmental Engineering Department, 34220 Esenler, Istanbul, TURKEY
Abstract
Phenol is the 11th most toxic 126 chemical substance and causes cancer by accumulating in the food chain. Adsorption of phenol is an effective and also environmentally friendly method for its removal. In this study, phenol removal by using powdered activated carbon (PAC) was optimized and modeled for various isotherms at constant mixing rate (150 rpm) and sample volume (100 mL); adsorbent dose (0.01-2 g), contact time (1-180 min), and initial phenol concentration (50-1000 mg L-1). Moreover, adsorption studies were carried out at different temperatures for kinetic and thermodynamic calculations. In this study, optimum adsorbent dose and contact time of PAC were determined as 0.3 g 100 mL-1 (3 g L-1) and 10 minute, respectively. It can be concluded that it provides discharge standards for a wastewater containing 100 mg L-1 phenol. It was observed that the adsorption capacity decreased with increasing temperature and the adsorption process fits well with Langmuir isotherm. It has been concluded that the adsorption of phenol with PAC is an exothermic reaction. As a result of the kinetic studies, it was found to be suitable for the Pseudo Second Order (R2 0.9999-1.0000). ∆S, ∆H and ∆G were calculated as -0.02 J mol-1 K-1, -14.15 kJ mol-1 and between -8.16 and -7.76 kJ mol-1, respectively.