Investigation of Phenol Adsorption from Aqueous Solutions Using Pomegranate Kernel Activated Carbon

This study has investigated the efficiency of pomegranate kernel activated carbon in phenol adsorption from aqueous solutions. Artificially samples of wastewater containing phenol in a laboratory scale were prepared with deionized water and the influences of effective parameters such as initial pH of the solution, adsorbent dosage, contact time, initial phenol concentration and the temperature were studied in a batch reactor. The residual phenol concentration in samples was determined with a spectrophotometer in 270 nm and the excel software was used for analyzing the experimental data. In order to kinetic study of phenol adsorption, the pseudo-first-order, pseudo-second-order, and intraparticle diffusion were chosen. The results showed that the data has the best fit with the pseudo-second-order model. Also, accordance of the data with the Langmuir and Freundlich isotherm models was investigated. The correlation coefficient value (R2=0.99) indicates that the adsorption followed the Freundlich isotherm model. Thermodynamic parameters such as standard Gibbs free energy (ΔGο), standard enthalpy (ΔHο) and standard entropy (ΔSο) was calculated in different temperature. Negative values of ΔGο and ΔHο demonstrate that the adsorption process is spontaneous and exothermic, respectively. The results showed the amount of phenol adsorbed increased when the contact time and adsorbent dosage increased and it was decreased with increasing the pH, phenol initial concentration and temperature. The maximum percentage of phenol adsorption on pomegranate kernel activated carbon in optimum condition (pH=2, adsorbent dosage=1.5 g, equilibrium time=30 minutes) in 100 mg/L initial phenol concentration was determined 94%. Based on the results of this study revealed that the pomegranate kernel activated carbon is a cheap and available adsorbent and has high potential to adsorption of phenol from aqueous solutions.