ZnO Nanoparticles Deposited on Gamboge (Garcinia gummi-gutta L.) Based Activated Carbon for Removal of Phenol from Synthetic Wastewater

Abstract

This study was performed to investigate the potential utilization of Gamboge in the green synthesis of ZnO nano particles (NPs) and production of activated carbon (AC) in order to explore both ZnO NPs and Gamboge based AC for the removal of phenol from synthetic wastewater. Aqueous extracts of dried fruits of Garcinia gummi-gutta L. were used for the synthesis of ZnO NPs and formation of NPs was confirmed by the characteristic absorption peak at 364 nm in the UV-Vis spectroscopic analysis. X-ray diffraction pattern confirmed a well crystallized hexagonal wurtzite structure of ZnO NPs. Gamboge based activated carbon (AC) samples were prepared using two activating agents: ZnCl2 and H3PO4. Deposition of NPs on AC was confirmed by X-ray diffraction analysis. Photo catalytic degradation ability of synthesized NPs and NPs deposited AC was studied for the removal of phenol from synthetic phenol solution. The present study revealed that, incorporation of AC produced by activation with ZnCl2 into ZnO NPs has enhanced the removal efficiency of phenol by 12%. The effect of experimental parameters such as pH, contact time, dosage and initial phenol concentration on degradation of phenol was studied. It was revealed that NPs loaded onto ZnCl2/AC have higher degradation ability (94.23%) for phenol when compared with NPs loaded onto H3PO4/AC (81.72%) at optimized experimental conditions. The highest phenol degradation efficiency was observed under optimum conditions of pH 6.9, dosage of 3.0 g L-1 and initial phenol concentration of 100 mg L-1 in natural sunlight for 6.00 h. It is evident that the intensity of sunlight which was measured using the Lux meter plays a major role in photo catalytic degradation of phenol. This research opens a new path to enhance photo catalytic degradation of phenol in which both NPs and ACs are used.