Synthesis and Photocatalytic Performance of ZnO-Impregnated Activated Carbon Derived from Oil Palm Fronds for Congo Red Degradation

Abstract

A ZnO-impregnated activated carbon (AC–ZnO) composite derived from oil palm fronds was successfully synthesized and exhibited high photocatalytic activity toward Congo Red degradation. Congo Red is a persistent azo dye frequently detected in textile wastewater and poses serious environmental and health risks. This study aims to synthesize ZnO-impregnated activated carbon derived from oil palm fronds and to evaluate its photocatalytic performance for Congo Red degradation under UV irradiation.  Activated carbon was prepared from oil palm fronds and impregnated with ZnO using a wet impregnation method with ZnO loadings of 5–25% and impregnation times of 6 and 12 h, followed by calcination at 400 °C. The composite materials were characterized by FTIR, XRD, and UV–DRS. Photocatalytic activity was assessed using a 10 ppm Congo Red solution and catalyst dosages of 25–75 mg under UV light. The highest degradation efficiency of 93.87% was achieved using 75 mg AC–ZnO with 15% ZnO loading and 6 h impregnation time. Enhanced performance was attributed to the synergistic effect between adsorption by activated carbon and photocatalytic oxidation by ZnO. The biomass-derived AC–ZnO composite demonstrates strong potential as a sustainable and low-cost photocatalyst for the treatment of dye-contaminated wastewater.