ZnO-doped kaolin nanoclay immobilized agar biopolymer for 2,4-dinitrophenol photocatalytic degradation

Abstract

This study focuses on enhancing the properties of kaolin (Kao) clay by incorporating Zinc oxide nanoparticles (ZnO NPs) and further functionalizing with agar biopolymer, resulting in the formation of Agar/Kao@ZnO nanocomposite (NC). The synthesized material underwent comprehensive composition, structure, surface, and optical properties analysis to confirm the formation. The material was evaluated as a photocatalyst for the degradation of 2,4-dinitrophenol (DNP) under visible light irradiation. The optimized conditions for the photocatalytic degradation of DNP were determined as irradiation time 50 minutes, pH 4, catalyst dose 20 mg, and DNP concentration of 25 mg L⁻¹, resulting in degradation efficiency of 99.63%. Trapping experiment validated the significant role of hydroxyl (^•OH) radicals as reactive oxidant species (ROS) in the degradation of DNP in the presence of visible light. Through four consecutive cycles of reusability experiments, it was confirmed that the synthesized material is highly stable and efficient for DNP degradation.