Efficiency of low-Ag-content biosynthesized ZnO/Ag on photodegradation of paracetamol

Abstract

Photocatalysis technology is gaining interest as an alternative wastewater treatment due to its fast and complete pollutants removal advantages. It utilizes light energy and semiconductor catalysts to degrade organic pollutants such as paracetamol (PCM), a common household medication drug. Pharmaceutical wastewater may cause significant hazards to humans and the environment if no advanced treatment is applied. In this study, zinc oxide/silver (ZnO/Ag) nanocomposite was biosynthesized using banana peel extract (BPE) and low Ag content (1 mM and 3 mM) as biomaterial via sol-gel and precipitation for photocatalytic degradation of PCM. Fourier Transform Infrared Spectrophotometer (FTIR) analysis showed a sharp peak of Zn-O band for all catalysts with the success of BPE incorporation. The band gap energy of ZnO/Ag was 3.281 eV, increasing with Ag content. Field Emission Scanning Electron Microscope (FESEM) images of ZnO/Ag exhibit a smaller size of 29.49 nm and a distinct spherical shape. The uniform shape of biosynthesized ZnO/Ag confirms the roles of BPE as stabilizing and capping agents. The highest photocatalytic degradation of PCM was 76% with a reaction constant of 0.0086 min-1 when ZnO/Ag was used as a catalyst, compared to the pristine ZnO was 70%. The as-prepared ZnO/Ag nanocomposite from organic solid waste has a high potential for being reutilized as an advanced catalyst for pharmaceutical wastewater treatment.