Upcycling industrial plating effluent for rapid synthesis of Ag-decorated defective WO3 with enhanced photocatalytic activity

Abstract

A silver-containing industrial plating effluent was upcycled as silver source for synthesize Ag-decorated WO<inf>3</inf> catalysts for photocatalytic dye removal. WO<inf>3</inf> was first synthesized via acid precipitation and calcination, and subsequently decorated by silver species from plating effluent by photodeposition. Through the proposed procedure, the upcycled silver species were identified as Ag/Ag<inf>2</inf>S, resulting in the formation of Ag-WO<inf>3</inf> catalysts with enhanced light absorption capacity, increased defect density, and improved charge separation efficiency compared to pristine WO<inf>3</inf>. Content of Ag/Ag<inf>2</inf>S decorated on WO<inf>3</inf> surface played crucial role in enhancing the activity of WO<inf>3</inf> for methylene blue (MB) removal. Among all synthesized Ag-WO<inf>3</inf> catalysts, the 4.8 Ag-WO<inf>3</inf> sample demonstrated the highest photocatalytic efficiency, achieving over 99 % MB removal within 90 min under visible light irradiation. Photogenerated h⁺ and O<inf>2</inf>^•- exhibited an essential role in MB removal using the Ag-WO<inf>3</inf> catalysts. The results of this study highlight a promising and sustainable strategy for synthesizing the waste-derived, silver-based photocatalysts from industrial silver-containing wastewater. This approach aligns with the principles of green synthesis, offers strong potential for scalability, and supports the concept of a circular economy by promoting waste reduction through a simple, cost-effective method for addressing wastewater.