Solar-driven photodegradation of phenol using reusable photocatalytic pottery plates synthesized from Claus process waste

Abstract

Phenol, a toxic environmental contaminant, poses significant risks to ecosystems and human health, necessitating effective remediation strategies. This study explores the solar-driven photodegradation of phenol using photocatalytic pottery plates synthesized from industrial waste generated by the Claus process. The Ag-TiO₂ photocatalysts were successfully synthesized and immobilized on pottery plates, as confirmed by comprehensive characterization techniques, including XRF, BET, UV–Vis DRS, PL, SEM, EDX Mapping, FTIR, XRD, and EIS. These analyses revealed the high purity, anatase phase, and efficient electron-hole separation of the Ag-TiO₂ photocatalyst, contributing to its superior photocatalytic performance. Under optimal conditions: pH 7.2, an immobilized Ag-TiO₂ loading of 3.5 mg/cm², and an initial phenol concentration of 50 mg/L, the system achieved a maximum phenol removal efficiency of 91 % after 180 min of solar irradiation. Kinetic studies confirmed that the degradation process follows the Langmuir-Hinshelwood isotherm model, with a high adsorption constant (1.362 L mg⁻¹) and + 7.281 mg/L min⁻¹ for KC indicating strong phenol adsorption onto the catalyst surface and rapid photochemical reaction following adsorption. The photocatalyst demonstrated excellent reusability, maintaining 86.5 % efficiency over five cycles without significant loss of activity. Hydroxyl radicals (^•OH) were found to be the dominant reactive species driving phenol degradation. These findings highlight the potential of waste-derived photocatalytic pottery plates for sustainable and efficient phenol removal under solar irradiation, offering a green and cost-effective solution for treating phenolic wastewater, particularly in sun-rich regions.