Efficient photocatalyst based on activated carbon/graphene oxide/TiO2 synthesized under acidic conditions for environmental remediation

Abstract

Efficient materials are needed to address water contamination by pharmaceuticals, a growing environmental concern. Sulfamethazine (SMT), a widely used antibacterial, frequently contaminates freshwater ecosystems due to its high excretion in unchanged form during infection treatments. This study investigates a photocatalyst combining activated carbon (AC), graphene oxide (GO), and titanium dioxide (TiO₂) for SMT degradation. Among the prepared materials, AC/GO/TiO₂ synthesized under acidic conditions (pH 4) achieved 95 % degradation of SMT within 80 min under UV light irradiation. This performance is attributed to its high surface area (170 m²/g), efficient electron transfer, and reduced electron-hole recombination. Acid treatment significantly enhanced the interaction between TiO₂ and the AC/GO matrix, as evidenced by SEM-EDS and XPS analyses, which revealed the formation of Ti–O–C bonds. Structural characterization through XRD, Rietveld refinement, and Raman spectroscopy confirmed the pure anatase phase with consistent crystalline domain sizes (∼13.7 nm), which is essential for sustained photocatalytic activity. Despite surface saturation during adsorption cycles, the photocatalyst maintained its structural integrity and degradation efficiency over four consecutive cycles, retaining its anatase crystallinity and Ti content. These results underscore the high stability, reusability, and effectiveness of synthesized material in degrading pharmaceutical contaminants. AC/GO/TiO₂-prepared in acid conditions emerges as a promising candidate for wastewater treatment, industrial effluent management, and advanced oxidation processes, offering a sustainable water resource management and environmental protection solution.