The persistence of water-soluble polymers such as polyvinylpyrrolidone (PVP) in aquatic environments presents a major challenge for conventional wastewater treatment. Herein, a sunlight-active TiO2/activated carbon (TiO2/AC) composite fabricated via a simple physical mixing route is reported for the synergistic adsorption and photocatalytic mineralization of PVP K30. The optimal composite (2:1 weight ratio) exhibits a high surface area (412 m2 g−1) and an integrated anatase–carbon architecture. The process operates through a sequential “adsorb-and-shuttle” mechanism, whereby PVP is first concentrated on the composite in the dark (30.2% removal in 8 h) and subsequently degraded under solar irradiation. This dual function leads to 86.4% PVP removal and 72.1% total organic carbon (TOC) mineralization, demonstrating true polymer destruction rather than mere surface accumulation. The composite demonstrates robust performance in simulated wastewater, retaining over 68% PVP removal and 55% TOC mineralization in a complex matrix containing competing inorganic ions and natural organic matter. Spectroscopic and thermogravimetric analyses confirm PVP chain scission and near-complete removal of adsorbed residues. An optimized ethanol-washing protocol enables effective catalyst regeneration, with the composite retaining 85% of its initial activity after five cycles. A detailed techno-economic analysis confirms the economic viability of this regeneration strategy at industrial scales (>1000 kg/year), projecting cost savings exceeding 60% compared to fresh catalyst use. Importantly, the PVP-loaded spent TiO2–AC was successfully repurposed as an electrocatalyst for the urea oxidation reaction, achieving a high current density of 163.7 mA cm−2, which surpasses the performance of the pristine composite. The greenness of the overall process was validated using analytical eco-scale (ESA), method volume intensity (AMVI), and white analytical chemistry (WAC) metrics. Overall, this work presents a sustainable, solar-driven platform that advances a circular economy model, integrating effective polymer wastewater remediation with subsequent energy valorization of the spent material.
Mahgoub et al. (Sat,) studied this question.