Enhanced photocatalytic degradation of organic pollutants using a TiO2–clay nanocomposite in a rotary photoreactor with experimental and theoretical insights

Authors:
Open Access
Publisher website
Google Scholar
Abstract
Water pollution from synthetic dyes poses a serious environmental challenge due to their persistence, toxicity, and resistance to conventional treatment methods. To address this issue, we designed a novel rotary photoreactor employing a titanium dioxide–clay (TiO2–clay) nanocomposite immobilized with silicone adhesive for efficient photocatalytic degradation. The optimized TiO2–clay composite (TiO2/clay = 70:30) exhibited an enhanced BET surface area of 65.35 m2/g compared to 52.12 m2/g for pure TiO2. The point of zero charge (PZC) was determined to be pH 5.8, favoring adsorption of the cationic BR46 dye under near-neutral pH conditions. Under optimal operating parameters—20 mg/L initial dye concentration, 5.5 rpm rotation speed, and 90 min of UV exposure—the system achieved 98% dye removal and 92% total organic carbon (TOC) reduction. Kinetic analysis confirmed a pseudo-first-order model (R2 > 0.97) with an apparent rate constant of 0.0158 min–1. Radical scavenger experiments identified hydroxyl radicals (OH·) as the primary oxidative species, consistent with Density Functional Theory (DFT) predictions. GC–MS analysis further verified the degradation of BR46 into non-toxic intermediates. The TiO2–clay nanocomposite demonstrated excellent stability and reusability, maintaining > 90% efficiency after six cycles. These findings underline the potential of the TiO2–clay rotary photoreactor as a robust and sustainable technology for advanced wastewater treatment.

This publication has 76 references indexed in Scilit: