Enhanced photocatalytic degradation via light–pollutant decoupling in a dual-channel α-Fe2O3/TiO2 reactor

Photocatalytic treatment of wastewater is often limited by insufficient light penetration caused by pollutants and inefficient catalyst recovery. To address these challenges, a novel dual-channel photocatalytic reactor (DCPR) based on an α-Fe₂O₃/TiO₂ film was developed. In this system, light propagates through an independent transparent channel, while pollutants and oxygen flow through a separated reaction channel, enabling enhanced light utilization and improved interaction between reactants and photocatalytic interfaces. The results demonstrate that the dual-channel configuration significantly enhances photocatalytic performance. The degradation rate of methylene blue was 3.65 times higher than that of a conventional single-channel reactor. Under optimized conditions, the phenol degradation efficiency reached 93.05% after 12 h of visible-light irradiation, accompanied by a total organic carbon (TOC) removal efficiency of 71.3%. The α-Fe₂O₃/TiO₂ catalyst film exhibited excellent reusability, maintaining approximately 90% of its degradation efficiency after ten consecutive cycles. Furthermore, the practical applicability of the DCPR system was evaluated using a synthetic industrial wastewater matrix containing phenol, humic acid, and inorganic salts. The reactor maintained continuous degradation capability under this complex wastewater condition, demonstrating its potential for practical wastewater treatment applications. Mechanistic investigations revealed that superoxide radicals (·O₂⁻) and photogenerated holes (h⁺) were the dominant reactive species involved in the degradation process, while hydroxyl radicals (·OH) played a secondary role. The enhanced photocatalytic performance was attributed to the separation of light and pollutant transport pathways, which effectively reduced light attenuation and promoted mass transfer. This study provides an effective reactor design strategy for improving photocatalytic efficiency and offers a promising approach for the treatment of complex wastewater matrices.