Enhanced photocatalyst with TiO2-anchored iron tailings structure for highly efficient degradation of doxycycline hydrochloride

The low utilization of sunlight and fast recombination of photogenerated electron-hole pairs (e−/h+) are the main reasons preventing the wide application of titanium dioxide (TiO2) in photocatalysis. A novel hybrid composite of TiO2/iron tailings (TITs) was synthesized in this study via a facile method as a photocatalyst for the degradation of doxycycline hydrochloride (DOX). The design beneficially enhances the light absorption capacity because the TITs composite photocatalyst has a narrower band gap (2.77 eV), larger light absorption edge (448 nm), and restrains recombination of photogenerated e−/h+, which is attributed to the TITs composite photocatalyst having a lower photoluminescence (PL) strength, a higher transient photo-current response, and a smaller Nyquist plot radius, as compared with pure TiO2. The DOX removal efficiency by TITs during photocatalytic degradation was 98.37% within 120 min under a Xe lamp and 76.73% within 180 min under sunlight, which were 1.23- and 1.46-fold higher than that of pure TiO2, respectively. The DOX removal rate increased by 3.8-fold after swine wastewater was diluted 20 times. This study provides an economical method for the clean recycling of iron tailings and identifies cheap raw materials for the preparation of photocatalytic materials, reducing the cost of photocatalytic materials applied to wastewater treatment, which is helpful for promoting the practical application of TiO2-based photocatalysts.