Deep remediation of oil spill based on the photocatalytic degradation of solar light-driven floating C-doped TiO2/Sepiolite composites

Abstract

This study developed a novel C-doped floating-type TiO₂/sepiolite composite. C-TiO₂/Sep composites were synthesized using various carbon sources (glucose, acetic acid, acetylacetone) through a simple hydrothermal method, with a Ti to C molar ratio of 5 and a Ti to sepiolite ratio of 40 mmol/g. The floatable composites were obtained via hydrophobic modification using a stearic acid to product ratio of 0.7 mmol/g. The resulting composites were characterized using XRD, SEM, PL, XPS, and UV–vis. The results indicate that the chemical and morphological properties of the composites are significantly affected by the carbon source. Compared to undoped samples, the C-doped samples exhibit improved anatase phase stability and reduced grain sizes. The incorporation of C is predominantly exhibited as C-O-Ti-O, and the surfaces of the samples are modified with carbon photosensitizers. PL spectra and photocatalytic activity tests under visible light reveal that the CTHS-GLU (Hydrophobic Sepiolite with Carbon-Doped TiO₂ Using Glucose as the Carbon Precursor) sample achieved an 80.78 % oil removal rate, demonstrating the best efficiency in oil spill remediation, which is attributed to C-doping’s reduced band gap, high adsorption capacity, uniform TiO₂ distribution, and enhanced surface hydrophobicity.