Ball-milled titanium-modified biochar for the removal of dimethyl phthalate from aqueous solutions.

Dimethyl phthalate (DMP), a widely occurring organic pollutant in water bodies, has attracted considerable attention for its hazards. In this research, using Suaeda glauca biochar (SGBC) as a carrier, a series of TiO₂/SGBC composites were prepared via ball milling and their photocatalytic performance for DMP degradation was evaluated. A TiO₂ loading of 40% (40%-TiO₂/SGBC) yielded a 93.2% DMP degradation efficiency under visible light irradiation a pH = 9, a catalyst dosage of 0.5 g/L, and an initial DMP concentration of 20 mg/L. Ball milling increased the specific surface area and pore volume of the material and promoted the uniform dispersion of TiO₂ nanoparticles on the biochar surface, forming a stable heterostructure. Photoelectrochemical tests demonstrated that the composite material exhibited favorable photogenerated charge separation and transport properties. Free radical quenching experiments and electron paramagnetic resonance (EPR) analyses confirmed that ·OH, ¹O₂, and ·O₂⁻ played synergistic roles in the degradation process. Toxicity assessment further indicated that the inhibitory effects of DMP solution on rice seed germination and seedling growth were reduced by 40%-TiO₂/SGBC. This study provides a feasible strategy for the high-value utilization of waste biomass resources and the efficient removal of phthalate pollutants from aquatic environments.