Heterogeneous UV–Fenton Process by Maize-Straw-Templated TiO2/Fe3O4 for the Degradation of Tetracycline: Optimization Using Response Surface Methodology

The heterogeneous Fenton-like catalysts TiO2/Fe3O4 were fabricated using maize straw as template (MST-TiO2/Fe3O4) by calcination followed by the hydrothermal method. The characterization showed that higher Fe3O4 particle dispersion, closer interaction between TiO2 and Fe3O4, stronger electron transfer ability, and lower leaching of Fe ions of MST-TiO2/Fe3O4 catalyst resulted in higher catalytic activity towards the degradation of tetracycline (TC) compared to pure Fe3O4. The best conditions for TC degradation were initial pH = 6.74, 11.52 mmol/L of H2O2, 0.38 g/L of MST-TiO2/Fe3O4, and a reaction time of 56.63 min according to the response surface methodology (RSM) result based on the Box–Behnken design (BBD). The quadratic model was well-fitted to the experimental data with R2 (0.9843) and adj-R2 (0.9660) by the analysis of variance (ANOVA). Under the optimum reaction conditions, a maximum removal rate of 98.67% was achieved. The findings of the present study revealed that heterogeneous UV–Fenton process catalyzed by MST-TiO2/Fe3O4 was a suitable way for the degradation of TC from aqueous environment.