Optimization of microwave sol-gel synthesis of N-Ce-AC/TiO₂ for adsorption/ photodegradation of tetracycline

Nitrogen (N) and cerium (Ce) co-doped titanium dioxide (TiO2) supported activated carbon (AC) (N-Ce-AC/TiO2) were synthesized to remove antibiotic tetracycline from aqueous solution via adsorp-tion and photodegradation. The sol-gel technique, aided by microwave radiation, was used to syn-thesize N-Ce-AC/TiO2. Central composite design under response surface methodology was used to optimize the variables comprising urea (N source) (A: 0.02-0.20 g), cerium(III) nitrate hexahydrate (Ce source) (B: 0.02-0.20 g), activated carbon (C: 0.10-0.50 g), and microwave power (D: 600-800 W), where the degradation of tetracycline was the response. Characterization of the produced cata-lyst was carried out by means of X-ray diffraction, scanning electron microscopy, energy-disper-sive X-ray spectroscopy, and the Brunauer-Emmett-Teller method for determining surface-texture parameters. N-Ce-AC/TiO2 prepared with 0.50 g activated carbon, doped with 0.02 g urea and 0.20 g cerium, and activated at microwave power 600 W for 15 min exhibited 91.08% tetracycline removal when subjected to 7 W of UV irradiation, according to the results of optimal variable preparation.