Photoactivation and photoregeneration of TiO2/PAC mixture applied in suspension in water treatments: approach to a real application

The process TiO 2 /PAC/UV-vis has been under study and compared with the isolated treatments of adsorption and photocatalysis determining possible synergies between adsorption and photocatalysis of target antibiotics: amoxicillin, enrofloxacin, sulfadiazine, and trimethoprim. The characterization of the TiO2/PAC mixture was carried out via FESEM and FTIR. Moreover, a kinetic study has been performed. The effect of UV-vis radiation and the type of matrix was analyzed in TiO 2 /PAC/UV-vis process. The performance of this treatment has been monitored during three cycles, evaluating also the regeneration of TiO 2 /PAC mixture by UV-vis light. TiO 2 /PAC/UV-vis process allowed the removal of the antibiotics in the range 90–100% (an average removal of 93% of the initial concentration) after 60 min of treatment. However, only amoxicillin showed a significant synergy applying TiO 2 /PAC/UV-vis process. Regarding matrix effect, no influence of the matrix type (ultrapure water or treated wastewater) was observed. Since PAC tends to be deactivated gradually, the TiO 2 /PAC/UV-vis process performance decreases after each cycle in a 15% average. Finally, regeneration via UV-vis light started to be effective after a total of 4 h of regeneration.