Efficient degradation of cefotaxime by a UV+ferrihydrite/TiO2+H2O2 process: the important role of ferrihydrite in transferring photo-generated electrons from TiO2 to H2O2

Background Developing effective removal processes for antibiotics has attracted increasing interest recently. In this work, a novel strategy involving the combination of photocatalysis with Fenton reaction using ferrihydrite/TiO 2 (Fh/TiO 2 ) nanohybrids was developed to efficiently degrade the antibiotic cefotaxime. Fh/TiO 2 nanohybrids were synthesized by simply growing Fh on the surface of commercially available TiO 2 . We expected that Fh of Fh/TiO 2 could capture photo-generated electrons from TiO 2 , inhibiting the recombination of electron–hole pairs; also, by virtue of Fe(III)/Fe(II) cycle on Fh/TiO 2 , photo-generated electrons could be continually transferred to H 2 O 2 to produce ·OH. Accordingly, high degradation efficiency of cefotaxime could be achieved. Results With UV light and H 2 O 2 , Fh/TiO 2 with a Fe/Ti molar radio of 7% showed high catalytic activity indeed, and its degradation rate for cefotaxime was nearly three times higher than that of TiO 2 . The decomposition of H 2 O 2 and production of ·OH in the UV+7%Fh/TiO 2 +H 2 O 2 system were also increased markedly. The large amount of Fe(II) on 7%Fh/TiO 2 determined in this system supported our hypothesis that Fh of 7%Fh/TiO 2 could capture photo-generated electrons from TiO 2 . Although dissolved iron was observed, the contribution of Fenton reaction by dissolved iron was rather limited. After four consecutive cycles, 7%Fh/TiO 2 still retained good stability. Conclusions The UV+7%Fh/TiO 2 +H 2 O 2 system provides a potential alternative in degradation of cefotaxime for further practical application, and it has the following advantages: high catalytic activity, simple preparation method, good stability and low cost, as well as continued catalytic activity after total consumption of H 2 O 2 . © 2019 Society of Chemical Industry