Adsorption photocatalysts of carbon-entrained and roasted bentonite carrier for Ag3PO4 in efficient removal of antibiotics

Abstract

Bentonite was modified by carbon-entraining and roasting method (marked as C.R-bentonite) and Ag3PO4 was successfully loaded on the C.R-bentonite by ultrasonic assisted precipitation method. The composition, morphology, structure and optical property of the composite were investigated using FT-IR, XRD, XPS, N2 adsorption–desorption, SEM, HRTEM, UV-Vis-DRS, and PL spectra. The obtained Ag3PO4/C.R-bentonite composite show enhanced adsorption photocatalytic efficiency for the removal of norfloxacin under visible light irradiation compared with pure Ag3PO4, and the Ag3PO4/C.R-bentonite composite catalyst with 20% content of Ag3PO4 showed the highest removal rate of 93.71% under the optimal reaction condition. Besides, the better stability is also gained after three cycles. The enhanced performance is attributed to Ag3PO4 uniformly dispersed on the surface or entered the pores of C.R-bentonite, high-efficiency separation of photogenerated electron-hole pairs and enlarged specific surface area. Furthermore, reactive species trapping experiments confirmed that holes and •O2− played crucial roles in the photocatalytic process. And the high degradation efficiency of other two antibiotics shows the good universal application. This paper displays the potential to provide a high-efficiency as well as cost-effective adsorption photocatalyst for antibiotics removal.