Adsorptional photocatalytic mineralization of oxytetracycline and ampicillin antibiotics using Bi2O3/BiOCl supported on graphene sand composite and chitosan

Abstract

In present study, heterojunctioned Bi2O3/BiOCl (BO/BOC) was synthesized via in situ chemical reduction and oxidation of BiOCl nanoplates. BiOCl was reduced to metallic Bi in KHB4 solution followed by oxidation in H2O2 solution to produce BO/BOC. The BO/BOC was supported over graphene sand composite and also on chitosan using wet impregnation method to report BO/BOC/GSC and BO/BOC/CT nanocomposite. The morphology and compositional characteristics of BO/BOC/GSC and BO/BOC/CT were investigated by FESEM, TEM, HRTEM, FTIR, XRD, EDX, RAMAN, BET and UV-visible diffuse reflectance spectral analysis. The photocatalytic activity of BO/BOC/GSC and BO/BOC/CT was performed for mineralization of ampicillin (AMP) and oxytetracycline (OTC) antibiotics under solar light. The adsorption process had significant effect on photodegradation of AMP and OTC. The adsorption of both OTC and AMP onto BO/BOC/GSC and BO/BOC/CT followed pseudo second order kinetics. Simultaneous adsorption and degradation process (A+P) resulted in higher degradation rate of investigated antibiotics. The applicability of power law model indicates the intricacies of mineralization process. During A+P process, OTC and AMP were mineralized to CO2·H2O, NO3(-) and SO4(2-) ions. Both BO/BOC/GSC and BO/BOC/CT exhibited significant recycle efficiency.

Keywords: Adsorption; Antibiotic-mineralization; Bi(2)O(3)/BiOCl; Mineralization kinetics; Supported photocatalysts.