Adsorptional photocatalytic mineralization of ampicillin and oxytetracycline antibiotics utilizing BiOCl based nanocomposites Thesis

Abstract

Abstract newlineSchool of Chemistry xiv newlineAbstract newlineSupported photocatalytic systems have been used to overcome the inherent limitation of bare metal oxides semiconductors which involves agglomeration and low removal efficiency. The photocatalytic degradation generate the most powerful oxidizing agent i.e. hydroxyl radicals through illumination with visible light that has been proven to be the most effective pollutant removal method. The quicker separation of supported photocatalyst is the striking feature of supported photocatalytic system. newlineIn precedent work, WO3/BiOCl, heterojunction Bi2O3/BiOCl (BO/BOC) and nano-sized BiOCl were immobilized onto graphene sand composite (GSC) and chitosan (CT) to report efficient supported photocatalytic system for wastewater treatment. The simple modified hydrolysis method was used to report BiOCl, WO3/BiOCl photocatalytic system and in situ chemical reduction and oxidation to prepare for BO/BOC. Common sugar and river sand were used as precursor for the preparation of GSC. The effective mineralization of antibiotics, oxytetracycline (OTC) and ampicillin (AMP) using BiOCl, Bi2O3/BiOCl (BO/BOC) and WO3/BiOCl photocatalyst stacked to graphene sand composite (GSC) and chitosan (CT) was investigated. The morphology and compositional characteristics of synthesized BiOCl/GSC, BiOCl/CT, BO/BOC/GSC, BO/BOC/CT, WO3/BiOCl/GSC and WO3/BiOCl/CT photocatalysts were investigated using FESEM, TEM, HRTEM, EDX, FTIR, XRD, FT-RAMAN, BET, PL and UV-Visible reflectance spectral analysis. The optical band gap of BiOCl/GSC, BiOCl/CT, BO/BOC/GSC, BO/BOC/CT, WO3/BiOCl/GSC and WO3/BiOCl/CT system were 3.31, 3.33 eV, 3.2 eV 2.86 and 2.84 eV, respectively. Synthesized photocatalytic system exhibited significant photocatalytic activity for mineralization of OTC and AMP under solar light. The adsorption process had significant effect on photodegradation of AMP and OTC was described by pseudo second order kinetics. Simultaneous adsorption and degradation process (A+P) had synergetic effect on antibiotic degradation rate. The applicability of power law model indicates the intricacies of mineralization process. During A+P process, both OTC and AMP antibiotics were mineralized to CO2, H2O, NO3- and SO42-ions. The noteworthy recycle efficiency and easier recovery of newlineAbstract newlineSchool of Chemistry xv newlinesynthesized photocatalyst was observed for 10 catalytic cycles as compared to bare BiOCl, Bi2O3/BiOCl and WO3/BiOCl. newlineKeywords: BiOCl, BO/BOC, WO3/BiOCl; Antibiotics; Supported photocatalysis; Adsorption; Mineralization; Kinetics. newline