Photocatalytic degradation of model pharmaceutical pollutant by novel magnetic TiO_2@ZnFe_2O_4/Pd nanocomposite with enhanced photocatalytic activity and stability under solar light irradiation

摘要

In the last decades, the use of magnetic nanocomposites as a catalyst was considered for removal of organic pollutants due to its easy separation. Therefore, initially, TiO_2@ZnFe_2O_4/Pd nanocomposite was prepared and then used in the photodegradation of diclofenac under direct solar irradiation in the batch and continuous systems. The structure, morphology and other specifications of produced nanocatalyst were determined via XRD, VSM, FESEM/EDX, FTIR, GTA, UV-Vis, Zeta potential, XPS and ICP-OES. The effective factors on diclofenac removal via nanophotocatalyst viz. pH, catalyst concentration, initial concentration of diclofenac, and flow rate and column length on diclofenac photodegradation were studied. Based on the results, the optimal rate for pH, catalyst concentration, and initial concentration of diclofenac was 4, 0.03 g/l and 10 mg/l respectively. Pd-coated TiO_2@ZnFe_2O_4 magnetic photocatalyst had higher photocatalytic activity in diclofenac photodegradation in relation to ZnFe_2O_4 and TiO_2@ZnFe_2O_4 under solar light irradiation. The findings showed that after five recycles, the photocatalytic efficiency did not show much reduction i.e. the removal efficiency from 86.1% in the first cycle reduced only to 71.38% in the last cycle. Likewise, in this study, with flow rate reduction and column length increase diclofenac degradation rate increased.