ABSTRACT
A TiO2/GO/CuFe2O4 heterostructure photocatalyst is fabricated by a simple and low-cost ball-milling pathway for enhancing the photocatalytic degradation of chlorinated pesticides under UV light irradiation. Based on the advantages of graphene oxide, TiO2, and CuFe2O4, the nanocomposite exhibited visible light absorption, magnetic properties, and adsorption capacity. Integrated analyses using XRD, SEM, TEM, and UV-visible techniques demonstrated that the nanocomposite exhibited a well-defined crystalline phase, sizes of 10-15 nm, and evincing a visible light absorption feature with an optical bandgap energy of 2.4 eV. The photocatalytic degradations of 17 different chlorinated pesticides (persistent organic pollutants) were assayed using the prepared photocatalyst. The photocatalytic activity of the nanocomposite generated almost 96.5% photocatalytic removal efficiency of typical pesticide DDE from water under UV irradiation. The superior photocatalytic performance was exhibited by the TiO2/GO/CuFeO4 catalyst owing to its high adsorption performance and separation efficiency of photo-generated carriers. The photocatalyst was examined in 5 cycles for treating uncolored pesticides with purposeful separation using an external magnetic field.
ABSTRACT
ZnO nanostructures (NS)/guar gum (GG) nanocomposites have been successfully synthesized and tested as sorbents for photodegradation, adsorption and antimicrobial activity for dye removal. The addition of ZnO improves the thermal stability of GG based on the ratio of the oxygen in the OH form and the total oxygen in the samples as indicated via XPS and FTIR analyses. Among all tested composites, the ZnO NPs/GG nanocomposite showed the highest photocatalytic activity and hence used in extended adsorption and degradation studies against the anionic dye reactive red (RR195) and the cationic dye Rhodamine B (RhB). The adsorption mechanism and kinetics were studied in details. The ZnO NPs/GG nanocomposite showed quite high removal efficiency for both dyes reaching about 96 degradation percent of the initial dye concentration as well as a high adsorption capacity reaching 70â¯mgâ¯g-1. The adsorption of both dyes on ZnO NPs/GG was found to obey the Freundlich adsorption model with pseudo-second-order kinetics. The antibacterial assay showed an enhanced antibacterial effect of ZnO/GG against E-Coli/TOP10 (PTA 10989) strain compared to pristine ZnO or pure guar gum. The obtained results were proved to be of high significance based on the statistical analysis using one-way ANOVA followed by Tukey's analysis.
