Abstract
The aim of the present study is to investigate the activity of semiconductor materials on the degradation of pesticides cypermethrin under UV-light (6 W, ? = 354 nm). Three types of photocatalysts were prepared namely Zn/ZnO, Zn/ZnO/TiO2 and Al/Al2O3/TiO2. Zn/ZnO film was prepared by anodic oxidation of zinc in NaOH with various concentrations (0.2, 0.3, 0.4, and 0.5 M) at 12 V for 20 minutes. The best concentration for NaOH is 0.5 M and the best applied voltage in the preparation of Zn/ZnO is 12 V. The Al/Al2O3 film was prepared by anodizing aluminium plate in H2SO4 at 12 V for 60 minutes. TiO2 films were electrodeposited onto Zn/ZnO and Al/Al2O3 by electrolysis technique in (NH4)2[TiO(C2O4)] solution at 12 V for 20 minutes. Zn/ZnO/TiO2/UV shows the highest photocatalytic degradation of cypermethrin compared to the other photocatalytic system. The effects of some operational parameters such as pH and oxidizing agent (H2O2) on the degradation efficiency of the semiconductor were also studied. The optimum pH for the photodegradation of cypermethrin using Zn/ZnO is pH 5. In the presence of H2O2 as the oxidizing agent, the overall reaction is significantly reduced due the scavenging effect of H2O2. The surface morphology of the catalyst was studied by FESEM analysis.
Highlights
Experimental2.1 Anodic deposition of ZnO thin film on zinc sheet
TiO2 is the most commonly used photocatalyst, ZnO is found to be a suitable alternative to TiO2 since ZnO has the same band gap energy and similar photodegradation mechanism as TiO2 (Equation 1 – 5) [Yamaguchi et al., 1(9O927-)].andTihOy2draonxaytal sreadbiacnalds gap energy is 3.2 eV while ZnO band gap energy is 3.17 (OH) generated (Equation 2-3) in the aqueous medium are eV
The photocatalytic activity of the prepared Zn/ZnO, Zn/ZnO/TiO2 and Al/Al2O3/TiO2 catalysts were determined by the photodegradation of cypermethrin
Summary
2.1 Anodic deposition of ZnO thin film on zinc sheet. The zinc plate was set as the anode while a graphite plate was set as the cathode and both plates were placed at a distance of 50 mm for one another in NaOH aqueous solution (0.2, 0.3, 0.4, 0.5 M). The plate obtained was referred as Zn/ZnO. The alumite plate obtained was referred as Al/Al2O3. 2.2 The preparation of TiO2 thin film on zinc oxide substrate by electrodeposition process. The plate obtained was referred as Zn/ZnO/TiO2 (Z05T). The plate obtained was referred as Al/Al2O3 /TiO2 (A3T). The photocatalytic activity of the prepared Zn/ZnO, Zn/ZnO/TiO2 and Al/Al2O3/TiO2 catalysts were determined by the photodegradation of cypermethrin. For the first 90 minutes, the sample was allowed to be adsorbing on the surface of the catalyst support.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
