Abstract
Traditional advanced oxidation processes (AOPs) for the removal of toxic and refractory ethylenethiourea (ETU) is uneconomical because of the demand for continuous chemical input and full-scale systems. Herein, ETU was efficiently mineralized without sacrificial reagents for the first time through the utilization of ZnO nano-photocatalysts which were synthesized by the adjustment of ratio between the precursor ZnCl2 and alkaline source KOH during hydrothermal process. Compared to other ZnO samples, ZnO-1/3 (1:3 molar (M) ratio of ZnCl2 to KOH) exhibited higher apparent rate constant (0.00661 min−1) towards the degradation of ETU because of more effective electron-hole separation. The optimum conditions for ETU degradation (ZnO-1/3 dosage of 0.4 g/L, initial ETU concentration of 10 mg/L and photocatalytic reaction temperature of 35 °C) were acquired according to the outcome of the response surface methodology (RSM) based on the Box-Behnken design (BBD), and the predicted maximum removal efficiency of ETU reached 93.17 % and was consistent with the experimental results under this optimum conditions. The h+ and •OH were proved to the main reactive species during the photocatalytic process by the free radical capture experiments and electron spin resonance (ESR) analysis. Furthermore, the possible degradation pathways of ETU were suggested based on the identified degradation intermediates, and the reduced toxicity of intermediates was also demonstrated through the quantitative structure–activity relationship (QSAR) prediction and the growth of mung bean seedlings. Hence, photocatalysis with ZnO can be regarded as a promising alternative for ETU elimination.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: 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.