Li Hanliang, Bharti Bandna, Manikandan Velu, AlSalhi Mohamad S, Asemi Nassar N, Wang Yanan, Jin Wenbiao, Ouyang Feng
School of Civil and Environmental Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen, 518055, PR China; Environmental Science and Engineering Department, Liaoning Technical University, Fuxin, 123000, PR China.
Department of Chemistry, DAV University, Jalandhar, Punjab, 144001, India.
Chemosphere. 2023 Nov;340:139986. doi: 10.1016/j.chemosphere.2023.139986. Epub 2023 Aug 26.
In this study, we investigated the deactivation kinetics and mechanism of N-F-TiO/SiO nanopowder as a model photocatalyst for the purpose of facilitating the photocatalytic degradation of acrylonitrile (AN) in aqueous environment. Prior research has already displayed the proficient degradation of AN through the utilization of N-F-TiO/SiO catalysts, revealing a degradation efficiency of 81.2% within a span of 6 min at an initial AN concentration of 10 mg/L. Multiple variables including the initial AN concentration, illumination intensity, and initial pH value were extensively analyzed during the degradation process. The kinetics of photocatalytic degradation of AN, facilitated by the N-F-TiO/SiO photocatalyst, were modeled by fitting the pseudo first-order reaction kinetics to each individual factor. Furthermore, the adverse effect of catalyst poisoning during the photocatalytic breakdown of AN using the N-F-TiO/SiO photocatalyst was analyzed through a range of different techniques including SEM, XPS, BET, XRD, TG, and NH-TPD. The incorporation of findings from these diverse techniques revealed that, the primary factors contributing to the photocatalyst's poisoning were as follows: (i) During the degradation process, the build-up of intermediate molecules on active sites hindered their functionality, leading to a decrease in the efficiency of the photocatalytic reaction, (ii) Carbonaceous deposits formed when the catalyst's pore structure was obstructed by pollutants or intermediate products that had not undergone timely photocatalytic breakdown and (iii) The persistent erosion of active sites due to hydraulic forces resulted in inadequate performance of the N-F-TiO/SiO photocatalyst in aqueous solutions. A comprehensive analysis of the deactivation kinetics was conducted, deciding in the formulation of a detailed poisoning mechanism for the N-F-TiO/SiO photocatalyst. Additionally, we explored the catalysts regeneration, involving thermal treatment, ultrasonic irradiation, and catalyst reloading. This study not only advances our insight into the waning performance of catalysts in aqueous media but also establishes a conceptual framework for extrapolating analogous deactivation dynamics in other catalysts, grounded in precedent experimental knowledge. This research contributes to the development of a deactivation model for catalysts in the aqueous environment, based on existing experimental research, providing a theoretical framework for understanding the deactivation process of photocatalysts.
在本研究中，我们以N-F-TiO/SiO纳米粉末作为模型光催化剂，研究其失活动力学和机理，以促进丙烯腈（AN）在水环境中的光催化降解。先前的研究已经表明，利用N-F-TiO/SiO催化剂可有效降解AN，在初始AN浓度为10mg/L的情况下，6分钟内降解效率达81.2%。在降解过程中，对包括初始AN浓度、光照强度和初始pH值在内的多个变量进行了广泛分析。通过将伪一级反应动力学拟合到各个因素，对由N-F-TiO/SiO光催化剂促进的AN光催化降解动力学进行了建模。此外，通过扫描电子显微镜（SEM）、X射线光电子能谱（XPS）、比表面积分析仪（BET）、X射线衍射仪（XRD）、热重分析仪（TG）和氨程序升温脱附（NH-TPD）等一系列不同技术，分析了使用N-F-TiO/SiO光催化剂光催化分解AN过程中催化剂中毒的不利影响。这些不同技术的研究结果表明，导致光催化剂中毒的主要因素如下：（i）在降解过程中，活性位点上中间分子的积累阻碍了其功能，导致光催化反应效率降低；（ii）当催化剂的孔结构被未及时进行光催化分解的污染物或中间产物阻塞时，形成了碳质沉积物；（iii）由于水力作用导致活性位点持续侵蚀，使得N-F-TiO/SiO光催化剂在水溶液中的性能不足。对失活动力学进行了全面分析，确定了N-F-TiO/SiO光催化剂详细的中毒机理。此外，我们还探索了催化剂的再生方法，包括热处理、超声辐照和催化剂再装填。本研究不仅增进了我们对催化剂在水介质中性能下降的理解，还基于先前的实验知识，建立了一个用于推断其他催化剂类似失活动力学的概念框架，并基于现有实验研究，为水环境中催化剂失活模型的发展做出了贡献，为理解光催化剂的失活过程提供了理论框架。
