Alam Umair, Pandey Komal, Verma Nishith
Department of Chemical Engineering, Indian Institute of Technology Kanpur, Kanpur, 208016, India.
Center for Environmental Science and Engineering, Indian Institute of Technology, Kanpur, 208016, India.
Chemosphere. 2022 Jun;297:134119. doi: 10.1016/j.chemosphere.2022.134119. Epub 2022 Feb 25.
Photocatalytic treatment of wastewater using nanomaterials is an efficient energy saving technology. Yet the practical application of the technology is limited because of difficulty in developing the stable, supported photocatalytic nanoparticles that can be used under continuous flow conditions. Here, we report an efficient removal of glyphosate (GLP) and Cr(VI) from water under batch as well as continuous flow conditions using the activated carbon fiber (ACF)-supported nanocomposite of CoNiWO (CNW) and g-CN (gCN), as a photocatalyst. CNW-gCN/ACF is synthesized using a one-step strategy, and spectroscopic characterization techniques are used to corroborate the formation of the Z-scheme-based CNW-gCN heterojunction in the ACF substrate. Efficacy of the photocatalyst is assessed in visible light irradiation. The batch activity data of the individual pollutant show the complete oxidation of GLP at 30 ppm and reduction of Cr(VI) at 200 ppm concentration levels in 60 and 150 min, respectively at 1 g/L dose of CNW-gCN/ACF. Photocatalytic efficiency of CNW-gCN/ACF in the simultaneous removal of both pollutants from co-contaminated feed is found to be greater than that in single-feed system under identical experimental conditions. Tested under flow conditions, CNW-gCN/ACF shows approximately the same rates of oxidation and reduction as prevalent under batch conditions, indicating the efficient immobilization of the nanocatalyst particles in ACF, which not only prevents elution of the catalyst but also improves its reusability. The toxicity data indicate the treated water samples to be non-toxic. The current study provides an efficient method for developing supported nanomaterial photocatalysts for treating flowing co-contaminated wastewater.
使用纳米材料对废水进行光催化处理是一种高效节能技术。然而，由于难以开发出可在连续流动条件下使用的稳定负载型光催化纳米颗粒，该技术的实际应用受到限制。在此，我们报告了一种使用负载在活性炭纤维（ACF）上的CoNiWO（CNW）和g-CN（gCN）纳米复合材料作为光催化剂，在间歇和连续流动条件下从水中高效去除草甘膦（GLP）和Cr（VI）的方法。采用一步法合成了CNW-gCN/ACF，并使用光谱表征技术来证实ACF基质中基于Z型的CNW-gCN异质结的形成。在可见光照射下评估光催化剂的效能。在1 g/L剂量的CNW-gCN/ACF下，单个污染物的间歇活性数据表明，在60分钟内可将30 ppm的GLP完全氧化，在150分钟内可将200 ppm浓度水平的Cr（VI）还原。发现在相同实验条件下，CNW-gCN/ACF在同时去除共污染进料中两种污染物时的光催化效率高于单进料系统。在流动条件下测试时，CNW-gCN/ACF显示出与间歇条件下大致相同的氧化和还原速率，这表明纳米催化剂颗粒在ACF中有效固定，这不仅防止了催化剂的洗脱，还提高了其可重复使用性。毒性数据表明处理后的水样无毒。当前研究提供了一种开发负载型纳米材料光催化剂以处理流动的共污染废水的有效方法。
