UV-CDs/沸石-4A/TiO 复合光催化剂的制备及其在紫外光辐照下光催化降解染料的研究。

Study on preparation of UV-CDs/Zeolite-4A/TiO composite photocatalyst coupled with ultraviolet-irradiation and their application of photocatalytic degradation of dyes.

机构信息

College of Mining Engineering, Taiyuan University of Technology, Taiyuan, 030024, Shanxi, China; Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB, T6G 1H9, Canada.

College of Mining Engineering, Taiyuan University of Technology, Taiyuan, 030024, Shanxi, China.

出版信息

J Environ Manage. 2024 Mar;354:120342. doi: 10.1016/j.jenvman.2024.120342. Epub 2024 Feb 20.

DOI:10.1016/j.jenvman.2024.120342

PMID:38382431

Abstract

In this work, ultraviolet irradiation was employed to assist in the preparation of a novel photocatalyst composite in the form of carbon dots/zeolite-4A/TiO, using coal tailings as the source of silicon-aluminum and carbon. The composite was designed for the degradation of methylene blue under 500 W of UV light irradiation. Zeolite-4A was used as a support for the well-dispersed carbon dots and TiO nanoparticles. The as-prepared composites were subjected to thorough characterization, confirming the successful formation of zeolite-4A with a cube structure, along with the loading of TiO and coal-based CDs in the composites. The experimental results demonstrated that the UV-CZTs nanocomposites exhibited a remarkable removal efficiency of 90.63% within 90 min for MB. The corresponding rate constant was exceptionally high at 0.0331 min, surpassing that of the Dark-CZTs and pure TiO. This significant enhancement was possibly due to the synergistic effect of adsorption photocatalysis of the UV-CZTs, combined with the excellent electron-accepting capabilities of the coal-based CDs, which led to highly improved charge separation. An investigation of the spent photocatalyst's recyclability revealed that it retained a remarkable 82.94% MB removal efficiency after five consecutive cycles, signifying the stability of the composite. Trapping experiments also elucidated the primary reactive species responsible for MB degradation, which were identified as photo-generated holes and ⸱O species. By this process, the hydroxyl radicals generated in the system successfully promoted the transformation of coal tailings to coal-based zeolite and coal-based CDs. Coal-based zeolite served as an excellent carrier of titanium dioxide, which improved its dispersibility. The inhibition of e-h recombination of titanium dioxide by introducing coal-based CDs improved the photocatalytic ability of titanium dioxide. Through this study, coal tailings, as a coal processing waste, were transformed into high-value materials, and relevant photocatalytic composite materials could be prepared with broad application prospects.

摘要

在这项工作中，采用紫外线辐射辅助制备了一种新型的碳点/沸石-4A/TiO 光催化剂复合材料，以煤矸石为硅铝和碳的来源。该复合材料设计用于在 500 W 紫外光照射下降解亚甲基蓝。沸石-4A 用作碳点和 TiO 纳米颗粒的良好分散载体。所制备的复合材料经过彻底的表征，证实成功合成了具有立方结构的沸石-4A，以及负载在复合材料中的 TiO 和基于煤的 CDs。实验结果表明，在 90 分钟内，UV-CZTs 纳米复合材料对 MB 的去除效率达到 90.63%。相应的速率常数异常高，达到 0.0331 min，超过了 Dark-CZTs 和纯 TiO 的速率常数。这种显著的增强可能是由于 UV-CZTs 的吸附光催化协同作用，以及基于煤的 CDs 的优异电子接受能力，导致电荷分离得到极大改善。对用过的光催化剂的可回收性的研究表明，它在五个连续循环后仍保持了 82.94%的显著 MB 去除效率，表明了复合材料的稳定性。捕获实验还阐明了导致 MB 降解的主要活性物质，它们被确定为光生空穴和 ⸱O 物质。通过这个过程，系统中产生的羟基自由基成功地促进了煤矸石向基于煤的沸石和基于煤的 CDs 的转化。基于煤的沸石作为二氧化钛的优良载体，提高了其分散性。通过引入基于煤的 CDs 抑制了二氧化钛的电子-空穴复合，提高了二氧化钛的光催化能力。通过这项研究，煤矸石作为一种煤炭加工废物，被转化为高价值材料，并且可以制备出具有广阔应用前景的相关光催化复合材料。