The photocatalytic performance of the multilayered NiFe LDH/Activated Carbon was evaluated for the degradation of methylene blue (MB) in industrial textile wastewater, considering prior adsorption on the photocatalyst surface. The XRD, XPS, BET, TEM and FE-SEM results confirmed that the highly exposed mesoporous layers, carbon backbone, and interlayer anions serve as active sites responsible for the adsorption of MB dye due to the expected electrostatic interactions. Electrochemical methods such as CV, LSV and EIS revealed the improved conductivity and supported the interactions observed. Encouraged by these interactions, the irradiation of visible light enabled the degradation of methylene blue, and the degradation products were monitored using UPLC chromatograms and MS spectra. The removal efficiencies of the MB dye were found to be 17.5 %, 51.2 %, 67.1 %, 84.8 %, and 94.2 % due to photolysis, adsorption, and degradation on AC, NiFe LDH nanosheets, and NiFe LDH/AC nanocomposite, respectively. The results of the UPLC chromatograms and MS spectra suggested that MB was mineralized into simpler fragments after 30 min of visible light irradiation. Scavenging studies were examined using a series of scavenging agents. However, the maximum photodegradation was attained in the absence of the scavengers. The reusability studies showed that the MB photodegradation efficiency declined by 20.8 %, possibly due to the loss of the catalyst during the washing step. Nonetheless, the NiFe LDH/AC structure remained intact, suggesting the strong stability of the photocatalyst. The plausible degradation mechanism and probable degradation pathway of MB were outlined and supported by the chromatographs and MS results. The overall results suggest that photocatalysis of cationic dyes such as MB on NiFe LDH/AC should be encouraged to work towards sustainable solutions for textile water treatment.

中文翻译：

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轮胎灰衍生活性炭负载的 NiFe LDH 对纺织工业废水亚甲基蓝染料的协同吸附-光催化修复


考虑到光催化剂表面的先前吸附，评估了多层 NiFe LDH/活性炭在工业纺织废水中降解亚甲蓝 （MB） 的光催化性能。XRD、XPS、BET、TEM 和 FE-SEM 结果证实，由于预期的静电相互作用，高度暴露的介孔层、碳主链和层间阴离子是负责 MB 染料吸附的活性位点。CV、LSV 和 EIS 等电化学方法揭示了电导率的提高，并支持观察到的相互作用。在这些相互作用的鼓励下，可见光照射使亚甲蓝能够降解，并使用 UPLC 色谱图和 MS 谱图监测降解产物。由于 AC、NiFe LDH 纳米片和 NiFe LDH/AC 纳米复合材料的光解、吸附和降解，MB 染料的去除效率分别为 17.5 %、51.2 %、67.1 %、84.8 % 和 94.2 %。UPLC 色谱图和 MS 谱图结果表明，可见光照射 30 min 后，MB 矿化成更简单的碎片。使用一系列清除剂检查清除研究。然而，在没有清道夫的情况下，光降解达到最大。可重复使用性研究表明，MB 光降解效率下降了 20.8%，这可能是由于洗涤步骤中催化剂的损失。尽管如此，NiFe LDH/AC 结构仍然完整，表明光催化剂具有很强的稳定性。概述了 MB 的合理降解机制和可能的降解途径，并得到了色谱仪和 MS 结果的支持。 总体结果表明，应鼓励阳离子染料（如 NiFe LDH/AC 上的 MB）的光催化，以努力寻找纺织水处理的可持续解决方案。