席夫碱钴改性CoCr-LDHs材料光催化降解亚甲基蓝研究

采用共沉淀法合成席夫碱钴(SBCo)插层钴铬水滑石(CoCr-LDHs)材料。通过X射线粉末衍射(XRD)、紫外-可见漫反射光谱(UV-Vis DRS)、扫描电子显微镜(SEM)、透射电子显微镜(TEM-EDX)、X射线光电子能谱(XPS)、比表面积(BET)分析表征CoCr-LDHs以及CoCr/SBCo-LDHs材料的结构和性质。以H₂O₂作光催化助剂, 考察了不同插层量、催化剂用量以及亚甲基蓝溶液的初始浓度对光催化活性的影响, 并探究了光催化降解过程的动力学和主要的活性基团。实验结果表明: H₂O₂有助于提高水滑石材料的光催化性能, 以氙灯模拟太阳光, 20 mg CoCr/SBCo_0.5-LDHs和H₂O₂的协同作用对初始浓度为25 mg/L的亚甲基蓝降解率高达99%。亚甲基蓝的光降解过程符合准一级动力学模型, 且起主要作用的活性基团为h ⁺和·OH。

Photocatalytic Degradation of Methylene Blue by Schiff-base Cobalt Modified CoCr Layered Double Hydroxides

A series new material of cobalt (Ⅱ) with Schiff-base intercalated cobalt-chromium layered double hydroxides (CoCr/SBCo-LDHs) were successfully prepared via coprecipitation. Their structure and property of the CoCr-LDHs and CoCr/SBCo-LDHs materials were thoroughly characterized by X-ray powder diffraction (XRD), UV-Vis DRS, scanning electron microscope (SEM), transmission electrons microscope (TEM) and energy dispersive X-ray spectroscope (EDX), X-ray photoelectron spectroscope, and specific surface area analyzer. Using H₂O₂ as photocatalytic additive, the effects of different intercalation amount, catalyst dosage and initial concentration of methylene blue (MB) solution on photocatalytic activity were investigated, and the kinetics and main active groups of photocatalytic degradation process were explored. Experimental results show that H₂O₂ can improve the photocatalytic performance of hydrotalcite materials. Under the condition of the Xenon lamp simulated sunlight and MB initial concentration of 25 mg/L, the photocatalytic degradation rate of MB by 20 mg CoCr/SBCo_0.5-LDHs and H₂O₂ was 99%. The photodegradation process of MB conforms to the quasi-first-order kinetic model, and the active groups playing major role are h ⁺ and ·OH.