Zn/Cr水滑石吸附-可见光催化水中有机污染物

通过共沉淀法合成可循环使用的阴离子粘土材料锌铬水滑石(Zn/Cr LDHs),并借助X射线衍射(XRD),N2吸附-脱附曲线,扫描电子显微镜(SEM)和紫外-可见光漫反射光谱(DRS)等对其进行表征分析。以刚果红为模型污染物,研究了Zn/Cr LDHs去除有机污染物的吸附-可见光光催化活性。通过等温吸附试验,得到Langmuir等温线,其饱和吸附量为426.29 mg/g。Zn/Cr LDHs在氙灯模拟太阳光照射下,每次试验180 min,第5次后脱色率仍高达96.35%,具有良好的可循环使用性。刚果红吸附等温线符合Langmuir模型,吸附过程符合拟二级动力学模型,内扩散为主要控速步骤,吸附过程是自发的放热过程,低温有利于吸附的进行。

Adsorption-visible light photocatalytic degradation of organic pollutants by Zn/Cr layered double hydroxides

Reusable Zn/Cr layered double hydroxides(ZN / Cr LDHs) were synthesized by a coprecipitation method and characterized by powder X-ray diffraction(XRD),N2adsorption-desorption isotherms,scanning electronic microscopy(SEM) and UV-vis diffuse reflectance spectra(DRS).The adsorption- visible light photocatalytic activity of ZN/Cr LDHs towards organic pollutants was studied with congo red(CR) as the goal pollutant.The results of isothermal adsorption test showed that,the adsorption of CR by ZN/Cr LDHs followed the langmuir isotherm model,and the saturated adsorption capacity was approximately 426.29 mg/L.With the ZN/Cr LDHs that had been used for 5 times,the decolorization rate of wastewater was still about 96.35% after a 180-min irradiation under xenon lamp used as simulated solar light,which indicated that ZN/Cr LDHs had excellent reusability.The adsorption isotherm of CR followed Langmuir model,the adsorption process fitted pseudo-second-order kinetic equation,and the intraparticle diffusion was the rate-controlling step.Lower temperature was favorable to adsorption due to the spontaneous and exothermic nature of adsorption process.