Novel ZnO/Zn-Cr hydrotalcite-like anionic clay as a high-performance and recyclable material for efficient photocatalytic removal of organic dye under simulated solar irradiation

摘要

Reusable ZnO/Zn-Cr hydrotalcite-like anionic clays (ZnO/Zn-Cr HACs) were synthesized by a co-precipitation method and characterized by powder X-ray diffraction, Fourier transform infrared spectroscopy, N-2 adsorption-desorption analysis, elemental mapping patterns, scanning electronic microscope, and UV-Vis diffuse reflectance spectra. Its adsorption and photocatalytic activity towards organic pollutant (congo red as a model pollutant) were evaluated. The Langmuir isotherm was used to fit the equilibrium experiments. Saturated adsorption capacity of ZnO/Zn-Cr HACs was 426.29 mg g(-1) at 308 K. The model pollutant exhibited fast and highly efficient removal from aqueous solution by ZnO/Zn-Cr HACs under simulated solar light irradiation. The experiments of cycles demonstrated that there was no evident change in the removal efficiency of Congo red (CR) solution by ZnO/Zn-Cr HACs the fifth time under simulated solar light irradiation, which indicates that ZnO/Zn-Cr HACs can be reused and will be favorable for effective elimination of toxic organic compounds in wastewater. Therefore, it is expected that ZnO/Zn-Cr HACs with layered structures and high surface areas can be potentially used as effective and reusable materials for large-scale environmental purification.