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Biotemplated Synthesis of Hierarchically Porous ZnAl-CLDH/FeWO4 for Effective Removal of Dyes From Water

Liu, Yong, Wang, Gui, Yang, Wenning, Yang, Jie, Li, Jia
Water, air, and soil pollution 2019 v.230 no.4 pp. 89
X-ray diffraction, active sites, adsorption, energy, energy-dispersive X-ray analysis, hydroxides, kinetics, magnetic fields, microparticles, models, nanoparticles, nanosheets, photocatalysis, scanning electron microscopy, sorption isotherms, thermogravimetry, transmission electron microscopy, wastewater treatment
Biotemplating method is a promising way to obtain hierarchical materials with unique morphology and property. In the current work, a novel hierarchically porous ZnAl-CLDH (calcined layered double hydroxides)/FeWO₄ had been successfully synthesized by a facile biotemplated method. The obtained samples were characterized in detail via FESEM-EDX, TEM, XRD, IR, TGA, and BET techniques. The as-synthesized ZnAl-CLDH/FeWO₄ hierarchical microspheres were composed of ZnAl-CLDH nanosheets and FeWO₄ nanoparticles. The obtained sample exhibited both high adsorption and visible-light photocatalytic activity toward Congo Red (CR) in water. It was found that the adsorption process was well described by the pseudo-second-order kinetic model and the Langmuir isotherm model, while the photocatalytic degradation process was well fitted to the first-order kinetics model. The enhanced photocatalytic performance was mainly due to the hierarchically porous structure that could offer more exposed active sites, as well as the unique energy band structure of heterostructures, that facilitated the efficient separation and transfer of photoinduced carriers and enhanced light harvesting. In addition, the as-prepared sample had quickly magnetic response and could be easily separated from water under an external magnetic field after wastewater treatment.