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Preparation of Highly Dispersed and Small-Sized ZnO Nanoparticles in a Membrane Dispersion Microreactor and Their Photocatalytic Degradation

Huang, Cui, Wang, Yujun, Luo, Guangsheng
Industrial & Engineering Chemistry Research 2013 v.52 no.16 pp. 5683-5690
X-ray diffraction, aqueous solutions, bubbles, carbon dioxide, engineering, methyl orange, mixing, nanoparticles, particle size, photocatalysis, raw materials, transmission electron microscopy, ultraviolet radiation, zinc oxide, zinc sulfate
Highly dispersed ZnO nanoparticles were prepared by membrane dispersion using ZnSO₄ and NH₄HCO₃ aqueous solutions as raw materials. The particle size and aggregation of ZnO were reduced by intensifying the mixing performance and using CO₂ bubbles. The properties of the ZnO nanoparticles were characterized by X-ray diffraction, transmission electron microscopy, and Brunauer–Emmett–Teller analysis. The relationship between the mixing performance of the microreactor and the size and monodispersion of ZnO nanoparticles was investigated. The particle size decreased with the decrease in segregation index Xₛ. Monodispersion appeared to be related to the micromixing performance and the ratio R of dispersed feed flow rate to continuous feed flow rate. ZnO nanoparticles with size of 11 nm and agglomeration coefficient CF of 1.181 were successfully prepared when R = 2.0 and Xₛ = 0.0004. Smaller-sized ZnO nanoparticles showed greater photocatalytic activity toward methyl orange with a degradation of 97.5% under UV light radiation for 90 min.