Microfluidic synthesis of ZnWO₄ nanoparticles and its performance in DMSO-containing wastewater treatment

A systematic comparison between batch and continuous microfluidics systems was conducted for the synthesis of ZnWO₄ nanoparticles. A series of ZnWO₄ nanoparticles were prepared by different operating modes, initial concentration of reactants and residence time. The features of ZnWO₄ nanoparticles including microscopic morphology, particle size distribution and chemical structure were systematically characterized. The results showed that the continuous microfluidics system could obtain ZnWO₄ nanoparticles with a more uniform particle size compared with batch system. The size of ZnWO₄ are reduced from 92.6 to 65.2 nm by changing the reaction system. Besides, a low concentration of reactants is more suitable for preparing smaller particles ZnWO₄ nanoparticles. The average diameters of prepared ZnWO₄ nanoparticles was reduced to 50 nm in the condition that the residence time was 20 s and the concentration of reactants was 0.1 mol/L. Afterward, the degradation of dimethyl sulfoxide (DMSO) in the wastewaters was used as a probe reaction to evaluate the catalysis performance of prepared ZnWO₄ nanoparticles. This work indicates the potential opportunity of versatile continuous microfluidics technique for the fabrication of various multifunctional metal tungstates nanoparticles.