Rapid, continuous, large-scale synthesis of ZnO/Ag hybrid nanoparticles via one-step impinging stream route for efficient photocatalytic and anti-algal applications

Abstract

Although there are many studies on ZnO/Ag nanoparticles, it is still a challenge to achieve rapid, economic, and large-scale preparation of ZnO/Ag nanoparticles with excellent photocatalytic and anti-algal properties, especially maintaining high Ag reduction rate in the industrial production process. In this paper, based on a self-designed impinging stream microreactor, ZnO/Ag hybrid nanoparticles were synthesized by one-step impinging stream route, and NaBH4 reductant with excellent reducing property for Ag was elected. The relative speed between the raw materials is very fast, the turbulent kinetic energy is large, and the shear force in the impact zone is strong, so the product nucleates quickly in a short time, and the ZnO/Ag nanoparticles have uniform particle size. Methyl orange (MO), methyl blue (MB) and rhodamine B (RhB) could be completely degraded over ZnO/Ag hybrid nanoparticles with Ag content of 2.5% in raw materials under UV irradiation for 15 min, 18 min and 12 min, respectively. Furthermore, the photocatalytic efficiency of MO reached 99.3% even after four cycles, demonstrating the excellent stability of ZnO/Ag hybrid nanoparticles. The growth of Skeletonema costatum was inhibited entirely when Ag content was 7.5% in raw materials. This work not only provides an effective strategy for rapid, continuous and economical producing ZnO/Ag nanoparticles, but also offers a valuable clue for large-scale production of the containing Ag nanomaterials with high reduction rate of Ag.