ZnO Nano-Particles Production Intensification by Means of a Spinning Disk Reactor

Abstract

<jats:p>Zinc Oxide is widely used in many industrial sectors, ranging from photocatalysis, rubber, ceramic, medicine, and pigment, to food and cream additive. The global market is estimated to be USD 3600M yearly, with a global production of 10 Mt. In novel applications, size and shape may sensibly increase the efficiency and a new nano-ZnO market is taking the lead (USD 2000M yearly with a capacity of 1 Mt and an expected Compound Annual Growth Rate of 20%/year). The aim of this work was to investigate the possibility of producing zinc oxide nanoparticles by means of a spinning disk reactor (SDR). A lab-scale spinning disk reactor, previously used to produce other nanomaterials such as hydroxyapatite or titania, has been investigated with the aim of producing needle-shaped zinc oxide nanoparticles. At nanoscale and with this shape, the zinc oxide particles exhibit their greatest photoactivity and active area, both increasing the efficiency of photocatalysis and ultraviolet (UV) absorbance. Working at different operating conditions, such as at different disk rotational velocity, inlet distance from the disk center, initial concentration of Zn precursor and base solution, and inlet reagent solution flowrate, in certain conditions, a unimodal size distribution and an average dimension of approximately 56 nm was obtained. The spinning disk reactor permits a continuous production of nanoparticles with a capacity of 57 kg/d, adopting an initial Zn-precursor concentration of 0.5 M and a total inlet flowrate of 1 L/min. Product size appears to be controllable, and a lower average dimension (47 nm), adopting an initial Zn-precursor concentration of 0.02 M and a total inlet flow-rate of 0.1 L/min, can be obtained, scarifying productivity (0.23 kg/d). Ultimately, the spinning disk reactor qualifies as a process-intensified equipment for targeted zinc oxide nanoparticle production in shape in size.</jats:p>

Nanoscale Chemical Imaging of Nanoparticles under Real‐World Wastewater Treatment Conditions

“…Available sources suggest that the production and use of ZnO nanoparticles are increasing, rising from ≈550 000 kg in 2012 [ 51 ] to ≈1 600 000 kg in 2014, [ 39 ] with the estimated current global production in the range of 10 000 000 kg. [ 52 ] Therefore, elevated concentrations of ZnO in wastewaters have been described as inevitable in the near future. [ 53 ] Here, it was shown that a significant fraction of ZnO nanomaterials was rapidly sulfided during their incubation in influent water.…”

Environmental Fate of Metal Nanoparticles in Estuarine Environments

“…Unlike SiO 2 ENMs, however, Ag ENMs have been studied broadly [27]. Among the most threatening ENMs are ZnO NPs, with an annual global production of 10 Mt [47]. About ten percent of this production is released into the environment and 95% of it enters the aquatic system, accumulating in sediments [48].…”

Editorial for the Special Issue on “Process Intensification Techniques for the Production of Nanoparticles”

“…The bottom-up technologies are the most widely adopted in lab-to-pilot scale applications, whereas the top-down ones may present notable advantages for industrial scale productions. However, to achieve reproducible and homogeneous nanoparticles a number of innovative process units have been developed by various researchers, taking advantage of the particular geometry and fluid-dynamic conditions established inside the specific unit [1][2][3][4][5][6][7][8].…”

“…The authors that contributed to this Special Issue well report, by their work, how the process intensification philosophy can be adopted for the production of nanoparticles of great interest in various industrial and civil applications. The production of zinc oxide [3] and starch [6] nanoparticles, by means of a spinning disk reactor represent a remarkable example of intensified production in the nano-size world. The spinning disk reactor represents one of the most promising PI technologies for the heat and mass transfer rate enhancement, obtained through centrifugal fields generated in the thin liquid film on the reactor disk by the rotation action.…”