Abstract
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.
Highlights
Nanoparticle production has increased in a notable way due to its widespread number of applications in different sectors—such as electronic and energy storage [1,2,3,4], industrial catalysis [5,6], pharmaceutical and biomedical [3,7,8,9], food [10,11,12], civil and waste re-use [13,14,15,16], and the environment [13,17,18,19,20,21,22,23]
Metallic and metal oxide nanoparticle synthesis has been widely studied, and many articles can be found in the literature [30]
ZnO attracted the interest of focused research due to its extraordinary electronic, optical, mechanical, magnetic and chemical properties, that are significantly different from those of the bulk counterpart: high chemical stability, high electrochemical coupling coefficient, a broad range of radiation absorption, paramagnetic nature and high photostability [31]
Summary
Nanoparticle production has increased in a notable way due to its widespread number of applications in different sectors—such as electronic and energy storage [1,2,3,4], industrial catalysis [5,6], pharmaceutical and biomedical [3,7,8,9], food [10,11,12], civil and waste re-use [13,14,15,16], and the environment [13,17,18,19,20,21,22,23]. ZnO has been produced by various methods, using vapor deposition or chemical precipitation methods [34] The latter method, prepared in its liquid phase, is advantageous for the production of nanoparticle suspensions, which avoids, among other things, the dispersion of its material in the environment. The use of a spinning disk reactor (SDR) for inorganic and metal oxide nanoparticles production has been studied in the last two decades by a small number of research teams, and less than 100 articles on this subject can be found in the literature [37,38,39,40,41,42,43,44]. The adoption of such equipment may allow for the rapid scaling-up of classical batch productions of nanoparticles, achieving the advantages of a continuous production process (waste reduction, larger reproducibility and production rate, reduced manufacturing cost, higher and consistent product quality, etc. [45]), and the production of size and shape controlled nanoparticles from a bottom-up approach
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
