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Rare-earth cerium (Ce)-doped zinc oxide (ZnO) spherical nanoparticles were synthesized by using the co-precipitation method. The doped materials were characterized by means of the X-ray diffraction, Williamson-Hall Plot, and field emission scanning electron microscopy analyses. The prepared nanoparticles exhibit a hexagonal wurtzite structure as observed from the XRD measurements. Energy dispersive X-ray spectroscopy data confirmed the purity of the prepared samples. The photocatalytic activity of the rare-earth Ce-doped ZnO spherical nanoparticles was investigated through the degradation of methylene blue (MB) and p-nitrophenol (PNP) solution under UV light radiation. Among the different amounts of dopant, 5 mole% Ce-doped ZnO nanoparticles showed the highest degradation with UV light radiation for both MB dye and PNP solution. The particle size, morphology, and separation of the photo-induced electron–hole pair are the main factors that influence photocatalytic activity. The probable mechanisms of photocatalytic degradation and mineralization of MB and PNP are also explained by liquid chromatography–mass spectrometry analysis.

The present work deals with the production of nanocapsules containing a natural corrosion inhibition component. Azadirachta indica was encapsulated in urea-formaldehyde polymeric shell using ultrasound-assisted and conventional approaches of in situ polymerization. Subsequently nanocapsules were incorporated into clear epoxy polyamide to develop the green self-healing corrosion inhibition coating. The actual performance of the coating was evaluated based on the studies involving the repair of the crack of high solid surface coating. Corrosion inhibition of the healed area has been evaluated using the electrochemical impedance spectroscopy and immersion test based on the use of standard epoxy coating. The obtained results confirmed better corrosion protection in terms of the electrochemical impendence spectroscopy data and Tafel plot. It was found that current density decreases from 0.0011 A/cm2 (for standard epoxy coating) to 5.22 E−7 A/cm2 as 4 wt% nanocapsules incorporated in coating.

In the present work, synthesis of iron oxide nanoparticles (NPs) using continuous flow microreactor (MR) and advanced flow™ reactor (AFR™) has been investigated with evaluation of the efficacy of the two types of MRs. Effect of the different operating parameters on the characteristics of the obtained NPs has also been investigated. The synthesis of iron oxide NPs was based on the co-precipitation and reduction reactions using iron (III) nitrate precursor and sodium hydroxide as reducing agents. The iron oxide NPs were characterized using transmission electron microscopy (TEM), Fourier transform infrared spectroscopy, and X-ray diffraction (XRD) analysis. The mean particle size of the obtained NPs was less than 10 nm at all flow rates (over the range of 20−60 ml/h) in the case of spiral MR, while, in the case of AFR™, the particle size of NPs was below 20 nm with no specific trend observed with the operating flow rates. The XRD and TEM analyses of iron oxide NPs confirmed the crystalline nature and nanometer size range, respectively. Further, magnetic properties of the synthesized iron oxide NPs were studied using electron spin resonance spectroscopy; the resonance absorption peak shows the g-factor values as 2.055 and 2.034 corresponding to the magnetic fields of 319.28 and 322.59 mT for MR and AFR™, respectively.

The present paper reports the experimental details for the synthesis of performic acid (PFA) using Corning advanced-flow reactors (AFRs) using formic acid and H2O2 as reactants, and sulfuric acid as homogeneous catalyst. The effect of different operating parameters on PFA concentration such as reactant flow rates (residence time), temperature, reactant and catalyst concentration were studied. The experimental results indicate that the heart-shaped pellet structure in AFR provides better mixing, and hence more conversion with less residence time achieved. Moreover, AFR technology offers the possibility to conduct chemical reactions in a more sustainable way due to miniaturization and increased safety. Reactions show optimum results at 30°C with a feed flow rate of 80 ml/h in the presence of 1 w/w % H2SO4 as catalyst. The optimized results demonstrated the capability of AFR technology for enhancement in the formation of PFA (time equal to 1 min) with high conversion (95.85%). Further, it has been found that the concentration of PFA was reached at maximum value within 1 min of time. Therefore, the production of PFA is very fast in a microreactor, which saves our time and energy and in turn it saves the environment on fuel requirement and therefore this process is green.

The present work deals with the use of ultrasound atomization for the preparation of zinc oxide nanostructures. The focus of the work is to understand the effect of different operating parameters, such as ultrasonic power dissipation, flow rate, concentration, and surface tension, on the final particle morphology obtained during the synthesis. The prepared nanostructures were observed under scanning electron microscope to understand the morphology of the synthesized nanostructures. It was established that the final characteristics of the nanostructures, in terms of shape and size, can be effectively controlled by controlling flow rate, precursor concentration, surface tension, and ultrasonic power dissipation. The droplet size was found to increase with an increase in the flow rate of an aqueous solution of zinc nitrate, ultrasonic power, and decrease in the loading of surfactant (polyvinylpyrrolidone). The present work has clearly established the utility of ultrasound-assisted synthesis of nanoparticles with clear evidence for obtaining desired characteristics based on controlled application.

This report is focused on understanding the mixing performance of Newtonian and non‐Newtonian fluids in an SMX static mixer through computational fluid dynamics (CFD) study in Simcenter STAR‐CCM+. For this, the standard SMX mixer with four mixer elements of radius 26 mm was chosen. The aspect ratio (L/D) was taken as 1. The model constructed was compared using pressure drop ratio values available in literature. First, the design was validated for Newtonian fluid, then for shear‐thinning fluid (non‐Newtonian). Mixing patterns produced through particle tracking approach revealed how blending improved as the fluid moved downstream and interacted with increasing number of mixer elements. A sensitivity study was undertaken to investigate the effect of particle injection mechanism on the mixing process. Two injection methods, vertical and horizontal, were explored to check the influence of injection position on mixing. The results indicate that for the given configuration irrespective of the injection location, at least four mixing elements are needed to achieve good mixing for both Newtonian and shear‐thinning fluids investigated in this study. Statistical reports were used to quantify mixing to understand the mixing behaviour for Newtonian and non‐Newtonian fluids with change in Reynolds number. At high Reynolds number, non‐Newtonian fluids exhibited better mixing abilities. Further, efforts were taken to optimize the various design parameters to produce the most optimum solution with a single mixer element for Newtonian fluid. [ABSTRACT FROM AUTHOR]