Correction to "Nanometal Dust Explosion in Confined Vessel: Combustion and Kinetic Analysis".

[This corrects the article DOI: 10.1021/acsomega.1c00967.].

New insight into the kinetic study on the different loadings of the CuO/CNT catalyst and its optimization for p-chloroaniline photodegradation.

The effect of the copper (Cu) content on Cu oxide loaded onto a carbon nanotube (CuO/CNT) catalyst on the mechanistic, kinetic, and photonic efficiency of the photodegradation of p-chloroaniline (PCA) under visible (Vis) and ultraviolet (UV) light irradiation has been explored. For low-loading (1-5 wt%) CuO/CNTs, photodegradation performed better under UV (>84%) rather than the Vis system; this may be due to the presence of abundant defect sites on both CuO and CNTs, which allowed the multielectron reduction of oxygen at their impurity levels to generate more hydrogen peroxide and subsequent ·OH radicals. The active species under UV were in the following order: h+ ≫ e- > ·OH, while it was vice versa for the Vis system with a well-balanced 50 wt% CuO/CNT catalyst that exhibited a similar performance. The kinetic study showed the transition of the kinetic order from the zeroth to the first order on increasing the PCA concentration under the Vis system and vice versa for the UV system. The Thiele modulus (ϕ) further confirmed that the effect of internal mass transfer was negligible under UV light. In contrast, the transition from mass transfer to kinetic control limitation was observed under the Vis system. The optimum PCA degradation predicted from the response surface analysis was 97.36% at the reaction pH of 7.3, catalyst dosage of 0.45 g L-1, and initial PCA concentration of 11.02 mg L-1. The condition obtained was fairly close to the forecasted value with an error of 0.26%.

Interaction Insight of Pullulan-Mediated Gamma-Irradiated Silver Nanoparticle Synthesis and Its Antibacterial Activity.

The production of pure silver nanoparticles (Ag-NPs) with unique properties remains a challenge even today. In the present study, the synthesis of silver nanoparticles (Ag-NPs) from natural pullulan (PL) was carried out using a radiation-induced method. It is known that pullulan is regarded as a microbial polysaccharide, which renders it suitable to act as a reducing and stabilizing agent during the production of Ag-NPs. Pullulan-assisted synthesis under gamma irradiation was successfully developed to obtain Ag-NPs, which was characterized by UV-Vis, XRD, TEM, and Zeta potential analysis. Pullulan was used as a stabilizer and template for the growth of silver nanoparticles, while gamma radiation was modified to be selective to reduce silver ions. The formation of Ag-NPs was confirmed using UV-Vis spectra by showing a surface plasmon resonance (SPR) band in the region of 410-420 nm. As observed by TEM images, it can be said that by increasing the radiation dose, the particle size decreases, resulting in a mean diameter of Ag-NPs ranging from 40.97 to 3.98 nm. The XRD analysis confirmed that silver metal structures with a face-centered cubic (FCC) crystal were present, while TEM images showed a spherical shape with smooth edges. XRD also demonstrated that increasing the dose of gamma radiation increases the crystallinity at a high purity of Ag-NPs. As examined by zeta potential, the synthesized Ag-NP/PL was negatively charged with high stability. Ag-NP/PL was then analysed for antimicrobial activity against Staphylococcus aureus, and it was found that it had high antibacterial activity. It is found that the adoption of radiation doses results in a stable and green reduction process for silver nanoparticles.

The Effect of Precursor Concentration on the Particle Size, Crystal Size, and Optical Energy Gap of CexSn1-xO2 Nanofabrication.

In the present work, a thermal treatment technique is applied for the synthesis of CexSn1-xO2 nanoparticles. Using this method has developed understanding of how lower and higher precursor values affect the morphology, structure, and optical properties of CexSn1-xO2 nanoparticles. CexSn1-xO2 nanoparticle synthesis involves a reaction between cerium and tin sources, namely, cerium nitrate hexahydrate and tin (II) chloride dihydrate, respectively, and the capping agent, polyvinylpyrrolidone (PVP). The findings indicate that lower x values yield smaller particle size with a higher energy band gap, while higher x values yield a larger particle size with a smaller energy band gap. Thus, products with lower x values may be suitable for antibacterial activity applications as smaller particles can diffuse through the cell wall faster, while products with higher x values may be suitable for solar cell energy applications as more electrons can be generated at larger particle sizes. The synthesized samples were profiled via a number of methods, such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR). As revealed by the XRD pattern analysis, the CexSn1-xO2 nanoparticles formed after calcination reflect the cubic fluorite structure and cassiterite-type tetragonal structure of CexSn1-xO2 nanoparticles. Meanwhile, using FT-IR analysis, Ce-O and Sn-O were confirmed as the primary bonds of ready CexSn1-xO2 nanoparticle samples, whilst TEM analysis highlighted that the average particle size was in the range 6-21 nm as the precursor concentration (Ce(NO3)3·6H2O) increased from 0.00 to 1.00. Moreover, the diffuse UV-visible reflectance spectra used to determine the optical band gap based on the Kubelka-Munk equation showed that an increase in x value has caused a decrease in the energy band gap and vice versa.

Nanometal Dust Explosion in Confined Vessel: Combustion and Kinetic Analysis.

Extensive application of metal powder, particularly in nanosize could potentially lead to catastrophic dust explosion, due to their pyrophoric behavior, ignition sensitivity, and explosivity. To assess the appropriate measures preventing accidental metal dust explosions, it is vital to understand the physicochemical properties of the metal dust and their kinetic mechanism. In this work, explosion severity of aluminum and silver powder, which can be encountered in a passivated emitter and rear contact (PERC) solar cell, was explored in a 0.0012 m3 cylindrical vessel, by varying the particle size and powder concentration. The P max and dP/dt max values of metal powder were demonstrated to increase with decreasing particle size. Additionally, it was found that the explosion severity of silver powder was lower than that of aluminum powder due to the more apparent agglomeration effect of silver particles. The reduction on the specific surface area attributed to the particles' agglomeration affects the oxidation reaction of the metal powder, as illustrated in the thermogravimetric (TG) curves. A sluggish oxidation reaction was demonstrated in the TG curve of silver powder, which is contradicted with aluminum powder. From the X-ray photoelectron spectroscopy (XPS) analysis, it is inferred that silver powder exhibited two reactions in which the dominant reaction produced Ag and the other reaction formed Ag2O. Meanwhile, for aluminum powder, explosion products only comprise Al2O3.