Mohammed Alsawat

The journal retracts the article “Utilizing of (Zinc Oxide Nano-Spray) for Disinfection against “SARS-CoV-2” and Testing Its Biological Effectiveness on Some Biochemical Parameters during (COVID-19 Pandemic)—“ZnO Nanoparticles Have Antiviral Activity against (SARS-CoV-2)” Coatings 2021, 11, 388”

Globally, environmental pollution is an important issue. Various pollutants present in water resources, such as bacteria, heavy-metal ions, and organic pollutants, cause serious problems to the environment, animals, plants, and human health. Among the water resources, pollutants, dyestuff, which is discharged from dyeing, textile, and other industrial processes, is an important class of pollutants. Removing these dye pollutants from water resources and wastewater is vital and important due to their toxicity. In this work, a CrFeO₃-carbon nanotube (CNT) adsorbent was synthesized using environmentally friendly methods. The synthesized CrFeO3-CNT adsorbent was characterized stoichiometrically, spectroscopically, and morphologically. The synthesized CrFeO₃-CNT adsorbent was tested for the removal of two dyes: Methyl violet 2B (MV) and Azocarmine G2 (AC) from an aqueous solution. Crushing CrFeO₃ composite with multi-walled fullerene CNT to prepare CrFeO₃-CNT adsorbent improved the adsorption performance of free multi-walled fullerene CNT towards MV dye by 30% and towards AC dye by 33.3%.

A newly synthesized zinc (II) oxide nanoparticle (ZnO-NPs) has been used as a disinfectant Nano-spray for the emerging corona virus (SARS-CoV-2). The synthesized obtained nanomaterial of (ZnO) was fully chemically characterized by using different spectroscopic analysis (FT-IR, UV and XRD) and surface analysis techniques. ZnO-Nps surface morphology and chemical purity has been investigated by transmission electron microscope (TEM), high resolution transmission electron microscope (HR-TEM), scanning electron microscopy (SEM) as well as energy dispersive X-ray analysis (EDX), Additionally Zeta potential and Zeta size distribution were measured and evaluated to confirm its nano-range scale. The synthesized Zno-NPs have been tested using 10% DMSO and ddH₂O for estimation of antiviral activity against (SARS-CoV-2) by using cytotoxicity assay (CC₅₀) and inhibitory concentration (IC₅₀). The results revealed that (Zno-NPs) has high anti-SARS-CoV-2 activity at cytotoxic concentrations in vitro with non-significant selectivity index (CC₅₀/IC₅₀ ≤ 1). The current study results demonstrated the (ZnO-NPs) has potent antiviral activity at low concentration (IC₅₀ = 526 ng/mL) but with some cytotoxic effect to the cell host by (CC₅₀ = 292.2 ng/mL). We recommend using of (ZnO-NPs) as potent disinfectant against (SARS-Cov-2), but there are slight side effects on the cellular host, so we recommend more prospective studies on complexation of other compounds with (ZnO-NPs) in different concentrations to reduce its cellular toxicity and elevate its antiviral activity against SARS-CoV-2 activities.

Al Amar gold ore is rich in sulfides of base metals and is commercially applied for the production of copper concentrate via floatation and gold bullion by cyanidation of tailing. The current process flowsheet suffers from low gold recovery (∼60%) and loss of metals in the hazardous stockpiled residue. This work addresses these drawbacks by a newly experimental redesign of the process circuit. The innovative flowsheet comprises a sequence of operations, including acid leaching of the roasted ore, gold recovery from the leach residue, and preparation of a valuable zinc–copper–lead ferrite from the filtrate by coprecipitation followed by heat treatment. The ore is roasted at 650 °C and then leached in 20% HCl, where most of Zn, Cu, Pb, and Fe contents are dissolved, while pristine gold remains in the residue. Most of the gold (∼93%) can be recovered by cyanidation of the acid leach residue. Stoichiometric ratios of dissolved Zn, Cu, Pb, and Fe in the acid leach solution can be kept at 0.6:0.3:0.1:2.0, respectively, only by adding a small amount of ferric chloride. These metals are coprecipitated at varying pH values from 8 to 10, and the produced powders are annealed at temperatures from 600 to 1100 °C. X-ray diffraction (XRD) charts reveal sharp peaks of the targeted Zn_0.6Cu_0.3Pb_0.1Fe₂O₄ phase at 600 °C, while a highly crystalline single phase is obtained at 1100 °C, independently of precipitation pH. The crystalline size of the produced powders increases with annealing temperatures (from 18–27 nm at 600 °C to 85–105 nm at 1100 °C). The finest size is found at pH 12. Scanning electron microscopy (SEM) investigation shows uniform cubic microstructures of samples annealed at 1100 °C. The produced ferrite powders exhibit soft magnetic characteristics. Saturation magnetization, M_s, substantially increases with pH. Coercivity, H_c, increases with increasing annealing temperatures, from 600 to 800 °C, and decreases above 800 °C. Preliminary cost–benefit analysis revealed that the profit margin of the proposed process flowsheet is promising. The wastewater is almost free of heavy metals. Our advances in high gold recovery and preparation of valuable magnetic nanocrystalline ferrite provide exciting opportunities to enhance and maximize Al Amar ore production for practical applications.