Centrifugal isolation of SARS-CoV-2: numerical simulation for purification of hospitals' air.

Coronavirus and its spread all over the world have been the most challenging crisis in 2020. Hospitals are categorized among the most vulnerable centers due to their presumably highest traffic of this virus. In this study, centrifugal isolation of coronavirus is successfully deployed for purifying hospitals' air using air conditioners and ducts, suggesting an efficient setup. Numerical simulations have been used to testify the proposed setup due to the complexities of using experimental investigation such as high cost and clinical hazards of the airborne SARS-CoV-2 in the air. Results show that a 20-cm pipe with an inlet velocity of 4 m/s constitutes the best choice for the separation and purification of air from the virus. The proposed scalable method also efficiently separates larger particles, but it can separate smaller particles too. Numerical results also suggest installing the air purifying system on the floor of the hospitals' room for maximum efficiency.

A Biotechnological Strategy for Molybdenum Extraction Using Acidithiobacillus ferrooxidans.

Biosorption is a potential tool for the extraction of metals from contaminated water and recovery of precious metals, which is a convenient alternative to conventional processes. In the present study, molybdenum recovery by Acidithiobacillus ferrooxidans strain ZT-94 was evaluated. Additionally, the effects of pH initial concentration of molybdenum, contact time, adsorbent concentration, and temperature on the biosorption were investigated. As revealed by the results, the greatest amount of molybdenum sorption was achieved at pH 5. By increasing the concentration of molybdenum from 2 to 45 mg/l, the molybdenum removal increases from 71.13 to 150 mg/g dry weight of biomass, but biosorption efficiency decreased. Also, increasing the dry weight of biomass from 0.008 to 0.06 g/l degreased the biosorption efficiency from 20.68 to 85.69%. The results of molybdenum biosorption were evaluated by Langmuir and Freundlich adsorption isotherm. The maximum biosorption capacity for molybdenum extraction was 150.497 mg/g and amount which is very suitable for a biosorbent. The biosorption was examined by scanning electron microscopy-energy-dispersive X-ray spectroscopy. Because of the elevated biosorption properties of molybdenum by this biosorbent, it can be concluded that Acidithiobacillus ferrooxidans strain ZT-94 is a promising candidate for the removal and recovery of molybdenum from aqueous systems.