Insights into the Adsorption Properties of Mixed Matrix Membranes (Pebax 1657-g-Chitosan-PVDF-Bovine Serum Albumin@ZIF-CO3-1) for the Antiviral COVID-19 Treatment Drugs Remdesivir and Nirmatrelvir: An In Silico Study.

The effect of the COVID-19 pandemic on the accumulation of environmental pollutants has been significant. In that way, waste management systems have faced problems, and the amount of hazardous and medical wastes has increased. As pharmaceuticals associated with the treatment of COVID-19 enter the environment, aquatic and terrestrial ecosystems have been negatively impacted, potentially disrupting natural processes and harming aquatic life. This analysis seeks to appraise the potential of mixed matrix membranes (MMMs) composed of Pebax 1657-g-chitosan-polyvinylidene fluoride (PEX-g-CHS-PVDF)-bovine serum albumin (BSA)@ZIF-CO3-1 as adsorbents for removing remdesivir (REMD) and nirmatrelvir (NIRM) from aqueous environments. An in silico study was conducted to explore the adsorption characteristics, physicochemical properties, and structural features of these MMMs, employing quantum mechanical (QM) calculations, molecular dynamics (MD) simulations, and Monte Carlo (MC) simulations as research methodologies. Incorporating BSA@ZIF-CO3-1 into the PEX-g-CHS-PVDF polymer matrix improved the physicochemical properties of MMMs by promoting the compatibility and interfacial adhesion between the two materials, facilitated by electrostatic interactions, van der Waals forces, and hydrogen bonding. Investigation of the interaction mechanism between the title pharmaceutical pollutants and the surfaces of MMMs, along with the description of their adsorption behavior, was also conducted by applying MD and MC approaches. Our observations indicate that the adsorption behavior of REMD and NIRM is influenced by molecular size, shape, and the presence of functional groups. Molecular simulation analysis demonstrated that the MMM membrane is a highly suitable adsorbent for the adsorption of REMD and NIRM drugs, with a higher affinity toward REMD adsorption. Our study emphasizes the significance of computational modeling in developing practical strategies for eliminating COVID-19 drug contaminants from wastewater. The knowledge obtained through our molecular simulations and QM calculations can assist in creating more efficient adsorption materials, resulting in a cleaner and healthier environment.

Chitosan-supported metal nanocatalysts for the reduction of nitroaromatics.

The second most abundant natural polymer in the earth's crust is chitosan (CS). The unique physical, chemical, structural, and mechanical features of this natural polymer have led to its increased application in a variety of fields such as medicine, catalysis, removal of pollutants, etc. To eliminate various pollutants, it is preferable to employ natural compounds as their use aids the removal of contaminants from the environment. Consequently, employing CS to eliminate contaminants is a viable choice. For this aim, CS can be applied as a template and support for metal nanoparticles (MNPs) and prevent the accumulation of MNPs as well as a reducing and stabilizing agent for the synthesis of MNPs. Among the pollutants present in nature, nitro compounds are an important and wide category of biological pollutants. 4-Nitrophenol (4-NP) is one of the nitro pollutants. There are different ways for the removal of 4-NP, but the best and most effective method for this purpose is the application of a metallic catalyst and a reducing agent. In this review, we report the recent developments regarding CS-supported metallic (nano)catalysts for the reduction of nitroaromatics such as nitrophenols, nitroaniline compounds, nitrobenzene, etc. in the presence of reducing agents. The metals investigated in this study include Ag, Au, Ni, Cu, Ru, Pt, Pd, etc.