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Nowadays, the water ecosystem is being polluted due to the rapid industrialization and massive use of antibiotics, fertilizers, cosmetics, paints, and other chemicals. Chemical oxidation is one of the most applied processes to degrade contaminants in water. However, chemicals are often unable to completely mineralize the pollutants. Enhanced pollutant degradation can be achieved by Fenton reaction and related processes. As a consequence, Fenton reactions have received great attention in the treatment of domestic and industrial wastewater effluents. Currently, homogeneous and heterogeneous Fenton processes are being investigated intensively and optimized for applications, either alone or in a combination of other processes. This review presents fundamental chemistry involved in various kinds of homogeneous Fenton reactions, which include classical Fenton, electro-Fenton, photo-Fenton, electro-Fenton, sono-electro-Fenton, and solar photoelectron-Fenton. In the homogeneous Fenton reaction process, the molar ratio of iron(II) and hydrogen peroxide, and the pH usually determine the effectiveness of removing target pollutants and subsequently their mineralization, monitored by a decrease in levels of total organic carbon or chemical oxygen demand. We present catalysts used in heterogeneous Fenton or Fenton-like reactions, such as H 2 O 2-Fe 3+ (solid)/nano-zero-valent iron/immobilized iron and electro-Fenton-pyrite. Surface properties of heterogeneous catalysts generally control the efficiency to degrade pollutants. Examples of Fenton reactions are demonstrated to degrade and mineralize a wide range of water pollutants in real industrial wastewaters, such as dyes and phenols. Removal of various antibiotics by homogeneous and heterogeneous Fenton reactions is exemplified.

Selenium nanoparticles (SeNPs) have revolutionized biomedical domain and are still developing rapidly. Hence, this perspective elaborates SeNPs properties, synthesis, and biomedical applications, together with their potential for management of SARS-CoV-2.

Bioinspired metallic nanoparticles (BMN) have revolutionized the biomedical domain and are still developing rapidly. Hence, this review on BMN elaborates the properties, biosynthesis, biomedical applications, and its role in combating the SARS-CoV-2.

New magnetic iron oxide (Fe3O4)/activated charcoal (AC)/β-cyclodextrin (CD)/sodium alginate (Alg) polymer nanocomposite materials were prepared by direct mixing of the polymer matrix with the nanofillers. The obtained materials were utilized as nano-adsorbents for the elimination of methylene blue (MB), a hazardous water-soluble cationic dye, from aqueous solutions, and showed excellent regeneration capacity. The formation of the nanocomposites was followed by high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectrometry (EDX), Fourier-transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM), X-ray diffraction (XRD) and adsorption of N2 at −196 °C. The rate of adsorption was investigated varying several factors, namely contact time, pH, amount of adsorbent and MB concentration on the adsorption process. Studies dealing with equilibrium and kinetics were carried out in batch conditions. The obtained results indicated that the removal rate of MB was 99.53% in 90 min. Langmuir’s isotherm fitted better to the equilibrium data of MB. Fe3O4/AC/CD/Alg polymer beads shows amazing adsorption capacities in the elimination of cationic dyes (2.079 mg/g for polymer gel beads and 10.63 mg g−1 for dry powder beads), in comparison to other adsorbent materials. The obtained adsorbent is spherical with hydrophobic cross-linked surface properties that enable an easy recovery without any significant weight loss of in the adsorbent used.

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Graphene is a two-dimensional material with sp2 hybridization that has found its broad-spectrum potentialities in various domains like electronics, robotics, aeronautics, etc.; it has recently gained its utilities in the biomedical domain. The unique properties of graphene and its derivatives of graphene have helped them find their utilities in the biomedical domain. Additionally, the sudden outbreak of SARS-CoV-2 has immensely expanded the research field, which has also benefitted graphene and its derivatives. Currently, the world is facing a global pandemic due to the sudden outbreak of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), also known as COVID-19, from its major onset Wuhan city, China, in December 2019. Presently, many new variants and mutants appear, which is more harmful than previous strains. However, researchers and scientists are focused on understanding the target structure of coronavirus, mechanism, causes and transmission mode, treatment, and alternatives to cure these diseases in this critical pandemic situation; many findings are achieved, but much more is unknown and pending to be explored. This review paper is dedicated to exploring the utilities of graphene and its derivatives in combating the SARS-CoV-2 by highlighting their mechanism and applications in the production of biosensors, personal protection equipment (PPE) kits, 3-D printing, and antiviral coatings. Further, the paper also covers the cytotoxicity caused by graphene and its derivatives and highlights the graphene-based derivatives market aspects in biomedical domains. Thus, graphene and graphene-derived materials are our new hope in this pandemic time, and this review helps acquire broad knowledge about them.

Kinetics of Ruthenium(III) [Ru(III)] chloride catalyzed oxidation of valine (Val) has been studied by N-bromophthalimide (NBP) in the acidic medium at 35°C. The reaction rate follows first-order and zero-order dependence with respect to [NBP] and [Val]. First-order kinetics was observed for Ru(III) chloride at low range of concentrations and tending towards zero-order at higher concentrations. A negative effect was observed for [H ? ] and [phthalimide], while a positive effect was observed for [Cl -] on the reaction rate. Hg(OAc) 2 , ionic strength (I), and dielectric constant (D) of the medium did not change significantly the reaction rate. The rate constants as a function of temperature (298-318 K) were used to calculate activation parameters of the oxidation of Val by NBP. A plausible mechanism was proposed to explain the results of kinetic studies, reaction stoichiometry and product analysis.