Green synthesis is employed to prepare cobalt/cellulose nanocomposites with cubic (α-cobalt) cobalt as a main component with antibacterial and magnetic properties. An in situ reduction of aqueous solutions of cobalt ions on a model cellulose substrate surface using hydrogen gas affords spherical, cellulose-stabilised cobalt nanoclusters with magnetic properties and an average diameter of 7 nm that are distributed evenly over the surface of the cellulose fibres. These cobalt/cellulose nanocomposites exhibit good antibacterial action against opportunistic pathogens both Gram-positive (S. aureus) and Gram-negative (E. coli, A. baumannii and P. aeruginosa), with zones of inhibition up to 15 mm, thereby encouraging the deployment of these advanced materials for the treatment of wastewater or within medical dressings. This method of preparation is compared with the analogous in situ reduction of cobalt ions on a cellulose surface using sodium borohydride as reducing agent.

Water pollution has become a critical issue because of the Industrial Revolution, growing populations, extended droughts, and climate change. Therefore, advanced technologies for wastewater remediation are urgently needed. Water contaminants are generally classified as microorganisms and inorganic/organic pollutants. Inorganic pollutants are toxic and some of them are carcinogenic materials, such as cadmium, arsenic, chromium, cadmium, lead, and mercury. Organic pollutants are contained in various materials, including organic dyes, pesticides, personal care products, detergents, and industrial organic wastes. Nanostructured materials could be potential candidates for photocatalytic reduction and for photodegradation of organic pollutants in wastewater since they have unique physical, chemical, and optical properties. Enhanced photocatalytic performance of nanostructured semiconductors can be achieved using numerous techniques; nanostructured semiconductors can be doped with different species, transition metals, noble metals or nonmetals, or a luminescence agent. Furthermore, another technique to enhance the photocatalytic performance of nanostructured semiconductors is doping with materials that have a narrow band gap. Nanostructure modification, surface engineering, and heterojunction/homojunction production all take significant time and effort. In this review, I report on the synthesis and characterization of nanostructured materials, and we discuss the photocatalytic performance of these nanostructured materials in reducing environmental pollutants.

The electrochemical sensing of biomarkers has attracted more and more attention due to the advantages of electrochemical biosensors, including their ease of use, excellent accuracy, and small analyte volumes. Thus, the electrochemical sensing of biomarkers has a potential application in early disease diagnosis diagnosis. Dopamine neurotransmitters have a vital role in the transmission of nerve impulses. Here, the fabrication of a polypyrrole/molybdenum dioxide nanoparticle (MoO₃ NP)-modified ITO electrode based on a hydrothermal technique followed by electrochemical polymerization is reported. Several techniques were used to investigate the developed electrode’s structure, morphology, and physical characteristics, including SEM, FTIR, EDX, N₂ adsorption, and Raman spectroscopy. The results imply the formation of tiny MoO₃ NPs with an average diameter of 29.01 nm. The developed electrode was used to determine low concentrations of dopamine neurotransmitters based on cyclic voltammetry and square wave voltammetry techniques. Furthermore, the developed electrode was used for monitoring dopamine in a human serum sample. The LOD for detecting dopamine by using MoO₃ NPs/ITO electrodes based on the SWV technique was around 2.2 nmol L⁻¹.

Silver/cellulose nanocomposite fibres, prepared using a simple reduction method, exhibit significant and competitive antibacterial activity against strains of bacteria, such as MRSA, which are proving resistant to broad-spectrum antibacterial agents.

Antibiotic pollution has become a serious concern due to the extensive use of antibiotics, their resistance to removal, and their detrimental effects on aquatic habitats and humans. Hence, developing an efficient antibiotic removal process for aqueous solutions has become vital. Amoxicillin (Amox) is one of the antibiotics that has been efficiently removed from an aqueous solution using hydroxyapatite nanoparticles (HAP NPs). The current study synthesizes and utilizes hydroxyapatite nanoparticles as a cost-effective adsorbent. Adsorbent dose, pH solution, initial Amox concentration, equilibrium time, and temperature are among the factors that have an evident impact on Amox antibiotic adsorption. The (200) mg dose, pH (5), temperature (25) °C, and time (120) min are shown to be the best-optimized values. The nonlinear Langmuir’s isotherm and pseudo-second-order kinetic models with equilibrium capacities of 4.01 mg/g are highly compatible with the experimental adsorption data. The experimental parameters of the thermodynamic analysis show that the Amox antibiotic adsorption onto HAP NPs powder is spontaneous and exothermic.