2D-layered Mg(OH)2 material adsorbing cellobiose via interfacial chemical coupling and its applications in handling toxic Cd2+ and UO22+ ions

Efficient Photocatalytic Dye Degradation and Bacterial Inactivation by Graphitic Carbon Nitride and Starch-Doped Magnesium Hydroxide Nanostructures

The removal of hazardous pollutants from water is becoming an increasingly interesting topic of research considering their impact on the environment and the ecosystem. This work was carried out to synthesize graphitic carbon nitride (g-C₃N₄) and starch-doped magnesium hydroxide (g-C₃N₄/St-Mg(OH)₂) nanostructures via a facile co-precipitation process. The focus of this study is to treat polluted water and bactericidal behavior with a ternary system (doping-dependent Mg(OH)₂). Different concentrations (2 and 4 wt %) of g-C₃N₄ were doped in a fixed amount of starch and Mg(OH)₂ to degrade methylene blue dye from an aqueous solution with bactericidal potential against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) pathogens. The textural structures, morphological evolutions, and optical characteristics of the as-prepared samples were analyzed using advanced characterization techniques. X-ray diffraction confirmed the hexagonal phase of Mg(OH)₂ with improved crystallinity upon doping. Fourier transform infrared spectroscopy revealed Mg(OH)₂ stretching vibrations and other functional groups. UV-visible spectroscopy exhibited a red shift (bathochromic effect) in absorption spectra representing the decrease in energy band gap (E _g). Photoluminescence patterns were recorded to study recombination of charge carriers (e^- and h⁺). A significant enhancement in photodegradation efficiency (97.62%) and efficient bactericidal actions against E. coli (14.10 mm inhibition zone) and S. aureus (7.45 mm inhibition zone) were observed for higher doped specimen 4% g-C₃N₄/St-Mg(OH)_2.

Efficient removal of Cd2+ from aqueous solution with a novel composite of silicon supported nano iron/aluminum/magnesium (hydr)oxides prepared from biotite

Taking low cost silicate minerals to develop efficient Cd²⁺ adsorption materials was favorable to the comprehensive utilization of minerals and remediation of environmental pollution. In this study, a composite of silicon supported nano iron/aluminum/magnesium (hydr)oxides was prepared with biotite by combining acid leaching and base precipitation process, which was used to remove Cd²⁺. Cd²⁺ adsorption behaviors were in accordance of pseudo-second order kinetic model and Langmuir model, and the obtained maximal Cd²⁺ adsorption capacity was 78.37 mg/g. Increasing pH and temperature could accelerate the removal of Cd²⁺. The activation energy was calculated as 66.05 kJ/mol, meaning that Cd²⁺ removal process was mainly depended on chemical adsorption. XRD and SEM results showed that this composite was a micro-nano structure of layered silica supported nano iron/aluminum/magnesium (hydr)oxides. Cd²⁺ removal mechanisms were consisted of surface complexation and ion exchange between Cd²⁺ and other metal ions, and the ion exchange interaction played the major role. These results indicated that a novel efficient utilization way for silicate minerals was developed.

Experimental and first-principle computational exploration on biomass cellulose/magnesium hydroxide composite: Local structure, interfacial interaction and antibacterial property

The specification of the local structure and clarification of interfacial interactions of biomass composites is of tremendous significance in synthesizing novel materials and advancing their performance in various demanding applications. However, it remains challenging due to the limitations of experimental techniques, particularly for the manner that biomass composites commonly have hydrogen bonds involved in the vicinity of active sites and interfaces. Herein, the cellulose/Mg(OH)₂ nanocomposite has been synthesized via a simple hydrothermal approach and examined by density functional theory (DFT) calculations. The composite exhibits a layered morphology; Mg(OH)₂ flakes are around 50 nm in size and well-dispersed. They either anchor onto the cellulose surface or intercalate between layers. The specific composite structure was confirmed theoretically, in line with XRD, SEM and TEM observations. The interfacial interactions were found to be hydrogen bonding. The average adsorption energy per hydroxyl group was computed to be within -0.47 and -0.26 eV for a composite model comprising three cellulose chains and a two-layered Mg(OH)₂ cluster. The combined computational/experimental results allow to postulate the antibacterial mechanism of the nanocomposite.