A facile approach for synthesizing Fe-based layered double hydroxides with high purity and its exfoliation

Eco-friendly synthesis of the Li/Al in nonionic surfactant-based vesicles (niosomes) modified with graphene oxide quantum dot nanostructures for controlled released of chlorpheniramine maleate

The aim of the present work was the preparation of Li/Al nanoparticles (NPs) functionalized with graphene oxide quantum dots (GOQDs) for the controlled release of chlorpheniramine maleate (CPAM). The role of lemon and egg white extracts as oxidation agents were investigated for the morphology and particle size of the products. GOQDs were synthesized using green, environmentally friendly, and cost-effective precursors. This work demonstrates that Li/Al NPs functionalized with graphene oxide as a nanolayer structure can be used as efficient nanocarriers for loading and delivery of CPAM as water-insoluble aromatic drugs The final products were identified with X-ray diffraction, scanning electron microscopy, atomic force microscopy, ultraviolet-visible spectroscopy, dynamic light scattering, thermogravimetric analysis, and transmission electron microscopy nitrogen adsorption [i.e. Brunauer-Emmett-Teller (BET) surface area analysis] techniques. The calibration curve for Li/Al nanoparticles functionalized with GOQDs for controlled released of CPAM was calculated as y = 0.0137x + 0.0103 with R²  = 0.9995. The data found through BET and Barrett-Joyner-Halenda analysis using the adsorption/desorption isotherm method demonstrated by total pore volumes and dead volume were calculated respectively as 0.162 nm² , 0.0439 cm³ g^-1 . The mean pore diameter was calculated as 20.33 nm using BET isotherm data.

Catalytic conversion of high-GWP gases N2O and CH4 to syngas (H2 + CO) on SiO2@Ni-Cr layered nano-oxide-coated monolithic catalyst

Layered double hydroxides (LDHs) are 2D nano-sheets where different M²⁺ and M³⁺ metal cations are uniformly distributed in Mg(OH)₂ brucite-like sheets and various charge-compensating anions (A^n-) are present in their interlayer spaces. This work includes preparation of different SiO₂@Ni/Cr mixed-metal layered nano-oxide-type catalysts by the calcination of SiO₂@Ni-Cr LDH nano-composite-based alcogel coated over a honeycomb monolithic substrate and their use as a catalytic device for the study of catalytic partial oxidation (CPO) of CH₄ both in the presence of O₂ and in the presence of N₂O under atmospheric pressure at different temperatures not exceeding 500 °C to study the effect of N₂O on the CPO of CH₄. It was observed that in the presence of O₂ the yield of syngas (H₂ + CO) did not exceed 90% whereas in the presence of N₂O about 99.9% syngas (H₂ + CO) was observed. The selectivity towards syngas production reached a maximum value when an optimal reaction condition was maintained at 1:1 CH₄:N₂O mol ratio with a temperature of 500 °C. XPS analysis showed that a NiO-type compound formed on the decomposition of the LDH component after H₂ treatment was reduced to disperse Ni⁰_, which acted as an active catalytic species. Graphical abstract Schematic representation of catalytic partial oxidation of CH₄ in the presence of N₂O by SiO₂@Ni-Cr-LDH-based mixed-metal nano-oxide.

Exfoliated Mg-Al-Fe layered double hydroxides/polyether sulfone mixed matrix membranes for adsorption of phosphate and fluoride from aqueous solutions

Mg-Al-Fe layered double hydroxides (LDHs) were exfoliated and incorporated in polyether sulfone membranes for the removal of phosphate and fluoride for the first time. The exfoliation methods, coagulation bath, LDH amount, interfering ions, adsorption isotherm, desorption and reuse of the membranes were investigated. It was found that LDHs could be quickly exfoliated in formamide/N,N-dimethylformamide (DMF) solvent mixtures with sodium carboxymethyl cellulose as a stabilizer. The membranes displayed much higher adsorption capacity for phosphate (5.61mg/g) and faster adsorption rate than the un-exfoliated materials. With increased DMF content in the coagulation bath, the static and dynamic adsorption capacity rose. Interference from Cl^- and SO₄^2- (50mg/L) on adsorption of phosphates was not apparent. The membranes displayed excellent reusability in dynamic adsorption/desorption. The membranes also showed high adsorption capacity for fluorides (1.61mg/g).

Development of Mg–Al–La tri-metal mixed oxide entrapped in alginate for removal of fluoride from wastewater

New biopolymer beads, composite of Mg–AL–La tri-metal oxides and alginate, were synthesized, characterized and tested for their fluoride removal efficiency from wastewater. The maximum adsorption capacity of the adsorbent was 30.9 mg g⁻¹.

Efficient catalytic oxidation of alcohol to carbonyl compounds over CoFe hydrotalcites

A series of CO₃²⁻–Co_xFe–LDHs (x = 2, 3, 4 and 5) compounds with different Co/Fe ratios have been prepared, characterized and introduced into the selective oxidation of alcohols by tert-butylhydroperoxide.