Study of molar properties of GO after doping with transition metals for photodegradation of fluorescent dyes

We synthesized graphene oxide (GO) doped with transition metal ions and characterized it using XPS, FT-IR, TGA/DTG, XRD, SEM, AFM, ICP-OES, UV/vis, and Raman spectroscopy. An intrinsic viscosity [η] of 0.002-0.012 g% @ 0.002 aq-GO was determined for viscosity average molecular weight (M _v) of GO at 288.15, 298.15, and 308.15 K. Mark-Houwink (M-H) constants k (cm³ g^-1) and a (cm³ mol g^-2) were calculated for 5-15 mg/100 mL polyvinylpyrrolidone (PVP), using 29, 40, 55 kg mol^-1 as markers for calculating M _v by fitting the [η] to the Mark-Houwink-Sakurada equation (MHSE). We obtained 48 134.19 g mol^-1 M _v at 298.15 K, and the apparent molar (V _{ϕ m} , cm³ mol^-1), limiting molar volumes (V ⁰ _GO)_GO⃑0, enthalpy (ΔH _m, J mol^-1), entropy (ΔS _m, J mol^-1 K^-1), viscosity (η _m, mPa s mol^-1), surface tension (γ _m, mN m^-1 mol^-1), friccohesity (σ _m, scm^-1 mol^-1), fractional volume (ϕ _m, cm³ mol^-1), isentropic compressibility (K _sϕ,m, 10^-4 cm s² g^-1 mol), infer GO molar consistency throughout the chemical processes. Molar properties (MPs) infer a GO monodispersion producing negative electrons (e^-) and positive holes (h⁺) under sunlight. The transition metal ions (Fe²⁺, Mn²⁺, Ni²⁺, Cr³⁺, TMI) doped onto GO (TMI-GO), can photodegrade methylene blue (MB) in 60 min compared with 120 min using GO alone. The 4011 C atoms, 688 hexagonal sheets, 222 π-conjugations, and 4011 FE were calculated from the 48 134.19 g mol^-1. The functional edges are the negative and positive holes generating centres of the GO 2D sheets.

A comparative study on aggregation and sedimentation of natural goethite and artificial Fe3O4 nanoparticles in synthetic and natural waters based on extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory and molecular dynamics simulations

Natural iron oxides nanomaterials have important roles in biogeochemical processes. In this study, the effects of pH, natural organic matter, and cations on aggregation and sedimentation of natural goethite and artificial Fe₃O₄ nanoparticles in water were investigated to learn more about the environmental behaviors of engineered and natural nanomaterials and how they differ. In addition, a novel extended DLVO theory that considered steric, gravitational, and magnetic attraction forces concurrently was specifically developed to provide mechanisms explanations. Specifically, Fe₃O₄ NPs were more likely than bulk goethite to aggregate (because of magnetic attraction interactions) at low HA concentrations and disperse at high HA concentrations. Besides, goethite was less prone to settle with the same concentration of NaCl than Fe₃O₄ NPs, but the opposite trend was found for the same concentration of CaCl₂ because of the difference in maximum net energy (barrier) and strong Ca²⁺ bridging effectiveness of goethite in CaCl₂ solution. Statistical models were established to evaluate colloidal stability of the particles. XPS and molecular dynamics simulation results suggested that ions were adsorbed onto particles via ionic polarization and that the binding free energies at high coverage followed the order Ca²⁺ > Na⁺ > Cl^- and presence of cation bridging between particles.

Design, preparation, and characterization of CS/PVA/SA hydrogels modified with mesoporous Ag2O/SiO2 and curcumin nanoparticles for green, biocompatible, and antibacterial biopolymer film

One of the most significant factors affecting the rapid and effective healing of wounds is the application of appropriate wound dressings. In the present study, novel antibacterial wound dressings are fabricated that consist of Chitosan (CS)/Polyvinyl alcohol (PVA)/Sodium Alginate (SA), which are all biocompatible, functionalized with mesoporous Ag₂O/SiO₂ and curcumin nanoparticles as reinforcements. In this research nanocomposites are fabricated (0 wt%, 5 wt%, 10 wt%, 15 wt%, and 20 wt% of Ag₂O/SiO₂). After the composition of nanocomposites using the cross-linked technique, Fourier Transform Infrared (FT-IR) spectroscopy is performed to confirm the functional groups that are added to the polymer at each step. X-ray diffraction (XRD) is done to show the crystallinity of Ag₂O/SiO₂. Field emission scanning electron microscopy (FE-SEM) studies are performed to demonstrate the morphology of the structure, Energy-dispersive X-ray spectroscopy (EDS) is done to examine the elements in the wound dressing and atomic force microscopy (AFM) study is performed to show surface roughness and pores. Then the nanocomposites with different weight percentages are cultured in three bacteria called Acinetobacter baumannii, Staphylococcus epidermidis, and Proteus mirabilis, all three of which cause skin infections. Finally, by performing the tensile test, the results related to the tensile strength of the wound dressings are examined. The results show that with the increase of Ag₂O/SiO₂, the mechanical properties, as well as the healing properties of the wound dressing, have increased significantly. Fabricating these nanocomposites helps a lot in treating skin infections.

CS/PVA/SA hydrogels modified with mesoporous Ag₂O/SiO₂ and curcumin nanoparticles for antibacterial biopolymer film.