The present paper synthesized, characterized, and evaluated the performance of the novel biopolymeric membrane enriched with cellulose acetate and chitosan (CHI)-silver (Ag) ions in order to remove ...iron ion from the synthetic wastewater using a new electrodialysis system. The prepared membranes were characterized by Fourier Transforms Infrared Spectroscopy-Attenuated Total Reflection (FTIR-ATR), Thermal Gravimetric Analysis (TGA) and Differential Thermal Analysis (DSC), contact angle measurements, microscopy studies, and electrochemical impedance spectroscopy (EIS). The electrodialysis experiments were performed at the different applied voltages (5, 10, and 15 V) for one hour, at room temperature. The treatment rate (TE) of iron ions, current efficiency (IE), and energy consumption (Wc) were calculated. FTIR-ATR spectra evidenced that incorporation of CHI-Ag ions into the polymer mixture led to a polymer-metal ion complex formation within the membrane. The TGA-DSC analysis for the obtained biopolymeric membranes showed excellent thermal stability (>350 °C). The contact angle measurements demonstrated the hydrophobic character of the polymeric membrane and a decrease of it by CHI-Ag adding. The EIS results indicated that the silver ions induced a higher ionic electrical conductivity. The highest value of the iron ions treatment rate (>60%) was obtained for the biopolymeric membrane with CHI-Ag ions at applied voltage of 15 V.
There is an increased interest in recycling valuable waste materials for usage in procedures with high added values. Silica microparticles are involved in the processes of catalysis, separation, ...immobilization of complexants, biologically active compounds, and different nanospecies, responding to restrictive requirements for selectivity of various chemical and biochemical processes. This paper presents the surface modification of accessible and dimensionally controlled recycled silica microfiber with titanium dioxide. Strong base species in organic solvents: methoxide, ethoxide, propoxide, and potassium butoxide in corresponding alcohol, activated the glass microfibres with 12-13 µm diameter. In the photo-oxidation process of a toxic micro-pollutant, cyclophosphamide, the new composite material successfully proved photocatalytic effectiveness. The present work fulfills simultaneously two specific objectives related to the efforts directed towards a sustainable environment and circular economy: recycling of optical glass microfibers resulted as waste from the industry, and their usage for the photo-oxidation of highly toxic emerging micro-pollutants.
(1) Background: The standard treatment for periodontal disease, a chronic inflammatory state caused by the interaction between biofilms generated by organized oral bacteria and the local host defense ...response, consists of calculus and biofilm removal through mechanical debridement, associated with antimicrobial therapy that could be delivered either systemically or locally. The present study aimed to determine the effectiveness of a hyaluronic acid membrane matrix as a carrier for the controlled release of the active compounds of a formulation proposed as a topical treatment for periodontal disease, and the influence of pH on the complex system's stability. (2) Methods: The obtained hyaluronic acid (HA) hydrogel membrane with dispersed melatonin (MEL), metronidazole (MZ), and tetracycline (T) was completely characterized through FTIR, XRD, thermal analysis, UV-Vis and fluorescence spectroscopy, fluorescence microscopy, zeta potential and dielectric analysis. The MTT viability test was applied to check the cytotoxicity of the obtained membranes, while the microbiological assessment was performed against strains of
spp. and
spp. The spectrophotometric investigations allowed to follow up the release profile from the HA matrix for MEL, MZ, and T present in the topical treatment considered. We studied the behavior of the active compounds against the pH of the generated environment, and the release profile of the bioactive formulation based on the specific comportment towards pH variation. The controlled delivery of the bioactive compounds using HA as a supportive matrix was modeled applying Korsmeyer-Peppas, Higuchi, first-order kinetic models, and a newly proposed pseudo-first-order kinetic model. (3) Results: It was observed that MZ and T were released at higher active concentrations than MEL when the pH was increased from 6.75, specific for patients with periodontitis, to a pH of 7.10, characterizing the healthy patients. Additionally, it was shown that for MZ, there is a burst delivery up to 2.40 × 10
mol/L followed by a release decrease, while for MEL and T a short release plateau was recorded up to a concentration of 1.80 × 10
mol/L for MEL and 0.90 × 10
mol/L for T, followed by a continuous release; (4) Conclusions: The results are encouraging for the usage of the HA membrane matrix as releasing vehicle for the active components of the proposed topical treatment at a physiological pH.
The application of an active mixture of melatonin, hyaluronic acid and tetracycline, as antibiotic adjuvant, for scaling and root planing in periodontal disease is exploited. The hyaluronic acid gel ...has been used as matrix for this topical mixture. The mixture of active ingredients has been structurally studied applying UV-Vis and FT-IR spectrophotometry and fluorescence microscopy. Our target was to put in evidence if melatonin, hyaluronic acid and tetracycline were preserving their specific characteristics when they would be mixed together. The recorded results are encouraging as each active compound maintains its characteristic functional groups imparting their biological action. The improved topical treatment based on melatonin, hyaluronic acid and tetracycline is presenting itself as a promising candidate for improving the oral health for patients with periodontitis.
The polymer-inorganic nanoparticles composite membranes are the latest solutions for multiple physicochemical resistance and selectivity requirements of membrane processes. This paper presents the ...production of polysulfone-silica microfiber grafted with titanium dioxide nanoparticles (PSf-SiO2-TiO2) composite membranes. Silica microfiber of length 150–200 μm and diameter 12–15 μm were grafted with titanium dioxide nanoparticles, which aggregated as microspheres of 1–3 μm, applying the sol-gel method. The SiO2 microfibers grafted with nano-TiO2 were used to prepare 12% polysulfone-based nanocomposite membranes in N-methyl pyrrolidone through the inversion phase method by evaporation. The obtained nanocomposite membranes, PSf-SiO2-TiO2, have flux characteristics, retention, mechanical characteristics, and chemical oxidation resistance superior to both the polysulfone integral polymer membranes and the PSf-SiO2 composite membranes. The antimicrobial tests highlighted the inhibitory effect of the PSf-SiO2-TiO2 composite membranes on five Gram (-) microorganisms and did not allow the proliferation of Candida albicans strain, proving that they are suitable for usage in the oral environment. The designed membrane met the required characteristics for application as a functional barrier in guided bone regeneration.
In this paper, it is studied the influence of TiO2 nanoparticles content (0.2-5% wt:wt) on the electrical conductivities and the dielectric constants of poly (methyl methacrylate) (PMMA) ...nanocomposites used for 3D printing in dentistry. The nanocomposites films, which have been obtained applying the casting method followed by UV exposure, were mounted in a four electrodes cell for the electrochemical a.c. impedance analysis. The experimental data showed that both the dielectric constant and the electrical conductivity increase with increasing amounts of nano-TiO2 in nanocomposites. However, the change in the electrical conductivity is not significant for less 1% nano-titania added.
The present study introduces the process performances of nitrophenols pertraction using new liquid supported membranes under the action of a magnetic field. The membrane system is based on the ...dispersion of silver–iron oxide nanoparticles in n-alcohols supported on hollow microporous polypropylene fibers. The iron oxide–silver nanoparticles are obtained directly through cyclic voltammetry electrolysis run in the presence of soluble silver complexes (AgCl2−; Ag(S2O3)23−; Ag(NH3)2+) and using pure iron electrodes. The nanostructured particles are characterized morphologically and structurally by scanning electron microscopy (SEM and HFSEM), EDAX, XRD, and thermal analysis (TG, DSC). The performances of the nitrophenols permeation process are investigated in a variable magnetic field. These studies show that the flux and extraction efficiency have the highest values for the membrane system embedding iron oxide–silver nanoparticles obtained electrochemically in the presence of Ag(NH3)2+ electrolyte. It is demonstrated that the total flow of nitrophenols through the new membrane system depends on diffusion, convection, and silver-assisted transport.
The present work reports an efficient procedure for a simultaneous determination of melatonin (MEL) and hyaluronic acid (HA) mixture applying first derivative UV-Vis spectrophotometry. At selected ...wavelength (205 nm), the linearity range for each component of the mixture was established. The linear regression correlation coefficients for the direct UV-Vis spectra (RHA2 = 0.9627) and their first derivate (RHA2 = 0.9986) put in evidence a better fit for the derivative procedure. Through such simple analysis method, it was possible to emphasize that each component of MEL-HA mixture preserves its identity and characteristic properties. Consequently, the association of MEL and HA biomolecules could be used for obtaining a complex therapeutic agent with extensive applications in dental medicine.
Knee osteoarthritis (KOA) is a chronic multifactorial pathology and a current and essential challenge for public health, with a negative impact on the geriatric patient's quality of life. The ...pathophysiology is not fully known; therefore, no specific treatment has been found to date. The increase in the number of newly diagnosed cases of KOA is worrying, and it is essential to reduce the risk factors and detect those with a protective role in this context. The destructive effects of free radicals consist of the acceleration of chondrosenescence and apoptosis. Among other risk factors, the influence of redox imbalance on the homeostasis of the osteoarticular system is highlighted. The evolution of KOA can be correlated with oxidative stress markers or antioxidant status. These factors reveal the importance of maintaining a redox balance for the joints and the whole body's health, emphasizing the importance of an individualized therapeutic approach based on antioxidant effects. This paper aims to present an updated picture of the implications of reactive oxygen species (ROS) in KOA from pathophysiological and biochemical perspectives, focusing on antioxidant systems that could establish the premises for appropriate treatment to restore the redox balance and improve the condition of patients with KOA.
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