Magnetic Nanoparticles Linked to Pyridinium Hydrotribromide Groups as Catalysts for Selective Oxidation of Alcohols and Protection of Alcohols

In this research, a novel magnetic nanocatalyst based on iron oxide nanoparticles linked with pyridinium hydrotribromide (Fe3O4@PyHBr3) was synthesized in three steps. In the first step, 3-(aminopropyl)triethoxysilane (APTES) was reacted with 4-(bromomethyl)pyridine hydrobromide. In the second step, the product obtained in the first step was reacted with iron oxide nanoparticles. In the last step, a grinding reaction was carried out with KBr and HIO4 in a mortar. The Fe3O4@PyHBr3 nanocatalyst was characterized by FT-IR, CHN, XRD, SEM, TGA and VSM analysis. The magnetic nanocatalyst was used as a catalyst for the selective oxidation of alcohols to aldehydes and ketones using 30% H2O2 as oxidant in a short time and with high yields. Moreover, no overoxidation of the alcohols was observed. The nanocatalyst was efficiently recycled in five consecutive cycles without significant loss of its catalytic activity. Moreover, trimethylsilylation and tetrahydropyranylation of alcohols were carried out in the presence of this nanocatalyst

Sulfonated Magnetic Nanocomposite Based on Reactive PGMA-MAn Copolymer@Fe 3

Chelating magnetic nanocomposites have been considered as suitable materials for removal of heavy metal ions for water treatment. In this work poly(glycidyl methacrylate-maleic anhydride) copolymer (PGMA-MAn) is modified with 4-aminobenzenesulfonic acid (ABSAc) and subsequently the product reacted with modified Fe3O4 nanoparticles and 1,2-ethanedithiol (EDT) in the presence of ultrasonic irradiation for preparation of tridimensional chelating magnetic nanocomposite. Synthesized magnetic nanocomposite was characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), vibrating sample magnetometer (VSM), energy dispersive X-ray analysis (EDX), elemental mapping analysis (EMA), Brunauer-Emmett-Teller (BET), and thermal gravimetric analysis (TGA). The adsorption behavior of Cu(II) ions was investigated by synthesized nanocomposite in various parameters such as pH, contact time, metal ion concentration, and adsorbent dosage. The equilibrium distribution coefficient (kd) was determined and the findings prove that the kd value is approximately high in the case of all selected metal ions. The synthesized nanocomposite exhibited good tendency for removing Cu(II) ions from aqueous solutions even at an acidic pH

Functionalization of polymers and nanomaterials for water treatment, food packaging, textile and biomedical applications: a review

AbstractThe inert nature of most commercial polymers and nanomaterials results in limitations of applications in various industrial fields. This can be solved by surface modifications to improve physicochemical and biological properties, such as adhesion, printability, wetting and biocompatibility. Polymer functionalization allows to graft specific moieties and conjugate molecules that improve material performances. In the last decades, several approaches have been designed in the industry and academia to graft functional groups on surfaces. Here, we review surface decoration of polymers and nanomaterials, with focus on major industrial applications in the medical field, textile industry, water treatment and food packaging. We discuss the advantages and challenges of polymer functionalization. More knowledge is needed on the biology behind cell–polymer interactions, nanosafety and manufacturing at the industrial scale

Conjugated polymer-based composite scaffolds for tissue engineering and regenerative medicine

Conjugated polymers such as polypyrrole, polyaniline, and polythiophene have developed as capable candidates for scaffold fabrication due to their electrical conductivity, tunable surface properties, and ability to deliver bioactive molecules. When blended with other biomaterials and nanoparticles enables the formation of composites that leverage the advantages of both components. The main focus areas of the review include the use of conjugated polymer-based composites (CPCs) for tissue engineering e.g., neural, cardiac, bone, and skin. Within each section, specific examples are provided of conjugated polymer-biomolecule composite systems that have been explored along with a discussion of their composition, fabrication, and performance for supporting cell growth and tissue regeneration. Finally, current challenges and future perspectives are discussed in applying CPCs toward engineering clinically relevant tissues and organs. Overall, this comprehensive review covers fundamental design considerations in developing conjugated polymer composite scaffolds and their emerging applications in tissue engineering

Molecularly Imprinted Magnetic Nanocomposite Based on Carboxymethyl Dextrin for Removal of Ciprofloxacin Antibiotic from Contaminated Water

Broad-spectrum antibiotics from the fluoroquinolone family have emerged as prominent water contaminants, among other pharmaceutical pollutants. In the present study, an antibacterial magnetic molecularly imprinted polymer (MMIP) composite was successfully fabricated using carboxy methyl dextrin grafted to poly(aniline-co-meta-phenylenediamine) in the presence of Fe3O4/CuO nanoparticles and ciprofloxacin antibiotic. The characteristics of obtained materials were investigated using FTIR, XRD, VSM, TGA, EDX, FE-SEM, zeta potential, and BETanalyses. Afterward, the MMIP’s antibacterial activity and adsorption effectiveness for removing ciprofloxacin from aqueous solutions were explored. The results of the antibacterial tests showed that MMIP had an antibacterial effect against Escherichia coli, a Gram-negative pathogen (16 mm), and Staphylococcus aureus, a Gram-positive pathogen (22 mm). Adsorption efficacy was evaluated under a variety of experimental conditions, including solution pH, adsorbent dosage, contact time, and initial concentration. The maximum adsorption capacity (Qmax) of the MMIP for ciprofloxacin was determined to be 1111.1 mg/g using 3 mg of MMIP, with an initial concentration of 400 mg/L of ciprofloxacin at pH 7, within 15 min, and agitated at 25 °C, and the experimental adsorption results were well-described by the Freundlich isotherm model. The adsorption kinetic data were well represented by the pseudo-second-order model. Electrostatic interaction, cation exchange, π-π interactions, and hydrogen bonding were mostly able to adsorb the majority of the ciprofloxacin onto the MMIP. Adsorption–desorption experiments revealed that the MMIP could be retrieved and reused with no noticeable reduction in adsorption efficacy after three consecutive cycles

Fabrication and Characterization of Dextrin-g-Polypyrrole/Graphene Oxide Nanocomposite for Effective Removal of Pb (II) and Methylene Blue Dye from Aqueous Solutions

Dextrin-g-polypyrrole/graphene oxides (PDGP/GO) nanocomposite was synthesized using in-situ polymerization and direct blending of PDGP and graphene oxide nanoparticles. The products were named nanocomposite 1 and nanocomposite 2, respectively. The prepared nanocomposites were characterized by Fourier transform infrared (FTIR) spectroscopy. Surface morphology and structure of nanocomposites were investigated by X-ray diffractometry (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The performance of the synthesized nanocomposites in removing Pb (II) and methylene blue dye from aqueous solutions was evaluated. The effect of pH, adsorbent dosage, contact time and contaminant concentration on Pb (II) and methylene blue uptake capacity was studied. On the other hand, the percentage removal of Pb (II) metal ion by nanocomposite 2 (96%) was higher than that of nanocomposite 1 (88%). The optimum condition for effective removal of methylene blue dye by nanocomposite 1 (94%) and nanocomposite 2 (98%) could be obtained at pH 8, nanocomposite dosage of 100 mg, contact time of 60 min and methylene blue concentration of 80 mg/L. Langmuir and Freundlich isotherm models, pseudo-first-order and pseudo-second-order kinetics equations and thermodynamic models were used to determine the mechanism of Pb (II) and methylene blue adsorption on the nanocomposite 2.  The results showed that the Langmuir isotherm, pseudo-first-order kinetic and spontaneous adsorption were suitable models for Pb (II) sorption on nanocomposite 2, while the Freundlich isotherm, pseudo-second-order kinetic and spontaneous adsorption were suitable models for methylene blue dye removal. Therefore, the PDGP/GO nanocomposite prepared by direct blending could be considered as a promising adsorbent for Pb (II) and methylene blue removal from aqueous solutions

Antioxidant, antibacterial and biodegradable hydrogel films from carboxymethyl tragacanth gum and clove extract: Potential for wound dressings application

Bioactive films based on sodium carboxymethyl tragacanth gum (CMT) and polyvinyl alcohol (PVA) enriched with clove extract (CE) for potential wound healing applications were fabricated by the solution casting method. The fabricated films were characterized by FTIR, XRD, EDX, SEM, and TGA analyses. The XRD pattern of CMT/PVA/CE5 % showed an amorphous structure with broad peaks, suggesting that the presence of CE led to a reduction in crystallinity and an increase in amorphousness in the polymer film. The fabricated films showed a high water absorption capacity and swelled up to 80 % over 24 h for the CMT/PVA/CE5 % formulation crosslinked with 15 % citric acid. Excellent biodegradability with 88 % was observed in soil over 40 days for CMT/PVA/CE5 %. The presence of CE in CMT/PVA improved the antioxidant activity by up to 92 % within 30 min. Strong antibacterial effects of CMT/PVA/CE5 % film were observed against Salmonella enterica and Staphylococcus aureus, with inhibition zone diameters of 20 mm and 18 mm, respectively. Across concentrations from 25 to 600 μg/mL, CMT/PVA/CE5 % films displayed over 80 % cell viability on cultured human dermal fibroblasts after 48 h. The results indicated that CMT/PVA/CE5 % bioactive film can be employed as effective, non-toxic wound dressings with infection prevention and healing promotion capabilities

Removal of <i>Amoxicillin</i> Antibiotic from Polluted Water by a Magnetic Bionanocomposite Based on Carboxymethyl Tragacanth Gum-<i>Grafted</i>-Polyaniline

Removal of antibiotics from contaminated water is very important because of their harmful effects on the environment and living organisms. This study describes the preparation of a bionanocomposite of carboxymethyl tragacanth gum-grafted-polyaniline and γFe2O3 using an in situ copolymerization method as an effective adsorbent for amoxicillin antibiotic remediation from polluted water. The prepared materials were characterized by several analyses. The vibrating sample magnetometer and thermal gravimetric analysis showed that the carboxymethyl tragacanth gum-grafted-polyaniline@ γFe2O3 bionanocomposite has a magnetization saturation of 25 emu g−1 and thermal stability with a char yield of 34 wt%, respectively. The specific surface area of bionanocomposite of about 8.0794 m2/g was obtained by a Brunauer–Emmett–Teller analysis. The maximum adsorption capacity (909.09 mg/g) of carboxymethyl tragacanth gum-grafted-polyaniline@ γFe2O3 was obtained at pH 7, an agitation time of 20 min, a bioadsorbent dose of 0.005 g, and amoxicillin initial concentration of 400 mg/L. The Freundlich isotherm and pseudo-second-order kinetic models were a better fit with the experimental data. The kinetic model showed that chemical adsorption is the main mechanism for the adsorption of amoxicillin on the bioadsorbent. In addition, the maximum adsorption capacity for amoxicillin compared to other reported adsorbents showed that the prepared bionanocomposite has a higher maximum adsorption capacity than other adsorbents. These results show that carboxymethyl tragacanth gum-grafted-polyaniline@ γFe2O3 would be a favorable bioadsorbent for the remediation of amoxicillin from contaminated water

Sulfonated Starch-Graft-Polyaniline@Graphene Electrically Conductive Nanocomposite: Application for Tyrosinase Immobilization

The interaction of tyrosinase with sulfonated starch-graft-polyaniline@graphene (SSt-g-PANI@G) nanocomposite was investigated by electrochemical methods. The activity of the immobilized tyrosinase (Tyase) was proved by the electrochemical detection of three substrates (L-dopa, caffeic acid, and catechol). The SSt-g-PANI@G nanocomposite was characterized by Fourier-transform infrared spectra (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray analysis (EDX), and thermogravimetric analysis (TGA). To immobilize tyrosinase on the surface of the nanocomposite, a simple drop-casting technique was used. The presence of sulfuric acid and hydroxyl groups in SSt, amine groups in PANI, and high surface-to-volume ratio and electrical conductivity of graphene in the prepared nanocomposite led to good enzyme immobilization on the electrode surface. The modified electrode showed a suitable catalytic effect on the electrochemical redox agent, compared with the bare electrode. The peak current responses for three substrates were studied with a calibration curve derived using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). In addition, the fabricated SSt-g-PANI@G/Tyase/GCE showed a more suitable response to catechol, L-dopa, and caffeic acid substrates, respectively