Magnetic chitosan stabilized Cu(II)-tetrazole complex: an effective nanocatalyst for the synthesis of 3-imino-2-phenylisoindolin-1-one derivatives under ultrasound irradiation

Deciphering the catalytic activity of nickel anchored on Fe3O4@SiO2@3-CPMS@L as a magnetically recoverable nanocatalyst for the efficacious reduction of 4-nitrophenol, nitrobenzene, and methyl orange

In this paper, a versatile heterogeneous nanocatalyst was fabricated employing a self-assembly technique. To commence, Fe3O4 MNPs were coated with a thin layer of SiO2 using the stobbers method. Subsequently, the surface was further functionalized with 3-CPMS, followed by a reaction with a Schiff base. Finally, nickel NPs were deposited on the surface through in situ deposition, forming the Fe3O4@SiO2@3-CPMS@L-Ni magnetic nanocatalyst. The architecture of this magnetic nanocatalyst was meticulously characterized through an array of sophisticated techniques: XRD, FT-IR, SEM, TEM, BET and VSM. The XRD diffraction pattern confirmed the presence of Fe3O4 MNPs, SiO2, and Ni peaks, providing evidence for successful synthesis. Moreover, the successful functionalization with a Schiff base was demonstrated by the presence of an azomethane peak in the FTIR spectra of the synthesized nanocatalyst. The fabricated nanocatalyst was adeptly utilized for the reduction of 4-NP, NB, and MO demonstrating a remarkably elevated rate of catalytic efficacy. Moreover, this catalyst was effortlessly retrievable through the application of an external magnet, and it maintained its catalytic prowess across at least six consecutive cycles. The utilization of water as an environmentally friendly solvent, coupled with the utilization of abundant and cost-effective nickel catalyst instead of the costly Pd or Pt catalysts, along with the successful recovery and scalability of the catalyst, render this method highly advantageous from both environmental and economic perspectives for the reduction of 4-NP, NB, and MO.

How the Chemical Properties of Polysaccharides Make It Possible to Design Various Types of Organic-Inorganic Composites for Catalytic Applications

Recently, the use of plant-origin materials has become especially important due to the aggravation of environmental problems and the shortage and high cost of synthetic materials. One of the potential candidates among natural organic compounds is polysaccharides, characterized by a number of advantages over synthetic polymers. In recent years, natural polysaccharides have been used to design composite catalysts for various organic syntheses. This review is devoted to the current state of application of polysaccharides (chitosan, starch, pectin, cellulose, and hydroxyethylcellulose) and composites based on their catalysis. The article is divided into four main sections based on the type of polysaccharide: (1) chitosan-based nanocomposites; (2) pectin-based nanocomposites; (3) cellulose (hydroxyethylcellulose)-based nanocomposites; and (4) starch-based nanocomposites. Each section describes and summarizes recent studies on the preparation and application of polysaccharide-containing composites in various chemical transformations. It is shown that by modifying polysaccharides, polymers with special properties can be obtained, thus expanding the range of biocomposites for catalytic applications.

Magnetic NH2-MIL-101(Al)/Chitosan nanocomposite as a novel adsorbent for the removal of azithromycin: modeling and process optimization

In the present study, the magnetic NH₂-MIL-101(Al)/chitosan nanocomposite (MIL/Cs@Fe₃O₄ NCs) was synthesized and used in the removal of azithromycin (AZT) from an aqueous solution for the first time. The as-synthesized MIL/Cs@Fe₃O₄ NCs was characterized by SEM, TEM, XRD, FTIR, BET, and VSM techniques. The effect of various key factors in the AZT adsorption process was modeled and optimized using response surface methodology based on central composite design (RSM-CCD). The low value of p-value (1.3101e-06) and RSD (1.873) parameters, along with the coefficient of determination > 0.997 implied that the developed model was well fitted with experimental data. Under the optimized conditions, including pH: 7.992, adsorbent dose: 0.279 g/L, time: 64.256 min and AZT concentration: 10.107 mg/L, removal efficiency and AZT adsorption capacity were obtained as 98.362 ± 3.24% and 238.553 mg/g, respectively. The fitting of data with the Langmuir isotherm (R²: 0.998, X²: 0.011) and Pseudo-second-order kinetics (R²: 0.999, X²: 0.013) showed that the adsorption process is monolayer and chemical in nature. ΔH° > 0, ΔS° > 0, and ∆G° < 0 indicated that AZT removal was spontaneous and endothermic in nature. The effect of Magnesium on AZT adsorption was more complicated than other background ions. Reuse of the adsorbent in 10 consecutive experiments showed that removal efficiency was reduced by about 30.24%. The performance of MIL/Cs@Fe₃O₄ NCs under real conditions was also tested and promising results were achieved, except in the treatment of AZT from raw wastewater.