ZnFe2O4@SiO2@Tragacanth gum nanocomposite: synthesis and its application for the removal of methylene blue dye from aqueous solution

Fabricated Gamma-Alumina-Supported Zinc Ferrite Catalyst for Solvent-Free Aerobic Oxidation of Cyclic Ethers to Lactones

The aim of this work was to fabricate a new heterogeneous catalyst as zinc ferrite (ZF) supported on gamma-alumina (γ-Al2O3) for the conversion of cyclic ethers to the corresponding, more valuable lactones, using a solvent-free method and O2 as an oxidant. Hence, the ZF@γ-Al2O3 catalyst was prepared using a deposition-coprecipitation method, then characterized using TEM, SEM, EDS, TGA, FTIR, XRD, ICP, XPS, and BET surface area, and further applied for aerobic oxidation of cyclic ethers. The structural analysis indicated spherical, uniform ZF particles of 24 nm dispersed on the alumina support. Importantly, the incorporation of ZF into the support influenced its texture, i.e., the surface area and pore size were reduced while the pore diameter was increased. The product identification indicated lactone compound as the major product for saturated cyclic ether oxidation. For THF as a model reaction, it was found that the supported catalyst was 3.2 times more potent towards the oxidation of cyclic ethers than the unsupported one. Furthermore, the low reactivity of the six-membered ethers can be tackled by optimizing the oxidant pressure and the reaction time. In the case of unsaturated ethers, deep oxidation and polymerization reactions were competitive oxidations. Furthermore, it was found that the supported catalyst maintained good stability and catalytic activity, even after four cycles.

A novel nanocomposite containing zinc ferrite nanoparticles embedded in carboxymethylcellulose hydrogel plus carbon nitride nanosheets with multifunctional bioactivity

A novel and biologically active nanobiocomposite is synthesized based on carbon nitride nanosheet (g-C3N4) based carboxymethylcellulose hydrogels with embedded zinc ferrite nanoparticles. Physical-chemical aspects, morphological properties, and their multifunctional biological properties have been considered in the process of evaluation of the synthesized structure. The hydrogels' compressive strength and compressive modulus are 1.98 ± 0.03 MPa and 3.46 ± 0.05 MPa, respectively. Regarding the biological response, it is shown that the nanobiocomposite is non-toxic and biocompatible, and hemocompatible (with Hu02 cells). In addition, the developed material offers a suitable antibacterial activity for both Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli).

Green synthesis of ZnFe2O4 nanoparticles using plant extracts and their applications: A review

Magnetic nanoparticles, particularly ZnFe₂O₄ are of enormous significance in biomedical and water treatment fields. However, chemical synthesis of ZnFe₂O₄ nanoparticles endures some major limitations, e.g., the use of toxic substances, unsafe procedure, and cost-ineffectiveness. Biological methods are more preferable approaches since they take advantages of biomolecules available in plant extract serving as reducing, capping, and stabilizing agents. Herein, we review plant-mediated synthesis and properties of ZnFe₂O₄ nanoparticles for multiple applications in catalytic and adsorption performance, biomedical, catalyst, and others. Effect of several factors such as Zn²⁺/Fe³⁺/extract ratio, and calcination temperature on morphology, surface chemistry, particle size, magnetism and bandgap energy of obtained ZnFe₂O₄ nanoparticles was discussed. The photocatalytic activity and adsorption for removal of toxic dyes, antibiotics, and pesticides were also evaluated. Main results of antibacterial, antifungal and anticancer activities for biomedical applications were summarized and compared. Several limitations and prospects of green ZnFe₂O₄ as an alternative to traditional luminescent powders have been proposed.

A review on remediation of dye adulterated system by ecologically innocuous "biopolymers/natural gums-based composites"

The mitigation of wastewater exploiting biopolymers/natural gums-based composites is an appealing research theme in today's scenario. The following review presents a comprehensive description of the polysaccharides derived from biopolymers (chitosan, collagen, cellulose, starch, pectin, lignin, and alginate) and natural gums (guar, gellan, carrageenan, karaya, moringa oliefera, tragacanth, and xanthan gum). These biopolymers/natural gums-based composites depicted excellent surface functionality, non-toxicity, economic and environmental viability, which corroborated them as potential candidates in the decontamination process. The presence of -OH, -COOH, and -NH functional groups in their backbone rendered them tailorable for modification/functionalization, and anchor an array of pollutants via electrostatic interaction, hydrogen bonding, and Van der Waals forces. Further, due to these functional moieties, these bio-based composites revealed an excellent adsorption capacity than conventional adsorbents. This review provides an overview of the classification of biopolymers/natural gums based on their origin, different ways of their modification, and the remediation of dye-contaminated aqueous environments employing diverse bio-based adsorbents. The isotherm, kinetic modelling along with thermodynamics of the adsorption process is discussed. Additionally, the reusable efficacy of these bio-adsorbents is reviewed.

Green and Superior Adsorbents Derived from Natural Plant Gums for Removal of Contaminants: A Review

The ubiquitous presence of contaminants in water poses a major threat to the safety of ecosystems and human health, and so more materials or technologies are urgently needed to eliminate pollutants. Polymer materials have shown significant advantages over most other adsorption materials in the decontamination of wastewater by virtue of their relatively high adsorption capacity and fast adsorption rate. In recent years, "green development" has become the focus of global attention, and the environmental friendliness of materials themselves has been concerned. Therefore, natural polymers-derived materials are favored in the purification of wastewater due to their unique advantages of being renewable, low cost and environmentally friendly. Among them, natural plant gums show great potential in the synthesis of environmentally friendly polymer adsorption materials due to their rich sources, diverse structures and properties, as well as their renewable, non-toxic and biocompatible advantages. Natural plant gums can be easily modified by facile derivatization or a graft polymerization reaction to enhance the inherent properties or introduce new functions, thus obtaining new adsorption materials for the efficient purification of wastewater. This paper summarized the research progress on the fabrication of various gums-based adsorbents and their application in the decontamination of different types of pollutants. The general synthesis mechanism of gums-based adsorbents, and the adsorption mechanism of the adsorbent for different types of pollutants were also discussed. This paper was aimed at providing a reference for the design and development of more cost-effective and environmentally friendly water purification materials.

Locust Bean gum-based hydrogels embedded magnetic iron oxide nanoparticles nanocomposite: Advanced materials for environmental and energy applications

This paper reports a simple method of designing and synthesizing magnetic iron oxide (IO) integrated locust bean gum-cl-polyacrylonitrile hydrogel nanocomposites (LBG-cl-PAN/IONP) by in situ mineralization of iron ions in a hydrogel matrix. A two-step gel crosslink method followed by co-precipitation method was used to prepare these novel hydrogels embedded with magnetic iron oxide nanoparticles. The LBG-cl-PAN/IONP hydrogel nanocomposite (HNC) were tested in batch adsorption experiments for their ability to remove a cationic dyes, methylene blue (MB) & Methyl violet (MV), from aqueous solution. In order to analyze the LBG-cl-PAN/IONP HNC, FTIR, XRD, XPS, VSM, TEM, and EDX techniques were applied. Numerous operating parameters were studied, including the amount of adsorbent, the contact time, pH, temperature, the dye concentration, and the coexisting ion concentration. According to the Langmuir isotherm model, MB and MV had maximum monolayer adsorptive capacities of 1250 and 1111 mg/g, respectively. LBG-cl-PAN/IONP HNC controlled IONP oxidation as well as sustained adsorptive removal over a wide pH range (7-10). The key mechanism of adsorption consisted of electrostatic interaction and ion exchange. For successful use in successive cycles after regeneration using HNO₃ as eluent, the LBG-cl-PAN/IONP HNC can easily be reused. As a material, the LBG-cl-PAN/IONP HNC is a promising sorbent or composite material for removing toxic dyes from water, and therefore can be applied to enhance water and wastewater treatment technology. Additionally, we have briefly evaluated LBG-cl-PAN/IONP HNC for antibacterial and supercapacitor applications. According to our knowledge, this is the first report describing the use of LBG-cl-PAN/IONP HNC multifunctional efficacy as an excellent sorbent, antibacterial and electrochemical supercapacitor applications.

Application of magnetic carbon nanocomposite from agro-waste for the removal of pollutants from water and wastewater

Water pollution has significant impact on water usage, and various contaminants, such as organic and inorganic compounds, heavy metals, dyes, pharmaceuticals compounds, pathogens and radioactive compounds, are implicated. The quest for globalisation, structural developments and other related anthropogenic activities promote the release of contaminants that induce water pollution. Hence, treatment and remediation options that can remove pollutants from watercourses and wastewater have been developed. Applied nanotechnology using carbon nanocomposites has recently drawn attention because it has the advantages of low preparation cost, high surface area, pore volume and environmental stability. Magnetic carbon nanocomposites usually exhibit excellent performance in adsorbing contaminants from aqueous solutions, and thus expanding the use of nanotechnology in water treatment is of great importance. Therefore, this review explores the geographical outlook of water pollution, sources of water pollution and types of contaminants found in water and discusses the use of carbon nanocomposites as an emerging sustainable technology for water pollutant removal. The various properties of carbon-based composites influence the extent of pollutant adsorption during water treatment processes. Most carbon-based nanocomposites are generated from biomass produced by agro-waste materials. Magnetic activated carbon nanocomposites produced from walnut shells and rice husk waste can remove 78% of Cd(II) from contaminated aqueous systems. Magnetic nanocomposites from peanut shell, tea waste, curcumin nanoparticles, sunflower head waste, rice husk, hydrophyte biomass, palm waste and sugarcane bagasse facilitate hydrothermal carbonisation, chemical precipitation, co-precipitation, chemical activation, calcination and fast pyrolysis. These nanocomposites have benefitted wastewater treatment by increasing efficiency in removing pharmaceutical, dye and organic contaminants, such as promazine, ciprofloxacin, amoxicillin, rhodamine 6G, methyl blue, phenol and phenanthrene. Hence, this review discusses the relatively low costs, good biocompatibility, large surface-to-volume ratio, magnetic separation capability and reusability carbon materials and highlights the advantages of using magnetic carbon nanocomposites in the removal of contaminants from water or wastewater through adsorption mechanisms.

Ultrasonic-assisted synthesis of zeolite/activated carbon@MnO2 composite as a novel adsorbent for treatment of wastewater containing methylene blue and brilliant blue

In this study, zeolite/activated carbon@MnO₂ composite was used as a novel adsorbent to eliminate methylene blue (MB) and brilliant blue (BB) dyes from aqueous media. To this end, activated carbon (AC) was produced by Ziziphus Spina-Christi leaves and then used to synthesize zeolite/AC@MnO₂ composite. Various analyses such as BET, SEM, EDX, Map, FTIR, and XRD were performed to determine the surface features of the above composite. BET analysis indicated that the aforementioned composite has a mesoporous structure. Also, the best conditions for the adsorption of MB and BB dyes were obtained at pH of 9 and 2, temperature of 25 °C, adsorbent dosage of 1 and 2 g/L, initial dye concentration of 10 mg/L, and contact time of 40 and 60 min, respectively. Under optimal conditions, the utmost removal efficiency of MB and BB dyes using the zeolite/AC@MnO₂ composite was 98.43% and 96.54%, respectively, indicating significant adsorption efficiencies. Moreover, the utmost adsorption capacity of MB and BB dyes was 67.56 and 66.22 mg/g, respectively. Furthermore, intraparticle and film diffusion mechanisms were very important in the adsorption process. Besides, thermodynamic and equilibrium studies indicated that the adsorption process is exothermic, physical, and spontaneous. Generally, the aforementioned composite has a significant adsorption capacity and can be a suitable adsorbent to eliminate cationic dyes from industrial effluents.

Attachment of Tragacanth gum on polyester fabric through the synthesis of iron oxide gaining novel biological, physical, and thermal features

This study focuses on polyester fabric modification to produce environmentally-friendly multifunctional fabrics for varied applications. The nanoparticles of iron oxide were achieved from ferrous sulfate solution under alkaline conditions and applied to Tragacanth gum to form an efficient layer on the polyester surface. The synthesis of Fe₃O₄ nanoparticles with a crystal size of 12 nm was approved in the XRD spectra and iron oxide/Tragacanth gum nanocomposites with an agglomerated size of about 62 nm were confirmed by the SEM and EDX techniques. The formation of hydroxyl and iron oxide bands was observed in the FTIR and XPS patterns. The superparamagnetic behavior of treated samples exhibited by VSM with a magnetic saturation of 0.86 emu/g. The products showed an antibacterial activity (95 and 91%) toward Gram-positive and -negative bacteria. The absorbance intensity of methylene blue decreased from 2.6 to 1.6 by the treated sample. The synthesized nanoparticles on the treated surface indicated a lower release of iron ions and cell toxicity. The rate of cell duplication increased under a magnetic field with 60 Hz and 0.5 mT for 20 min/day. The product color changed from white to a brownish hue and the wetting capacity and thermal ability increased.

Novel magnetic organic-inorganic hybrids based on aromatic polyamides and ZnFe2O4 nanoparticles with biological activity

Magnetic nanoparticles were creatively selected as stable, inexpensive, biodegradable, facile recoverable, and functionalizable supports for a variety of synthetic and natural polymers. Herein, for the first time, aromatic polyamide was synthesized on the magnetic core of zinc iron oxide (ZnFe₂O₄). Terephthaloyl chloride and derivations of phenylenediamine were employed as monomers in this polymerization process. The toxicity of the synthesized hybrid at the highest concentration (1000 μg/ml) is 13.65% and on the other hand, the cell viability percentage is 86.35%. So, the prepared hybrid is biocompatible and non-toxic to Hu02 cells. Also, it has antibacterial ability against gram-positive and gram-negative bacteria. Because the results show that the minimum inhibitory concentration (MIC) of the synthesized polymer for bacteria such as Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, and Pseudomonas aeruginosa ATCC 27853 is in the range of 500-1000 µg/ml. Moreover, the hemolytic effect of ZnFe₂O₄ based hybrid was below 9% at the concentration of 1000 μg/ml. Therefore, it is compatible with red blood cells.