Advancements in nanoparticle-modified zeolites for sustainable water treatment: An interdisciplinary review.

The contamination of water sources with heavy metals, dyes, and other pollutants poses significant challenges to environmental sustainability and public health. Traditional water treatment methods often exhibit limitations in effectively addressing these complex contaminants. In response, recent developments in nanotechnology have catalyzed the exploration of novel materials for water remediation, with nanoparticle-doped zeolites emerging as a promising solution. This comprehensive review synthesizes current literature on the integration of nanoparticles into zeolite frameworks for enhanced contaminant removal in water treatment applications. We delve into synthesis methodologies, elucidate mechanistic insights, and evaluate the efficacy of nanoparticle-doped zeolites in targeting specific pollutants, while also assessing considerations of material stability and environmental impact. The review underscores the superior adsorptive and catalytic properties of nanoparticle-doped zeolites, owing to their high surface area, tailored porosity, and enhanced ion-exchange capabilities. Furthermore, we highlight recent advancements in heavy metal and organic pollutant uptake facilitated by these materials. Additionally, we explore the catalytic degradation of contaminants through advanced oxidation processes, demonstrating the multifunctionality of nanoparticle-doped zeolites in water treatment. By providing a comprehensive analysis of existing research, this review aims to guide future developments in the field, promoting the sustainable utilization of nanoparticle-doped zeolites as efficient and versatile materials for water remediation endeavors.

Sustainable Zeolite-Silver Nanocomposites via Green Methods for Water Contaminant Mitigation and Modeling Approaches.

This study explores cutting-edge and sustainable green methodologies and technologies for the synthesis of functional nanomaterials, with a specific focus on the removal of water contaminants and the application of kinetic adsorption models. Our research adopts a conscientious approach to environmental stewardship by synergistically employing eco-friendly silver nanoparticles, synthesized using Justicia spicigera extract as a biogenic reducing agent, in conjunction with Mexican zeolite to enhance contaminant remediation, particularly targeting Cu2+ ions. Structural analysis, utilizing X-ray diffraction (XRD) and high-resolution scanning and transmission electron microscopy (TEM and SEM), yields crucial insights into nanocomposite structure and morphology. Rigorous linear and non-linear kinetic models, encompassing pseudo-first order, pseudo-second order, Freundlich, and Langmuir, are employed to elucidate the kinetics and equilibrium behaviors of adsorption. The results underscore the remarkable efficiency of the Zeolite-Ag composite in Cu2+ ion removal, surpassing traditional materials and achieving an impressive adsorption rate of 98% for Cu. Furthermore, the Zeolite-Ag composite exhibits maximum adsorption times of 480 min. In the computational analysis, an initial mechanism for Cu2+ adsorption on zeolites is identified. The process involves rapid adsorption onto the surface of the Zeolite-Ag NP composite, followed by a gradual diffusion of ions into the cavities within the zeolite structure. Upon reaching equilibrium, a substantial reduction in copper ion concentration in the solution signifies successful removal. This research represents a noteworthy stride in sustainable contaminant removal, aligning with eco-friendly practices and supporting the potential integration of this technology into environmental applications. Consequently, it presents a promising solution for eco-conscious contaminant remediation, emphasizing the utilization of green methodologies and sustainable technologies in the development of functional nanomaterials.

Characterization and Evaluation of Silver Concentrations in Hydroxyapatite Powders.

The goal of this study is to evaluate the influence of the concentration of silver on the structural and antimicrobial in vitro properties of silver-doped hydroxyapatite powders obtained using the precipitation method. Different concentrations of silver were evaluated to assess the antimicrobial properties. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, scanning electron microscopy (SEM), and dispersive energy spectroscopy (EDS) were used to characterize the powders. XRD and FTIR showed that the hydroxyapatite structure is not affected by the incorporation of silver; on the other hand, EDS showed the presence of silver in the powders. Antibacterial studies showed the efficiency of hydroxyapatite powders in inhibiting bacterial growth as silver concentration increases. According to the results, silver-doped hydroxyapatite powders are suggested for use in the prevention and treatment of infections in bone and dental tissues.

Green Ultrasound-Assisted Synthesis of Surface-Decorated Nanoparticles of Fe3O4 with Au and Ag: Study of the Antifungal and Antibacterial Activity.

This work proposes a sonochemical biosynthesis of magnetoplasmonic nanostructures of Fe3O4 decorated with Au and Ag. The magnetoplasmonic systems, such as Fe3O4 and Fe3O4-Ag, were characterized structurally and magnetically. The structural characterizations reveal the magnetite structures as the primary phase. Noble metals, such as Au and Ag, are present in the sample, resulting in a structure-decorated type. The magnetic measurements indicate the superparamagnetic behavior of the Fe3O4-Ag and Fe3O4-Au nanostructures. The characterizations were carried out by X-ray diffraction and scanning electron microscopy. Complementarily, antibacterial and antifungal assays were carried out to evaluate the potential properties and future applications in biomedicine.

Synthesis and Characterization of α-Al2O3/Ba-ß-Al2O3 Spheres for Cadmium Ions Removal from Aqueous Solutions.

The search for adsorbent materials with a certain chemical inertness, mechanical resistance, and high adsorption capacity, as is the case with alumina, is carried out with structural or surface modifications with the addition of additives or metallic salts. This research shows the synthesis, characterization, phase evolution and Cd(II) adsorbent capacity of α-Al2O3/Ba-ß-Al2O3 spheres obtained from α-Al2O3 nanopowders by the ion encapsulation method. The formation of the Ba-ß-Al2O3 phase is manifested at 1500 °C according to the infrared spectrum by the appearance of bands corresponding to AlO4 bonds and the appearance of peaks corresponding to Ba-O bonds in Raman spectroscopy. XRD determined the presence of BaO·Al2O3 at 1000 °C and the formation of Ba-ß-Al2O3 at 1600 °C. Scanning electron microscopy revealed the presence of spherical grains corresponding to α-Al2O3 and hexagonal plates corresponding to ß-Al2O3 in the spheres treated at 1600 °C. The spheres obtained have dimensions of 4.65 ± 0.30 mm in diameter, weight of 43 ± 2 mg and a surface area of 0.66 m2/g. According to the curve of pH vs. zeta potential, the spheres have an acid character and a negative surface charge of -30 mV at pH 5. Through adsorption studies, an adsorbent capacity of Cd(II) of 59.97 mg/g (87 ppm Cd(II)) was determined at pH 5, and the data were fitted to the pseudo first order, pseudo second order and Freundlich models, with correlation factors of 0.993, 0.987 and 0.998, respectively.

Sonochemical activation-assisted biosynthesis of Au/Fe3O4 nanoparticles and sonocatalytic degradation of methyl orange.

In this research, a sonochemical activation-assisted biosynthesis of Au/Fe3O4 nanoparticles is proposed. The proposed synthesis methodology incorporates the use of Piper auritum (an endemic plant) as reducing agent and in a complementary way, an ultrasonication process to promote the synthesis of the plasmonic/magnetic nanoparticles (Au/Fe3O4). The synergic effect of the green and sonochemical synthesis favors the well-dispersion of precursor salts and the subsequent growth of the Au/Fe3O4 nanoparticles. The hybrid green/sonochemical process generates an economical, ecological and simplified alternative to synthesizing Au/Fe3O4 nanoparticles whit enhanced catalytic activity, pronounced magnetic properties. The morphological, chemical and structural characterization was carried out by high- resolution Scanning electron microscopy (HR-SEM), Energy Dispersive X-Ray Spectroscopy (EDS) and X-Ray diffraction (XRD), respectively. Ultraviolet-visible (UV-vis) and X-ray photoelectron (XPS) spectroscopy confirm the Au/Fe3O4 nanoparticles obtention. The magnetic properties were evaluated by a vibrating sample magnetometer (VSM). Superparamagnetic behavior, of the Au/ Fe3O4 nanoparticles was observed (Ms = 51 emu/g and Hc = 30 Oe at 300 K). Finally, the catalytic activity was evaluated by sonocatalytic degradation of methyl orange (MO). In this stage, it was possible to achieve a removal percentage of 91.2% at 15 min of the sonocatalytic process (160 W/42 kHz). The initial concentration of the MO was 20 mg L-1, and the Fe3O4-Au dosage was 0.075 gL-1. The MO degradation process was described mathematically by four kinetic adsorption models: Pseudo-first order model, Pseudo-second order model, Elovich and intraparticle diffusion model.

Bactericidal Activity Study of ZrO2-Ag2O Nanoparticles.

In view of the continuous resistance to antibacterial agents by bacteria and the existing problems of silver nanoparticles as an antibacterial agent, this study reports on the synthesis of pure zirconium oxide, silver oxide, and ZrO2-Ag2O nanoparticles by sol-gel method. The nanoparticles were analyzed and tested for their antibacterial activity against gram-positive bacteria of Bacillus subtilis, Streptococcus mutans, Staphylococcus aureus, and gram-negative of Escherichia coli, Pseudomonas aeruginosa, and Klebsiella oxytoca. X-ray diffraction showed the monoclinic ZrO2, cubic Ag2O, and peaks corresponding to ZrO2 and Ag2O in their mixed samples. Scanning electron microscopy showed spherically shaped nanoparticles while dynamic light scattering analysis showed ZrO2 (76 nm), Ag2O (50 nm), and ZrO2-Ag2O samples between 14 and 42 nm. The Fourier Transformed Infrared spectroscopy spectra of ZrO2 gave bands at 480 cm-1 to 750 cm-1 (M-O stretching) with Ag2O at 580 cm-1, while ZrO2-Ag2O samples showed bands at 760 cm-1. The screening by agar diffusion assay revealed a pronounced increase in the antibacterial activity of ZrO2-Ag2O against all the tested bacteria when compared with the pure ZrO2 and Ag2O. The improved antibacterial activity of ZrO2-Ag2O largely results from the chemical stability conferred on it by the ZrO2 as observed from the zeta potential measurement.

Novel Route of Synthesis of PCL-CuONPs Composites With Antimicrobial Properties.

Nanoparticles of metals can be toxic to bacteria, showing biocidal activities at low concentrations. Metal, oxide, or compounds based on copper are applied like antimicrobial agents. The capacity of integration of metallic nanoparticles in polymer matrices has improved the antimicrobial behavior, resulting in the search for composites with increased bactericidal properties. A polycaprolactone (PCL) film polymer with copper oxide nanoparticles (CuONPs) was prepared. Dynamic light scattering analysis showed the sizes from 88 to 97 nm of CuONPs. Scanning electron microscopy (SEM) revealed CuONPs with semispherical shapes with diameter 35 nm. The prepared PCL-CuONPs exhibited a nanoporous structure by SEM. The antibacterial applicability of the composite was evaluated to determine the minimum inhibitory concentration in 6 different bacteria and the experimental tests were carried by disk diffusion and spectrophotometric methods. The PCL-CuONPs exhibit a considerable antibacterial effect in gram-positive bacteria in contrast to gram-negative bacteria. The preparation of PCL-CuONPs was simple, fast, and low cost for practical application as wound dressings.