Photocatalytic Degradation of Organic Pollutants-Nile Blue, Methylene Blue, and Bentazon Herbicide-Using NiO-ZnO Nanocomposite

Water pollution poses a significant threat to both human health and ecosystem integrity. Chemical pollutants such as dyes and pesticides affect the water quality and endanger aquatic life. Among the methods for water purification from organic pollutants, photodegradation is certainly a valid technique to decrease such contaminants. In this work, pristine NiO, ZnO, and NiO-ZnO photocatalysts were synthesized by the homogeneous co-precipitation method. X-ray diffraction confirms the formation of a photocatalyst consisting of ZnO (Hexagonal) and NiO (Cubic) structures. The crystalline size was calculated by the Scherrer formula, which is 19 nm for the NiO-ZnO photocatalyst. The band gap measurements of the prepared samples were obtained using the Tauc Plot, equation which is 2.93 eV, 3.35 eV and 2.63 eV for NiO, ZnO, and NiO-ZnO photocatalysts, respectively. The photocatalytic performance of NiO-ZnO nanocomposite was evaluated through the degradation of Methylene Blue and Nile Blue dyes under sunlight, and Bentazon herbicide under a UV light. Photocatalyst degradation efficiency was 95% and 97% for Methylene Blue and Nile Blue in 220 min under sunlight while a degradation of 70% for Bentazon after 100 min under UV light source was found.

Synthesis of Highly Luminescent Silica-Coated Upconversion Nanoparticles from Lanthanide Oxides or Nitrates Using Co-Precipitation and Sol-Gel Methods

Upconversion nanoparticles (UCNPs) are under consideration for their use as bioimaging probes with enhanced optical performance for real time follow-up under non-invasive conditions. Photostable and core-shell NaYF4:Yb3+, Er3+-SiO2 UCNPs obtained by a novel and simple co-precipitation method from lanthanide nitrates or oxides were herein synthesized for the first time. The sol-gel Stöber method followed by oven or supercritical gel drying was used to confer biocompatible surface properties to UCNPs by the formation of an ultrathin silica coating. Upconversion (UC) spectra were studied to evaluate the fluorescence of UCNPs upon red/near infrared (NIR) irradiation. ζ-potential measurements, TEM analyses, XRD patterns and long-term physicochemical stability were also assessed and confirmed that the UCNPs co-precipitation synthesis is a shape- and phase-controlling approach. The bio- and hemocompatibility of the UCNPs formulation with the highest fluorescence intensity was evaluated with murine fibroblasts and human blood, respectively, and provided excellent results that endorse the efficacy of the silica gel coating. The herein synthesized UCNPs can be regarded as efficient fluorescent probes for bioimaging purposes with the high luminescence, physicochemical stability and biocompatibility required for biomedical applications.

Preparation, Chromatic Properties Analysis and Proportioning Optimization of Co-Cr-Fe-Based Black Pigment

The utilization of Co-Cr-Fe-based black pigments bears considerable significance within the realm of commercial ceramic pigments, owing to their distinctive spinel structure, remarkable high-temperature stability, and exceptional chromatic attributes. This study delves into the synthesis of diverse black pigment configurations by employing the co-precipitation method, leveraging the interplay of these three metallic oxides. This investigation encompasses a comprehensive scrutiny of ion valences, crystal structures and parameters, colorimetric properties, and their interrelationships. The methodology integrates the response surface methodology (RSM) framework, using theoretical formulations to navigate the material ratios and elucidating the associations between the resultant compositions and color coordinate values, aligned with the CIE-Lab* colorimetric methodology. The derived predictive models yielded an optimized black pigment composition, characterized by heightened black intensity and a refined formulation.

Microstructure and Superconducting Properties of Bi-2223 Synthesized via Co-Precipitation Method: Effects of Graphene Nanoparticle Addition

The effects of graphene addition on the phase formation and superconducting properties of (Bi1.6Pb0.4)Sr2Ca2Cu3O10 (Bi-2223) ceramics synthesized using the co-precipitation method were systematically investigated. Series samples of Bi-2223 were added with different weight percentages (x = 0.0, 0.3, 0.5 and 1.0 wt.%) of graphene nanoparticles. The samples' phase formations and crystal structures were characterized via X-ray diffraction (XRD), while the superconducting critical temperatures, Tc, were investigated using alternating current susceptibility (ACS). The XRD showed that a high-Tc phase, Bi-2223, and a small low-Tc phase, Bi-2212, dominated the samples. The volume fraction of the Bi-2223 phase increased for the sample with x = 0.3 wt.% and 0.5 wt.% of graphene and slightly reduced at x = 1.0 wt.%. The ACS showed that the onset critical temperature, Tc-onset, phase lock-in temperature, Tcj, and coupling peak temperature, TP, decreased when graphene was added to the samples. The susceptibility-temperature (χ'-T) and (χ″-T) curves of each sample, where χ' and χ″ are the real and imaginary parts of the susceptibility, respectively, were obtained. The critical temperature of the pure sample was also measured.

Covalently-Bonded Coating of L-Arginine Modified Magnetic Nanoparticles with Dextran Using Co-Precipitation Method

In this study, L-arginine (Arg) modified magnetite (Fe₃O₄) nanoparticles (RMNPs) were firstly synthesized through a one-step co-precipitation method, and then these aminated nanoparticles (NPs) were, again, coated by pre-oxidized dextran (Dext), in which aldehyde groups (DextCHO) have been introduced on the polymer chain successfully via a strong chemical linkage. Arg, an amino acid, acts as a mediator to link the Dext to a magnetic core. The as-synthesized Arg-modified and Dext-coated arginine modified Fe₃O₄ NPs were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transformation infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and vibrating sample magnetometer (VSM). Both synthesized samples, XRD pattern and FT-IR spectra proved that the core is magnetite. FT-IR confirmed that the chemical bonds of Arg and Dext both exist in the samples. SEM images showed that the NPs are spherical and have an acceptable distribution size, and the VSM analysis indicated the superparamagnetic behavior of samples. The saturation magnetization was decreased after Dext coating, which confirms successive coating RMNPs with Text. In addition, the TGA analysis demonstrated that the prepared magnetic nanocomposites underwent various weight loss levels, which admitted the modification of magnetic cores with Arg and further coating with Dext.

Synthesis of Hydroxyapatite/Iron Oxide Composite and Comparison of Selected Structural, Surface, and Electrochemical Properties

The paper presents the synthesis of a hydroxyapatite/iron oxide composite utilizing the wet chemical method, as well as the comparison of several selected material characteristics. As follows from the literature reports, hydroxyapatite is a common mineral possessing numerous significant properties. Nowadays, there is an increase in the amount of research on possible modifications of this compound. The promising way to improve hydroxyapatite features is its combination with iron oxide. Particularly, there can be two forms that are distinguished, namely Fe₃O₄ and γ-Fe₂O₃. These oxides exhibit valuable properties, particularly magnetism. A combination of the mentioned materials leads to multifunctional composite formation with many potential applications, as follows from several studies. However, this area of science is not fully developed. There are still many aspects to be examined. The synthesized composite and its components were analyzed by employing the following methods. The X-ray diffraction analysis revealed formation of hydroxyapatite and Fe₂O₃ crystalline phases. Moreover, porosimetry proved a larger specific area for the composite sample in comparison with other materials. The results obtained using the SEM method confirmed an external layer of hydroxyapatite and spherical shapes of internal Fe₂O₃ particles. Furthermore, the X-ray photoelectron spectroscopy data presented characteristic peaks of Fe, Ca, P, and O atoms in all samples. The Fourier Transform Infrared spectra displayed all the specific vibrations typical of the analyzed materials. What is more, the Vibrating Sample Magnetometer method confirmed the paramagnetic nature of the samples. It could be concluded that the synthesized composite has intermediate properties between the components used in the formation process. The results suggest that these composites are superparamagnetic. This type of material architecture would be well suited for biomedical applications.

Green Synthesis of Iron-Doped Cobalt Oxide Nanoparticles from Palm Kernel Oil via Co-Precipitation and Structural Characterization

In this study, a bio-derived precipitating agent/ligand, palm kernel oil, has been used as an alternative route for the green synthesis of nanoparticles of Fe-doped Co3O4 via the co-precipitation reaction. The palm oil was extracted from dried palm kernel seeds by crushing, squeezing and filtration. The reaction of the palm kernel oil with potassium hydroxide, under reflux, yielded a solution containing a mixture of potassium carboxylate and excess hydroxide ions, irrespective of the length of saponification. The as-obtained solution reacts with an aqueous solution containing iron and cobalt ions to yield the desired metallo-organic precursor, iron cobalt carboxylate. Characterization of the precursors by IR and gas chromatography (GC) attests to the presence of carboxylate fatty acids in good agreement with the proportion contained in the oil, and ICP confirms that the metallic ratios are in the proportion used during the synthesis. Analysis of the products thermally decomposed between 400 °C and 600 °C by XRD, EDX, TEM and ToF-SIMS, established that cobalt iron oxide nanoparticles (Co(1-x)Fex)3O4 were obtained for x ≤ 0.2 and a nanocomposite material (Co(1-x)Fex)3O4/Fe3O4 for x ≥ 0.2, with sizes between 22 and 9 nm. ToF-SIMS and XRD provided direct evidence of the progressive substitution of cobalt by iron in the Co3O4 crystal structure for x ≤ 0.2.

Co-Doped NdFeO3 Nanoparticles: Synthesis, Optical, and Magnetic Properties Study

In this work, single-phase nanostructured NdFe_1-xCo_xO₃ (x = 0, 0.1, 0.2, and 0.3) perovskite materials were obtained by annealing stoichiochemistry mixtures of their component hydroxides at 750 °C for 60 min. The partial substitution of Fe by Co in the NdFeO₃ crystal lattice leads to significant changes in the structural characteristics, and as a consequence, also alters both the magnetic and optical properties of the resulting perovskites. The low optical band gap (E_g = 2.06 ÷ 1.46 eV) and high coercivity (H_c = 136.76 ÷ 416.06 Oe) give Co-doped NdFeO₃ nanoparticles a huge advantage for application in both photocatalysis and hard magnetic devices.

Quantitative Analysis of the Specific Absorption Rate Dependence on the Magnetic Field Strength in ZnxFe3-xO4 Nanoparticles

Superparamagnetic ZnxFe3-xO4 magnetic nanoparticles (0 ≤ x < 0.5) with spherical shapes of 16 nm average diameter and different zinc doping level have been successfully synthesized by co-precipitation method. The homogeneous zinc substitution of iron cations into the magnetite crystalline structure has led to an increase in the saturation magnetization of nanoparticles up to 120 Am2/kg for x ~ 0.3. The specific absorption rate (SAR) values increased considerably when x is varied between 0 and 0.3 and then decreased for x ~ 0.5. The SAR values are reduced upon the immobilization of the nanoparticles in a solid matrix being significantly increased by a pre-alignment step in a uniform static magnetic field before immobilization. The SAR values displayed a quadratic dependence on the alternating magnetic field amplitude (H) up to 35 kA/m. Above this value, a clear saturation effect of SAR was observed that was successfully described qualitatively and quantitatively by considering the non-linear field's effects and the magnetic field dependence of both Brown and Neel relaxation times. The Neel relaxation time depends more steeply on H as compared with the Brown relaxation time, and the magnetization relaxation might be dominated by the Neel mechanism, even for nanoparticles with large diameter.

Kinetic Studies on the Catalytic Degradation of Rhodamine B by Hydrogen Peroxide: Effect of Surfactant Coated and Non-Coated Iron (III) Oxide Nanoparticles

Iron (III) oxide (Fe₃O₄) and sodium dodecyl sulfate (SDS) coated iron (III) oxide (SDS@Fe₃O₄) nanoparticles (NPs) were synthesized by the co-precipitation method for application in the catalytic degradation of Rhodamine B (RB) dye. The synthesized NPs were characterized using X-ray diffractometer (XRD), vibrating sample magnetometer (VSM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Fourier transform infra-red (FT-IR) spectroscopy techniques and tested in the removal of RB. A kinetic study on RB degradation by hydrogen peroxide (H₂O₂) was carried out and the influence of Fe₃O₄ and SDS@Fe₃O₄ magnetic NPs on the degradation rate was assessed. The activity of magnetic NPs, viz. Fe₃O₄ and SDS@Fe₃O₄, in the degradation of RB was spectrophotometrically studied and found effective in the removal of RB dye from water. The rate of RB degradation was found linearly dependent upon H₂O₂ concentration and within 5.0 × 10^-2 to 4.0 × 10^-1 M H₂O₂, the observed pseudo-first-order kinetic rates (k_obs, s^-1) for the degradation of RB (10 mg L^-1) at pH 3 and temperature 25 ± 2 °C were between 0.4 and 1.7 × 10⁴ s^-1, while in presence of 0.1% w/v Fe₃O₄ or SDS@Fe₃O₄ NPs, k_obs were between 1.3 and 2.8 × 10⁴ s^-1 and between 2.6 and 4.8 × 10⁴ s^-1, respectively. Furthermore, in presence of Fe₃O₄ or SDS@Fe₃O₄, k_obs increased with NPs dosage and showed a peaked pH behavior with a maximum at pH 3. The magnitude of thermodynamic parameters E_a and ΔH for RB degradation in presence of SDS@Fe₃O₄ were 15.63 kJ mol^-1 and 13.01 kJ mol^-1, respectively, lowest among the used catalysts, confirming its effectiveness during degradation. Furthermore, SDS in the presence of Fe₃O₄ NPs and H₂O₂ remarkably enhanced the rate of RB degradation.

Superior Ion-exchange Property of Amorphous Aluminosilicates Prepared by a Co-precipitation Method

The development of inexpensive inorganic ion-exchangers for the purification of environmental pollutants is a social demand. Amorphous aluminosilicates with a relatively high homogeneous Al environment are prepared by a feasible co-precipitation method, i. e., mixing an acidic aluminum sulfate solution and basic sodium silicate solution, which exhibit excellent ion-exchange selectivity for Cs⁺ and Sr²⁺ . The K_d value for Sr²⁺ was comparable with that of zeolite 4A. The local structures and ion-exchange behavior of the amorphous aluminosilicates are systematically investigated. The ion-exchange property of the amorphous aluminosilicates can be tuned by changing the interaction between the exchangeable cation and the amorphous aluminosilicates. Also, the amorphous aluminosilicates can adsorb bulky cations that zeolites hardly adsorb due to the limitation of the miropore size of zeolites.

Synthesis, Structure, Morphology, and Luminescent Properties of Ba2MgWO6: Eu3+ Double Perovskite Obtained by a Novel Co-Precipitation Method

Eu³⁺ doped Ba₂MgWO₆ (BMW) double-perovskite was successfully synthesized for the first time by the co-precipitation method. The synthesis procedure, crystal structure, as well as morphology of obtained samples are presented. Domination of the ⁵D₀-⁷F₁ magnetic-dipole over forced electric-dipole transitions in the emission spectra indicates that Eu³⁺ ions are located in the high symmetry site with inversion center. Only one emission line assigned to the ⁵D₀-⁷F₀ transition was observed, confirming that europium substituted for only one host cation site. The photoluminescence excitation (PLE) spectrum is dominated by a strong and broad band related to the O^2- → Eu³⁺ and O^2- → W⁶⁺ charge transfer. The decay of the emission from the ⁵D₀ and ⁵D₁ levels was investigated. The temperature-dependent emission spectra showed that the T_0.5 is equal to 350 K. Extinguishing mechanisms of the Eu³⁺ luminescence in the studied host are discussed.

High-Performance Lithium-Rich Layered Oxide Material: Effects of Preparation Methods on Microstructure and Electrochemical Properties

Lithium-rich layered oxide is one of the most promising candidates for the next-generation cathode materials of high-energy-density lithium ion batteries because of its high discharge capacity. However, it has the disadvantages of uneven composition, voltage decay, and poor rate capacity, which are closely related to the preparation method. Here, 0.5Li₂MnO₃·0.5LiMn_0.8Ni_0.1Co_0.1O₂ was successfully prepared by sol–gel and oxalate co-precipitation methods. A systematic analysis of the materials shows that the 0.5Li₂MnO₃·0.5LiMn_0.8Ni_0.1Co_0.1O₂ prepared by the oxalic acid co-precipitation method had the most stable layered structure and the best electrochemical performance. The initial discharge specific capacity was 261.6 mAh·g⁻¹ at 0.05 C, and the discharge specific capacity was 138 mAh·g⁻¹ at 5 C. The voltage decay was only 210 mV, and the capacity retention was 94.2% after 100 cycles at 1 C. The suppression of voltage decay can be attributed to the high nickel content and uniform element distribution. In addition, tightly packed porous spheres help to reduce lithium ion diffusion energy and improve the stability of the layered structure, thereby improving cycle stability and rate capacity. This conclusion provides a reference for designing high-energy-density lithium-ion batteries.

Fabrication and Sintering Behavior of Er:SrF₂ Transparent Ceramics using Chemically Derived Powder

In this paper, we report the fabrication of high-quality 5 at. % Er³⁺ ions doped SrF₂ transparent ceramics, the potential candidate materials for a mid-infrared laser-gain medium by hot-pressing at 700 °C for 40 h using a chemically-derived powder. The phase structure, densification, and microstructure evolution of the Er:SrF₂ ceramics were systematically investigated. In addition, the grain growth kinetic mechanism of Er:SrF₂ was clarified. The results showed lattice diffusion to be the grain growth mechanism in the Er:SrF₂ transparent ceramic of which highest in-line transmittance reached 92% at 2000 nm, i.e., very close to the theoretical transmittance value of SrF₂ single crystal. Furthermore, the emission spectra showed that the strongest emission band was located at 2735 nm. This means that it is possible to achieve a laser output of approximately 2.7 μm in the 5 at. % Er³⁺ ions doped SrF₂ transparent ceramics.

The influence of ZnO-SnO2 nanoparticles and activated carbon on the photocatalytic degradation of toluene using continuous flow mode

The present study examined the gas-phase photocatalytic degradation of toluene using ZnO-SnO₂ nanocomposite supported on activated carbon in a photocatalytic reactor. Toluene was selected as a model pollutant from volatile organic compounds to determine the pathway of photocatalytic degradation and the factors influencing this degradation. The ZnO-SnO₂ nanocomposite was synthesized through co-precipitation method in a ratio of 2:1 and then supported on activated carbon. The immobilization of ZnO-SnO₂ nanocomposite on activated carbon was determined by the surface area and scanning electron micrograph technique proposed by Brunauer, Emmett, and Teller. The laboratory findings showed that the highest efficiency was 40% for photocatalytic degradation of toluene. The results also indicated that ZnO-SnO₂ nano-oxides immobilization on activated carbon had a synergic effect on photocatalytic degradation of toluene. Use of a hybrid photocatalytic system (ZnO/SnO₂ nano coupled oxide) and application of absorbent (activated carbon) may be efficient and effective technique for refinement of toluene from air flow.

Synthesized zinc peroxide nanoparticles (ZnO2-NPs): a novel antimicrobial, anti-elastase, anti-keratinase, and anti-inflammatory approach toward polymicrobial burn wounds

Increasing of multidrug resistance (MDR) remains an intractable challenge for burn patients. Innovative nanomaterials are also in high demand for the development of new antimicrobial biomaterials that inevitably have opened new therapeutic horizons in medical approaches and lead to many efforts for synthesizing new metal oxide nanoparticles (NPs) for better control of the MDR associated with the polymicrobial burn wounds. Recently, it seems that metal oxides can truly be considered as highly efficient inorganic agents with antimicrobial properties. In this study, zinc peroxide NPs (ZnO₂-NPs) were synthesized using the co-precipitation method. Synthesized ZnO₂-NPs were characterized by X-ray diffraction, Fourier transformed infrared, transmission electron microscopy, thermogravimetric analysis, differential scanning calorimetry, and ultraviolet-visible spectroscopy. The characterization techniques revealed synthesis of the pure phase of non-agglomerated ZnO₂-NPs having sizes in the range of 15–25 nm with a transition temperature of 211°C. Antimicrobial activity of ZnO₂-NPs was determined against MDR Pseudomonas aeruginosa (PA) and Aspergillus niger (AN) strains isolated from burn wound infections. Both strains, PA6 and AN4, were found to be more susceptible strains to ZnO₂-NPs. In addition, a significant decrease in elastase and keratinase activities was recorded with increased concentrations of ZnO₂-NPs until 200 µg/mL. ZnO₂-NPs revealed a significant anti-inflammatory activity against PA6 and AN4 strains as demonstrated by membrane stabilization, albumin denaturation, and proteinase inhibition. Moreover, the results of in vivo histopathology assessment confirmed the potential role of ZnO₂-NPs in the improvement of skin wound healing in the experimental animal models. Clearly, the synthesized ZnO₂-NPs have demonstrated a competitive capability as antimicrobial, anti-elastase, anti-keratinase, and anti-inflammatory candidates, suggesting that the ZnO₂-NPs are promising metal oxides that are potentially valued for biomedical applications.

Preparation of LuAG Powders with Single Phase and Good Dispersion for Transparent Ceramics Using Co-Precipitation Method

The synthesis of pure and well dispersed lutetium aluminum garnet (LuAG) powder is crucial and important for the preparation of LuAG transparent ceramics. In this paper, high purity and well dispersed LuAG powders have been synthesized via co-precipitation method with lutetium nitrate and aluminum nitrate as raw materials. Ammonium hydrogen carbonate (AHC) was used as the precipitant. The influence of aging time, pH value, and dripping speed on the prepared LuAG powders were investigated. It showed that long aging duration (>15 h) with high terminal pH value (>7.80) resulted in segregation of rhombus Lu precipitate and Al precipitate. By decreasing the initial pH value or accelerating the dripping speed, rhombus Lu precipitate was eliminated and pure LuAG nano powders were synthesized. High quality LuAG transparent ceramics with transmission >75% at 1064 nm were fabricated using these well dispersed nano LuAG powders.

Studies on the Preparation, Characterization, and Solubility of 2-HP-β-Cyclodextrin-Meclizine HCl Inclusion Complexes

Meclizine HCl is a poorly water-soluble drug having a very slow-onset of action. The effect of 2-hydroxypropyl-β-cyclodextrins and β-cyclodextrins on its aqueous solubility and dissolution rate was investigated. The phase solubility profile indicated that the solubility of Meclizine HCl was significantly increased in the presence of both 2-hydroxypropyl-β-cyclodextrin and β- cyclodextrin; an extend of increase being more for 2-hydroxypropyl-β-cyclodextrin. It was classified as AL-type, indicating the 1:1 stoichiometric inclusion complexes. The complexes formed were quite stable. The solid complexes prepared by physical mixtures, kneading methods, and co-precipitation methods were characterized using differential scanning calorimetry and FTIR. An in vitro study showed that the solubility and dissolution rate of Meclizine HCl were significantly improved by complexation with 2-hydroxypropyl-β-cyclodextrin. Tablet formulation using 1:1 kneading complex of Meclizine HCl and 2-hydroxypropyl-β-cyclodextrin with drug equivalent to 25 mg was prepared by a direct compression method. A dissolution study of prepared tablets was performed in 0.5% SLS in water (pH 7.0). Almost 96% drug was released from the formulation at the end of 30min. A comparison study of prepared tablets was done with marketed a Meclizine HCl 25 mg conventional tablet. From the results of dissolution study, it was found that the prepared formulation was showing better release, which was statistically significant P < 0.01 than a marketed tablet (paired t-test). Only 54% drug release was observed from the marketed tablet at the end of 30 min. Hence this study concludes that the solubility enhancement of Meclizine HCl could be successfully achieved using the inclusion complexation technique.