Metal Ions Zn Research Articles

Investigation of structural, magnetic and morphological properties of Zinc and Cobalt-doped Nickel Ferrites

Abstract Nickel Ferrite nanocrystalline material doped with transition metal ions (Zn2+, Co2+) was obtained by chemical combustion method using respective nitrate hexahydrates and glycine as fuel. The phase purity of the prepared ceramic samples was ascertained using Powder X-ray diffraction (XRD) exhibiting an inverse cubic spinel structure with space group Fd 3 ‾ $\overline{\mathrm{3}}$ m. Lattice parameters follow the Vegard law, indicating a consistent lattice expansion. The formation of porous nanocrystalline ferrite was confirmed by Scanning Electron Microscopy (SEM) images and corroborated by Williamson-Hall analysis. Raman Spectroscopic analysis identified characteristic bands corresponding to vibrational modes of nickel ferrite (NiFe2O4) and revealed shifts in the peak position with doping by zinc (Zn) and cobalt (Co). Vibrating Sample magnetometry (VSM) analysis indicated varied magnetic behaviour with different dopants and concentrations highlighting the influence of cation substitution on magnetic properties. The specific saturation magnetization (M s ), remanent magnetization (M r ) and coercivity (H c ) are improved by the substitution of Zn2+ and Co2+ ions. This simple and cost-effective preparation technique holds promise for synthesizing high-quality nickel ferrite, which could find applications in magnetic and electronic devices.

Investigation on the interaction mechanism of trilobatin with pepsin and trypsin by multi-spectroscopic and molecular docking methods

Pepsin and trypsin are noteworthy for the digestion of proteins in the human body. Trilobatin is a dihydrochalone that has anti-obesity, antioxidant, and anti-diabetes functions. The interaction of trilobatin and pepsin or trypsin is not currently being explored. Therefore, in this research multiple methods involving fluorescence spectroscopy, synchronous fluorescence spectroscopy, ultraviolet–visible (UV–Vis) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, circular dichroism (CD) and molecular docking were employed for studying the interaction between trilobatin and pepsin or trypsin. During the interaction between trilobatin and pepsin or trypsin, the quenching type was static quenching and a single binding site existed. The binding constants (Ka) values were 2.177 and 3.028 × 104 L/mol in trilobatin-pepsin and trilobatin-trypsin system at 298 K, respectively. However, the presense of metal ions (Zn2+, Ca2+ and K+) decreased the binding of trilobatin to pepsin and trypsin. The complex between trilobatin and pepsin was generated typically through hydrogen bonding and van der Waals force (ΔH° < 0 and ΔS° < 0), in comparison the complex between trilobatin and trypsin was established chiefly through hydrogen bond and hydrophobic force (ΔH° > 0 and ΔS° > 0). The data from UV–Vis, synchronous fluorescence, FT-IR and CD spectra indicated that trilobatin reduced the hydrophobicity of Tyrosine (Tyr) residues of pepsin and trypsin. Furthermore, trilobatin altered the secondary structures of pepsin and trypsin. Meanwhile, trilobatin changed the conformation of pepsin and trypsin so that the viscosity of the interaction systems decreased with increased of trilobatin concentration. The molecular docking modeling identified that the trilobatin interacted with amino acid residues around pepsin and trypsin. This work consistently showed the interaction between trilobatin and pepsin or trypsin, in addition to offering valuable information for the application of trilobatin.

Impact of Metal Ions, Peroxymonosulfate (PMS), and pH on Sulfolane Degradation by Pressurized Ozonation

This study investigated the degradation of sulfolane using pressurized ozonation under varying initial concentrations and the influence of different catalysts and peroxymonosulfate activation methods on the degradation efficiency. Initial sulfolane concentrations of 1 mg L−1, 20 mg L−1, and 100 mg L−1 were tested over 120 min, revealing a degradation efficiency of 73%, 41%, and 18%, respectively. The addition of various metal ions (Zn2+, Mg2+, Cu2+, Ni2+, and Co2+) demonstrated that only zinc and magnesium enhanced degradation, with zinc achieving a 92% removal efficiency and magnesium achieving 86%. Different doses of magnesium and zinc were further tested, showing optimal degradation at specific concentrations. The combination of PMS with ozonation was explored, revealing that zinc activation did not significantly enhance degradation, while NaOH activation achieved near-total degradation, with a 100 mg L−1 NaOH concentration. Varying PMS concentrations indicated that altering pH was more effective than changing PMS dosage. Finally, the impact of pH changes in both reverse osmosis water and tap water matrices confirmed that higher pH levels significantly improved degradation efficacy, achieving up to 98% removal with NaOH concentrations of 50 mg L−1 in reverse osmosis water. These results suggest that optimizing pH and catalyst type are critical for enhancing sulfolane degradation in pressurized ozonation systems.

Ultra‐High Metal‐Ion Selectivity Induced by Intramolecular Cation‐π Interactions for the One‐Pot Synthesis of Precise Heterometallic Architectures

AbstractHeterometallic supramolecules, known for their unique synergistic effects, have shown broad applications in photochemistry, host‐guest chemistry, and catalysis. However, there are great challenges to precisely construct heterometallic supramolecules rather than a statistical mixture, due to the limited metal‐ion selectivity of coordination units. In particular, heterometallic architectures precisely encoded with different metal ions usually fail to form in a one‐pot method when only one type of coordinated motif exists due to its poor metal‐ion selectivity. Herein, we propose an effective intramolecular cation‐π (ICπ) strategy and successfully constructed the heterometallic supramolecule Zn2Cu4L34 by the one‐pot self‐assembly of tritopic terpyridyl ligand L3 with Zn(II) and Cu(II), following a clear self‐assembly mechanism in which only thermodynamic dimers ZnL12 and Cu2L22 were constructed with model ligands L1, L2, Zn(II) and Cu(II) with perfect self‐sorting and an ultra‐high metal‐selectivity feature. The successful construction of the heterometallic supramolecule Zn2Cu4L34, in which the definite sequence of metal ions Zn(II) and Cu(II) is encoded in the one‐pot method, will offer a novel approach to precisely construct heterometallic architectures.

Ultra-High Metal-Ion Selectivity Induced by Intramolecular Cation-π Interactions for the One-Pot Synthesis of Precise Heterometallic Architectures.

Heterometallic supramolecules, known for their unique synergistic effects, have shown broad applications in photochemistry, host-guest chemistry, and catalysis. However, there are great challenges to precisely construct heterometallic supramolecules rather than a statistical mixture, due to the limited metal-ion selectivity of coordination units. In particular, heterometallic architectures precisely encoded with different metal ions usually fail to form in a one-pot method when only one type of coordinated motif exists due to its poor metal-ion selectivity. Herein, we propose an effective intramolecular cation-π (ICπ) strategy and successfully constructed the heterometallic supramolecule Zn2Cu4L34 by the one-pot self-assembly of tritopic terpyridyl ligand L3 with Zn(II) and Cu(II), following a clear self-assembly mechanism in which only thermodynamic dimers ZnL12 and Cu2L22 were constructed with model ligands L1, L2, Zn(II) and Cu(II) with perfect self-sorting and an ultra-high metal-selectivity feature. The successful construction of the heterometallic supramolecule Zn2Cu4L34, in which the definite sequence of metal ions Zn(II) and Cu(II) is encoded in the one-pot method, will offer a novel approach to precisely construct heterometallic architectures.

Mechanochemical Synthesis of High-Entropy MOF-74 with Multiple Active Sites for CO2 Adsorption and Synergistic Conversion.

Compared with monometallic metal-organic frameworks (MOFs), the synergistic effect of multiple metals significantly enhances the catalytic performance of the CO2 cycloesterification reaction, leading to improved CO2 adsorption and catalytic conversion capabilities. To investigate this concept, a high-entropy MOF-74 (HE-MOF-74) with a uniform distribution of five distinct metal ions (Zn2+, Mg2+, Ni2+, Co2+, and Cu2+) was successfully synthesized using a straightforward mechanical ball milling technique and comprehensively characterized (including structural, morphological, and physicochemical properties). The results reveal that HE-MOF-74 exhibits significantly increased specific surface area and CO2 adsorption capacity compared with those of monometallic MOF-74. The presence of multiple unsaturated metal centers as Lewis acid sites, oxygen atoms linking the metals, and ligand-based hydroxyl groups serving as base sites enable efficient immobilization of CO2 into cyclic carbonate. This study introduces a novel synthetic approach for the green and efficient production of HE-MOF-74 and proposes a new application for CO2 utilization.

In situ synthesis of Chitin/ZIF-67 composite hydrogel for efficient recovery of high purity acetonitrile by removal of Zn2+ and Ag+

The improper disposal of waste high purity acetonitrile (HPA) not only causes environmental degradation but also poses significant risks to human health. One of the major challenges in the recycling and reuse of waste HPA is the removal of trace metal ions. In this study, we successfully fabricated a chitin/ZIF-67 composite hydrogel (CZ-n) by one pot in situ synthesis method for the purification and recovery of waste HPA for the first time. ZIF-67 was embedded into chitin through hydrogen bonding and coordination and provided more active adsorption sites, which resulted in CZ-3 with higher adsorption capacity than CZ-0. The maximum adsorption capacities of CZ-3 for Zn2+ and Ag+, as determined by fitting the Langmuir model, were 85.46 mg·g-1 and 91.26 mg·g-1, respectively. CZ-3 was able to effectively decrease the metal ion (Zn2+ and Ag+) concentration to below 10 ppb within 24 h through a monolayer adsorption process using chelation. Furthermore, the adsorption capacity remained satisfactory even in the presence of an equivalent concentration of NaCl, and CZ-3 exhibited remarkable reusability, with a removal rate exceeding 80 % after five cycles. Additionally, it also displayed notable biodegradability, with complete degradation observed within 60 days. These results indicated that CZ-3 could be a potential absorbent in the purification and recovery of waste HPA.

Supercritical carbon dioxide chelation extraction of heavy metal ions from drilling fluid waste: Experiment and simulation

This study evaluates the application of supercritical carbon dioxide chelation extraction technology for treating heavy metal ions (Zn2+ and Cr3+) in drilling fluid waste. Through a combination of experimental and molecular dynamics simulation methods, the influence of extraction parameters (temperature, pressure, duration, and chelating agents) on the extraction efficiency are investigated. Findings show that increased duration and pressure significantly improve extraction efficiency, while temperature has a complex effect, initially increasing efficiency but plateauing and slightly decreasing at higher temperatures. The optimum extraction condition with pressure of 220 bar, temperature 348.15 K and an extraction duration of 70 min using ethylene diamine tetraacetic acid (EDTA) as the chelating agent has been determined. Importantly, molecular simulation analysis revealed that citric acid outperforms EDTA in terms of Zn2+ and Cr3+ aggregation by forming larger aggregates with greater numbers of molecules while reducing overall aggregate count. Furthermore, optimization of extraction pressure in the EDTA system shows potential benefits. These results suggest that supercritical carbon dioxide chelation extraction technology has strong potential for environmentally friendly and reliable waste management in the drilling industry. This study represents a significant step forward in developing sustainable solutions for heavy metal removal from drilling fluid waste.

Novel Cu(II) and Zn(II) Nanocomplexes Based on 5,6‐Diphenyl‐1,2,4‐Triazine: Preparation, Spectroscopic, TD‐DFT Calculations, Molecular Docking and Solvatochromic Studies

ABSTRACTThe reaction between 2‐hydroxy‐1‐naphthaldehyde and 3‐hydrazino‐5,6‐diphenyl‐1,2,4‐triazine produced a novel hydrazone ligand (DTHMN), which reacted with Cu(II) and Zn(II) metal ion in molar ratio 1:1, giving octahedral Cu(II)‐DTHMN and tetrahedral Zn(II)‐DTHMN nanosized complexes. The structural geometries have been elucidated on the basis of elemental analysis, nuclear magnetic resonance, infrared, electronic, and electron spin resonance spectra, and magnetic and molar conductance measurements as well as x‐ray diffraction and thermal analysis. TEM analysis showed that Zn(II)‐DTHMN complex has nano‐rode morphology shape. On the other hand, Cu(II)‐DTHMN has sphere shape within nanodomain. The DTHMN ligand exhibits ONN chelating sites through N‐triazine ring, azomethine nitrogen, and deprotonated OH group, forming the mononuclear metal complexes. The synthesized compounds showed a distinct solvatochromic behavior in different polar solvents. A bathochromic alteration is observed when moving from less to high polar solvents, indicating strong solute–solvent interactions accompanied by intramolecular charge transfer (ICT). The ground and excited state dipole moments of these compounds were determined experimentally by solvatochromic shift method using Bilot–Kawski, Lippert–Mataga, Bakhshiev, and Kawski–Chamma–Viallet functions and a microscopic Reichardt's solvent polarity parameter (ETN). The dipole moment is increased significantly upon excitation referring to stabilizing the excited species includes n–π* transition by polarity of solvent. The experimental results are generally consistent with those values obtained by B3LYP/GENECP method at 6‐311G(d,p) basis set for C, H, N, and O atoms and SDD (Stuttgart/Dresden) basis set for the metal atoms. The compounds were tested for antimicrobial efficiency against Gram‐positive bacteria, Gram‐negative bacteria, and fungus strain. Finally, molecular docking was used to study the interactions between donors (the current compounds) and receptors FabH–CoA complex (PDB code: 1HNJ).

Biosynthesis of Naringenin@Cu (II), Zn (II) Hybrid Nanoflower: Anticancer Activity Assay process

In the study, the synthesis of organic-inorganic hybrid nanoflowers, which have a flower-like structure and are called nanoflowers, was carried out. For this purpose, hybrid nanoflower synthesis was carried out using naringenin as the organic part and different metal ions (Cu and Zn) as the inorganic part. Various analyzes were carried out to characterize the synthesized nanoflowers (such as SEM, EDX, FTIR, XRD). In addition, the anticancer activities of hybrid nanoflowers were tested on the MCF7 (breast cancer) cell line. It was concluded that there was a good increase in anticancer activity when naringenin was converted into hybrid nanoflower form. In particular, the anticancer activity of hybrid nanoflowers synthesized with Zn metal ion was quite excellent. This means that Zn hybrid nanoflowers may be a safer therapeutic alternative than others.

Highly effective and selective recovery of germanium from coal acid leaching solution by trihydroxyl functionalized titanium dioxide

In this study, a novel trihydroxyl functionalized titanium dioxide (TiO2-NH2-3OH) was successfully synthesized by the Schiff base reaction method. TiO2-NH2-3OH was characterized by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FT-IR), x-ray Photoelectron Spectroscopy (XPS), x-ray diffraction techniques (XRD), and further applied to recover germanium (Ge(IV)) from coal acid leaching solution. TiO2-NH2-3OH exhibited superior capture performance on Ge(IV) at a pH of 3, and the optimal TiO2-NH2-3OH dosages were 0.8 g L−1. The distribution coefficients of germanium for coexisting metal ions (Zn2+, Co2+, Mn2+, Ni2+ and Al3+) were all greater than 1, indicating that TiO2-NH2-3OH had good selective adsorption performance for Ge(IV) in complex solution environments. Compared with other kinetic models, pseudo-second-order model was more suitable to reveal the absorption of Ge(IV). Moreover, the experiment data were fitted better with Langmuir model at 298 K than the other isothermal models, and the maximum adsorption capacity was up to 72.94 mg g−1. Thermodynamic data suggesting that the capture of Ge(IV) on TiO2-NH2-3OH was a spontaneous endothermic process, increasing the temperature was beneficial for the adsorption reaction to proceed. TiO2-NH2-3OH with saturated adsorption still maintained a high removal rate of 80.55 % of Ge(IV) after five cycles, indicating good stability and recyclability of TiO2-NH2-3OH. XPS analysis indicated that the capture of germanium by TiO2-NH2-3OH may be due to the ion exchange interaction between -OH and Ge(OH)4 on the adsorbent surface. This work indicated that TiO2-NH2-3OH had great advantages and potential for the recovery of Ge(IV) from coal acid leaching solution.

Construction of −SO3H and Zn2+ dual active sites over silica aerogel for NH3 adsorption: Collaborative efficiency enhancement performance and mechanism

The inherently corrosive and explosive nature of ammonia presents significant environmental and health hazards, highlighting the critical challenge of developing high-efficiency adsorbents for its removal. In this study, a dual-active site-modified silica aerogel containing Brønsted acid (−SO3H) and metal ions (Zn2+) was synthesized using both sol–gel and physical deposition methods for ammonia adsorbent. The optimally modified 3SO3H@SA aerogel displayed an adsorption capacity of 2.38 mmol·g−1. The incorporation of nanosized Zn2+ active sites boosted this capacity to 5.14 mmol·g−1, making a 210 % enhancement over the unmodified aerogel. Kinetic and NH3-TPD analyses underscored the increasing importance of chemical adsorption with the rise in active site abundance. Quantum chemical simulations elucidated the molecular-level adsorption mechanism, corroborating experimental results. The synergy between metal ions and acidic functionalities in this dual-modified aerogel demonstrates its efficacy and potential in NH3 adsorption applications, offering convincing insights for the development of high-capacity ammonia adsorbents.

Insights Into the Mechanochemical Glass Formation of Zeolitic Imidazolate Frameworks.

Metal-organic framework (MOF) glasses, known for their potential in gas separation, optics, and solid-state electrolytes, benefit from the processability of their (supercooled) liquid state. Traditionally, MOF glasses are produced by heating MOF crystals to their melting point and then cooling the liquid MOF to room temperature under an inert atmosphere. While effective, this melt-quenching technique requires high energy due to the high temperatures involved. It also limits the scope of new material development by restricting the compositional range to only those combinations of metal ions and linkers that are highly thermally stable. An alternative, mechanical milling at room temperature, has demonstrated its capability to transform MOF crystals into amorphous phases. However, the specific conditions under which these amorphous phases exhibit glass-like behavior remain uncharted. In this study, we explore the mechanochemical amorphization and vitrification of a variety of zeolitic imidazolate frameworks (ZIFs) with diverse linkers and different metal ions (Zn2+, Co2+ and Cu2+) at room temperature. Our findings demonstrate that ZIFs capable of melting can be successfully converted into glasses through ball-milling. Remarkably, some non-meltable ZIFs can also be vitrified using the ball-milling technique, as highlighted by the preparation of the first Cu2+-based ZIF glass.

Targeted synthesis, structural elucidation, density functional theory, and molecular docking studies of transition metal(II)/(III) complexes of levofloxacin‐based Schiff base for promising their antioxidant and antibacterial applications

Levofloxacin and 4‐aminoantipyrine undergo a condensation process to synthesize a novel Schiff base ligand (L). Metal complexes containing Co(II), Cu(II), Cd(II), Mn(II), Zn(II), Cr(III), Ni(II), and Fe(III) metal ions are prepared using this Schiff base ligand. The new ligand and its complexes are characterized by elemental analyses, Fourier transform infrared, mass spectrometry, ultraviolet–visible, magnetic moment, 1H‐NMR, molar conductivity, and powder X‐ray diffraction, and further thermogravimetric analysis (TG, DTA) verifies their thermal stability. The metal to ligand ratio is 1:1, according to the analytical results. Spectroscopic methods reveal that metal complexes are expected to have an octahedral geometry and demonstrate a neutral tridentate ligand behavior. It also becomes apparent from the molar conductivity values that all metal complexes are electrolytic in nature except zinc(II) and cadmium(II) complexes which are non‐electrolytes. Moreover, the bioactivity of the compounds are investigated. The antibacterial activity is investigated in relation to various Gram‐positive and Gram‐negative bacteria. The results give good indication for higher activity of the prepared compounds than the standard antibiotic drug. Also, the antioxidant activity of the newly prepared ligand and its complexes has been investigated via 2,2‐diphenyl‐1‐picrylhydrazyle (DPPH) free radical scavenging assay. The findings show that Schiff base complexes exhibit good antioxidant activity. Finally, theoretical density functional theory using density functional theory/B3LYP method and molecular docking studies with two receptors of 3T88 and 3Q8U are calculated for the investigated compounds.

Preparation of transparent and flexible regenerated kenaf CNF composite films with curcumin-metal complex for food packaging applications

Cellulose nanofibers (CNF) derived from kenaf plant were combined with curcumin (Cur)-metal complexes to produce regenerated composite films. Cur was used to synthesize homoleptic Cur-metal complexes with diamagnetic Zn(II) and paramagnetic Cu(II) metal ions. Cur-Zn(II) complex and Cur-Cu(II) complex were synthesized under the same reaction conditions to check the synergistic effect of engaging the diketone electrons of Cur with strong coordination bonds with two different metal ions. The synthesized Cur-metal complexes were used as fillers to produce CNF composite films for biodegradable food packaging film. Results showed that the Cur-Zn(II) complex-loaded CNF composite films exhibit higher antioxidant activity than other films whereas Cur-Cu(II) complex-loaded CNF composite films showed prominent antibacterial activity against foodborne pathogenic bacteria such as Listera monocytogenes and Escherichia coli. It is due to the coordination of the diketone electron of Cur with diamagnetic and paramagnetic metal ions that influenced the antioxidant and antibacterial properties of Cur. Overall, this study proved that it was possible to use Cur in the form of Cur-Zn(II) complex as an antioxidant filler and Cur-Cu(II) complex as an antibacterial filler for active food packaging applications.

Green Fluorescence Property of Chromone-based Hydrazone Towards Zn2+ Ion

Excessive concentration of Zn in the environment may lead to bad toxicological responses that can affect human health and create numerous challenges in the environment. Therefore, it is very important to develop a sensitive method such as selective chemosensors based on fluorescence property which does not require laborious work in order to detect Zn metal ion. A formylchromone-thiosemicarbazide with two chloro derivatives namely DFCTSC was synthesized from reflux reaction of 6,8-dichloroformylchromone (DCF) and thiosemicarbazide (TSC) in ethanol. The characterisation of ligand structure was determined by using spectroscopic techniques such as Fourier transform infrared spectroscopy (FT-IR), ultraviolet-visible spectroscopy (UV-VIS) and nuclear magnetic resonance spectroscopy (NMR). Meanwhile, the fluorescence property of DFCTSC in the presence of Zn ion was recorded using fluorescence spectrophotometer. The result showed DFCTSC has a good fluorescence behaviour towards Zn ion by giving turn-on green fluorescence at peak 500 nm and emit light when it observed under UV light. The behaviour displayed the ability of ligand to be used as a potential fluorescent chemosensor for detecting Zn2+.

Sequential assembly enhanced selectivity on magnetic imprinted polymers for specific capture of naringin: A combination of synergistic dual sites and imprinted effect

Green and sustainable recovery of high-value natural flavonoids in agricultural wastes could not only improve natural resource utilization, but also could effectively reduce environmental pollution. Recently, great efforts have been made for research on the development of magnetic imprinted composite adsorbent, but the simultaneous promotion of stable selectivity and high adsorption amounts still faces its challenges. Inspired by “Sandwich-like” transport channels with proper steric and specific affinity sites, herein we designed a new kind of surface-imprinted magnetic colloidal nanocrystal clusters (MCNCs) with dual recognition sites (MCNCs@DR-MIPs) via sequential surface imprinted strategy. A two-step sequential surface-initiated atom transfer radical polymerization (SI-ATRP) was employed to construct the double imprinted sites, which can significantly improve the adsorption selectivity and adsorption amounts. In this design, the metal ion Zn(II) and the low pKa boronic acid APBA (1-allylpyridine-3-boronic acid, pKa = 7.4) could effectively tune the appropriate yolk-shell confinement sites, the obtained artificial double imprinted binding sites establishes the promising chemical environment for selective separation. As expected, the adsorption equilibrium experiments exhibited adsorption kinetics (180 min) and the maximum equilibrium binding capacity (34.60 µmol g−1). In virtue of unique advantages of magnetic separation materials, this novel absorbent exhibited a green and environmentally friendly enrichment process for naringin (NRG). Meanwhile, MCNCs@DR-MIPs showed excellent selectivity (imprinted factor 2.15) and regeneration properties (only decreased by 8.22 % after 7 cycles) for NRG. Additionally, the commercially available NRG could be effectively extracted and concentrated to 94.78 %. This study offers a sustainable effective strategy for flavonoids purification of magnetic separation materials and promotes advance the other natural compounds from agricultural wastes.

Solvent‐Free Oxidation of Benzyl Alcohol Using Modified Zeolitic Imidazolate Frameworks‐8 (ZIF‐8) Catalysts

AbstractSelective oxidation of alcohols towards carbonyl‐based products, such as aldehydes, is a subject of significant interest in the field of catalysis. Herein, a Zn‐based MOF with 2‐methylimidazolate linker (ZIF‐8) is modified and introduced as catalysts in a selective oxidation of alcohol with benzyl alcohol as the model of the reaction. Modification of ZIF‐8 includes the inclusion of Co(II), Cu(II) or Ni(II) ions as partial replacements for the original Zn(II) metal ions during the synthesis process. The resulting modified ZIF‐8 displays similar PXRD patterns to that of ZIF‐8, indicating no alteration of structures after the introduction of Co(II), Cu(II) or Ni(II) ions. However, the addition of Co(II) was found to modify the resulting ZIF‐8 composition to a higher extent compared to that of Cu(II) and Ni(II) ions. The catalytic test of benzyl alcohol oxidation was performed in a solvent‐free condition with TBHP as the oxidant. Reaction optimization includes reaction temperature, mass of catalysts, TBHP concentration, and reaction time. Among all the catalysts employed in the oxidation of benzyl alcohol, Co(II)‐ and Cu(II)‐modified ZIF‐8 show the highest catalytic activity with 64 % and 62 % conversion, respectively. Furthermore, the catalyst leaching and recyclability tests show that the reactions proceed in heterogeneous systems.

Enhancing nanoplastics removal by metal ion-catalyzed ozonation

Nanoplastics (NPs), characterized by sizes < 1 µm, are not completely removed in conventional drinking water treatment plants affecting human health. Catalytic ozonation appears as a promising alternative due to its ability to oxidize emerging pollutants by generating hydroxyl radicals with higher removal rate and mineralization than single ozonation. In this work, catalytic ozonation was investigated for the removal of polystyrene nanoplastics (PSNPs) by employing transition metal ion catalysts, Fe3+, Co2+, Ni2+, and Zn2+. The single ozonation of PSNPs, in the absence of catalyst, led to low turbidity reduction (33 %) and low mineralization rate (16 %) even after 2 h reaction time. Nevertheless, the rapid size reduction of PSNPs by >99 % in less than 5 min of ozonation (TOD: 30 mg L−1) was confirmed. This fact could imply a new issue under the ozone disinfection conditions by the formation of smaller-size particles. However, in the presence of Co2+ (1 mM), the highest PSNPs ozonation performance was achieved, decreasing the turbidity up to 65 % and achieving 70 % of mineralization in the same ozonation time. The scavenger experiments with methanol confirmed that direct ozonation and catalyst role were responsible for PSNPs degradation, with the generation of •OH being the most dominant catalytic mechanism. Therefore, although single ozonation at disinfection doses reduced the particle size of PSNPs, the catalytic process demonstrated greater efficacy in the total removal of PSNPs. These results highlight the need to further investigate ozonation of NPs intermediates, and the synergic improvements of catalytic ozonation for their mineralization.

Aspect on IR and TGA studies on the effect of some complexes solvents prepared by reactions of Arginine with metal ions of Zn(II),Cr(III),Co(II) and Fe(III)

Aspect on IR and TGA studies on the effect of some complexes solvents prepared by reactions of Arginine with metal ions of Zn(II),Cr(III),Co(II) and Fe(III)