Chelating Interaction Research Articles

A Divalent Metal Cation-Metabolite Interaction Model Reveals Cation Buffering and Speciation.

I present the perspective that the divalent metalome and the metabolome can be modeled as a network of chelating interactions instead of separate entities. I review progress in understanding the complex cellular environment, in particular recent contributions to modeling metabolite-Mg2+ interactions. I then demonstrate a simple extension of these strategies based approximately on intracellular Escherichia coli concentrations. This model is composed of four divalent metal cations with a range of cellular concentrations and physical properties (Mg2+, Ca2+, Mn2+, and Zn2+), eight representative metabolites, and interaction constants. I applied this model to predict the speciation of divalent metal cations between free and metabolite-chelated species. This approach reveals potentially beneficial properties, including maintenance of free divalent metal cations at biologically relevant concentrations, buffering of free divalent metal cations, and enrichment of functional metabolite-chelated species. While currently limited by available interaction coefficients, this modeling strategy can be generalized to more complex systems. In summary, biochemists should consider the potential of cellular metabolites to form chelating interactions with divalent metal cations.

Amino-modified microporous hyper-crosslinked resins for heavy metal ions adsorption

In this work, a high surface area micro/mesoporous hyper-crosslinked resin based on vinylbenzyl chloride and divinylbenzene is synthesized through a solvent-free polymerization followed by Friedel-Crafts alkylation. The hyper-crosslinked resin is then functionalized with amino moieties and the effect of the functionalization on the adsorption of metal ions is evaluated. After a chemical-physical characterization of the hyper-crosslinked resins, equilibrium adsorption tests of Pb(II) and Cu(II) in water are performed. The plain and amino-modified hyper-crosslinked resins (HCLR and HCLR-NH2) exhibit specific surface area (SSA) of about 1800 m2/g and 800 m2/g, respectively. They both exhibit micro/mesoporous structure, and their pore size distribution is modified upon functionalization. The amino-functionalization, while reducing prevalently the mesoporosity of the resin, does not significantly affect the micropores. HCLR-NH2 displays higher efficiency in removing both metal ions from aqueous solution compared to the unmodified resin. HCLR-NH2 is able to capture up to about 70 % of Pb(II) and up to about 48 % of Cu(II) dissolved in water at 5 mg/L concentration while in the same tests, HCLR captures about 25 % of Pb(II) and 17 % of Cu(II). The resins adsorption mechanisms follow the Langmuir model, suggesting a specific and functional groups-related adsorption mechanism. Therefore, the major adsorption capacity of HCLR-NH2 is to be primary attributed to the grafted amino moieties, which establish chelating interactions with the metal cations. Overall, results assess the relevance of the micropores and the amino functionalization to capture Pb and Cu ions via adsorption.

Efficient enrichment of uranium (VI) in aqueous solution using magnesium–aluminum layered double hydroxide composite phosphate-modified hydrothermal biochar: Mechanism and adsorption

This study presents the successful synthesis of Magnesium-aluminum layered double hydroxide composite phosphate-modified hydrothermal biochar for efficient removal of U(VI) from aqueous solutions. A novel synthesis approach involving phosphate thermal polymerization-hydrothermal method was employed, deviating from conventional pyrolysis methods, to produce hydrothermal biochar. The combination of solvent thermal polymerization technique with hydrothermal process facilitated efficient loading of layered double hydroxide (LDH) components onto the biochar surface, ensuring simplicity, low energy consumption and enhanced modifiability. Bamboo waste was utilized as the precursor for biochar, highlighting its superior green and sustainable characteristics. Additionally, this study elucidated the interactions between phosphate-modified hydrothermal biochar and LDH components with U(VI). Physicochemical analysis demonstrated that the composite biochar possessed a high surface area and abundant oxygen-containing functional groups. XPS and FTIR analyses confirmed the efficient adsorption of U(VI), attributed to chelation interactions between phosphate groups, magnesium hydroxyl groups, hydroxyl groups and U(VI), as well as the co-precipitation of U(VI) with multi-hydroxyl aluminum cations captured by LDH. The composite biochar reached adsorption equilibrium with U(VI) within 80 min and exhibited excellent fitting to the pseudo-second-order kinetic model and Langmuir model. Under conditions of pH = 4 and 298 K, it displayed significantly high maximum adsorption capacity of approximately 388.81 mg g⁻1, surpassing untreated biochar by 17-fold. The adsorption process was found to be endothermic and spontaneous and even after five consecutive adsorption-desorption cycles, the removal efficiency of U(VI) remained stable at 75.46%. These findings underscore the promising application prospects of Magnesium-aluminum layered double hydroxide composite phosphate-modified hydrothermal biochar in efficiently separating U(VI) from uranium-containing wastewater, emphasizing its environmental and economic value.

New insights into the interfacial characteristics of Poly(Acrylic Acid) binder and hydrated V2O5 cathode material for zinc-ion secondary batteries

Hydrated vanadium pentoxide and poly(acrylic acid) (PAA) are employed as a cathode active material and a binder, respectively, for aqueous zinc-ion secondary batteries (AZIBs). This study investigates the physicochemical interfacial characteristics of the PAA binder, with a particular focus on the intermolecular interactions between the binder and the hydrated V2O5 cathode materials. The PAA binder enables rapid Zn2+ diffusion by providing ion diffusion pathways, thereby enhancing the kinetics of the V2O5 cathode. The PAA binder improves hardness and ion conductivity while reducing the modulus, which results in AZIBs with stable cycle performance under our experimental conditions. The significantly enhanced electrochemical performance is attributed to the strong hydrogen bond and chelation interactions between the PAA and the surface of the hydrated V2O5 cathode materials. Thus, a Zn–V2O5 battery employing a PAA binder outperformed existing AZIBs, showing an impressive capacity of 504.5 mAh g−1 at 0.1 A g−1 and a robust cycling retention of 99.9 % over 1000 cycles, demonstrating the potential of aqueous binders in vanadium-based cathode materials.

Selective biosorption and recovery of scandium using the alga Fucus vesiculosus

The goal of this work was to study the viability of the application of biosorption using the brown alga Fucus vesiculosus in the recovery of scandium from red mud. The highest affinity of the biosorbent for scandium and aluminium was at pH 3. Sorption isotherms fitted to the Langmuir model for scandium and aluminium with adsorption capacities as high as 1.04 mmol·g−1 for both metals but with higher affinity for scandium than for aluminium. The performance of the biomass in fixed-bed columns was evaluated in different experimental conditions (flow rate, bed height and inlet metal concentration). Metal desorption was achieved with different inorganic and organic acids. After three consecutive sorption–desorption cycles using 0.1 N citric acid and deionized water during the regeneration step, the brown alga showed a progressive increase in scandium uptake due to the cross-linking citric acid and the alginate chains. The biomass was characterized before and after biosorption using Fourier transforms infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) coupled with an energy dispersive elemental analyser (EDS). The sorption involves different functional groups, such carboxylate and sulphonic groups by chelation and electrostatic interactions.

Efficient capture performance and mechanism of thiadiazole-functionalized covalent organic framework for Pb(II) ion

Covalent organic frameworks (COFs) are very promising adsorbent developed during recent years. Here, a COFs adsorbent (COF@HPLC) for efficient adsorption of lead is designed by post-modification. The adsorption properties were studied by batch adsorption. It is shown that pH 4 is the optimum value for the adsorption of Pb(II) by COF@HPLC. When the temperature is 25 °C, the maximum adsorption capacity of COF@HPLC reaches 251.37 mg/g. The fitting results of adsorption isotherm indicate that the process is a non-uniform adsorption in a single molecular layer. The activation energy fitted by the Dubinin-Radushkevich model are 16.22 kJ/mol, 21.32 kJ/mol, 18.87 kJ/mol and 16.67 kJ/mol, showing that Pb(II) adsorption by COF@HPLC is a chemical reaction. Kinetic studies show also that Pb(II) adsorption is a chemically controlled process. Thermodynamic shows that the adsorption is a spontaneously exothermic process. Finally, COF@HPLC has good adsorption selectivity and reusability. The adsorption mechanism of Pb(II) by COF@HPLC was the electrostatic and chelating interaction between functional groups containing sulphide and nitrogen and Pb(II) based on the zeta potential, XPS and DFT analyses. This work offers guidance toward the design and preparation of functional adsorbents for the treatment and removal of Pb(II).

Modelling and optimising the performance of graphene oxide-Cu2SnS3-polyaniline nanocomposite as an adsorbent for mercury ion removal.

Finding a cost-effective, efficient, and environmentally friendly technique for the removal of mercury ion (Hg2+) in water and wastewater can be a challenging task. This paper presents a novel and efficient adsorbent known as the graphene oxide-Cu2SnS3-polyaniline (GO-CTS-PANI) nanocomposite, which was synthesised and utilised to eliminate Hg2+ from water samples. The soft-soft interaction between Hg2+ and sulphur atoms besides chelating interaction between -N and Hg2+ is the main mechanism for Hg2+ adsorption onto the GO-CTS-PANI adsorbent. Various characterisation techniques, including Fourier transform infrared spectrophotometry (FT-IR), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), elemental mapping analysis, and X-ray diffraction analysis (XRD), were employed to analyse the adsorbent. The Box-Behnken method, utilising Design Expert Version 7.0.0, was employed to optimise the crucial factors influencing the adsorption process, such as pH, adsorbent quantity, and contact time. The results indicated that the most efficient adsorption occurred at pH 6.5, with 12mg of GO-CTS-PANI adsorbent, and 30-min contact time that results in a maximum removal rate of 95% for 50mg/L Hg2+ ions. The study also investigated the isotherm and kinetics of the adsorption process that the adsorption of Hg2+ onto the adsorbent happened in sequential layers (Freundlich isotherm) and followed by the pseudo-second-order kinetic model. Furthermore, response surface methodology (RSM) analysis indicates that pH is the most influential parameter in enhancing adsorption efficiency. In addition to traditional models, this study employed some artificial intelligence (AI) methods including the Random Forest algorithm to enhance the prediction of adsorption process efficiency. The findings demonstrated that the Random Forest algorithm exhibited high accuracy with a correlation coefficient of 0.98 between actual and predicted adsorption rates. This study highlights the potential of the GO-CTS-PANI nanocomposite for effectively removing of Hg2+ ions from water resources.

Extraction and characterization of anthocyanin pigments from Iris flowers and metal complex formation

Exploring the chemical processes and factors influencing the stability of the blue color derived from anthocyanins is a crucial objective in agricultural and food chemistry research. The ability of these compounds to bind with metals could potentially stabilize anthocyanins extracted from plant-based foods or enable modifying their hues for application as natural food colorants. This study had two core objectives - first, to extract and identify the major anthocyanin pigments responsible for iris flower coloration. Second, to selectively complex purified iris anthocyanins with aluminum (Al3+) and copper (Cu2+) ions, probing the coordination chemistry underlying synthetic metalloanthocyanin formation. Fresh iris flowers were collected and anthocyanins extracted using an optimized acidic solution. After separation, anthocyanins were complexed with metals Al3+ and Cu2+ at pH 5–6 to understand better the evolution of blue and green colors in anthocyanin-metal chelates. Characterization of anthocyanins and their metal complexes utilized UV–visible spectrometry, colorimetry (L\\* a\\*b\\* values), FTIR spectroscopy, and LC-MS. Metal complexation of anthocyanins exhibited bathochromic shifts of visible absorption maxima from 538 to 584 nm for Al-complex and 538–700 nm for Cu-complex. Color changes were accompanied by decreased lightness (L\\*, from 87 to 81) and color coefficients a\\* (+5.4 to −6.8) and b\\* (−12.2 to −4.8). LC-MS analysis identified five major anthocyanin aglycones: cyanidin (Cyd, m/z 289), delphinidin (Dpd, m/z 305), petunidin (Ptd, m/z 229), malvidin (Mv, m/z 329) and pelargonidin (m/z 273), along with various glycosylated derivatives. This work successfully isolated key iris anthocyanin pigments and elucidated their metal chelation interactions underlying expanded floral color production, bridging knowledge gaps about this underexplored genus.

Highly Selective Pb(II) Adsorption by DTPA-Functionalized Graphene Oxide/Carboxymethyl Cellulose Aerogel.

Graphene oxide (GO) exhibits a strong adsorption capacity for the removal of heavy metal ions from liquids, making it a topic of increasing interest among researchers. However, a significant challenge persists in the preparation of graphene oxide-based adsorbents that possess both high structural stability and excellent adsorption capacity. In this paper, a green and environmentally friendly ternary composite aerogel based on graphene was successfully synthesized. The adsorption capacity of graphene oxide was enhanced through diethylenetriaminepentaacetic acid modification, while the incorporation of composite carboxymethyl cellulose improved the structural stability of the composite aerogel in liquid. The composite aerogel demonstrates robust interactions between its components and features a multiscale porous structure. Adsorption tests conducted with Pb(II) revealed that the GO/DTPA/CMC (GDC) composite aerogel exhibits a favorable adsorption capacity. The study of adsorption kinetics and isotherms indicated that the adsorption process follows the quasi-secondary adsorption model and Freundlich adsorption model, suggesting a chemical multilayer adsorption mechanism, and the maximum adsorption capacity for Pb(II) ions was 521.917 mg/g based on the quasi-quadratic kinetic model fitting. X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) analyses, performed before and after adsorption, confirmed that the adsorption of Pb(II) primarily occurs through chelation, complexation, proton exchange, and electrostatic interactions between ions and active sites such as hydroxyl and carboxyl groups. This study presents an innovative strategy for simultaneously enhancing the adsorption properties of graphene oxide-based composite aerogels and ensuring solution stability.

Electrospun Fiber Membrane with the Dual Affinity of Chelation and Covalent Interactions for the Efficient Enrichment of Glycoproteins.

As important biomarkers of many diseases, glycoproteins are of great significance to biomedical science. It is essential to develop efficient glycoprotein enrichment platforms and investigate their adsorption mechanism. In this work, a conspicuous enrichment strategy for glycoproteins was developed by using an electrospun fiber membrane wrapped with polydopamine (PDA) and modified with 3-aminophenylboronic acid and nickel ions, named PAN/DA@PDA@APBA/Ni. The enrichment characteristics of PAN/DA@PDA@APBA/Ni toward glycoproteins were explored through adsorption behavior. Thanks to the existence of two sites of interaction (metal ion chelation and boronate affinity), PAN/DA@PDA@APBA/Ni exhibited significant enrichment capacity for glycoproteins, ovalbumin (604.6 mg/g), and human immunoglobulin G (331.0 mg/g). The adsorption kinetic results of glycoprotein ovalbumin on PAN/DA@PDA@APBA/Ni conform to the pseudo-first-order kinetic model in the first adsorption stage, while the second half adsorption stage is more in line with the pseudo-second-order kinetic model. Moreover, the physical characteristics of PAN/DA@PDA@APBA/Ni and subsequent adsorption experiments on electrospun fiber modified with only phenylboronic acid or nickel ions both confirmed two sites of interaction (metal ion chelation and boronate affinity, respectively). Furthermore, a stepwise elution method with dual-affinity interaction was designed and successfully applied to enrich glycoproteins in real biological samples. This work provides an idea for sample pretreatment, especially for the design of dual-affinity materials in glycoproteins enrichment.

Polyamidoamine dendrimers modified MXene and its high-performance adsorption behavior for Cr(VI)

Heavy metal pollution of water is a worldwide problem. The enticing characteristics exhibited by transition metal carbides (MXene) render it a good choiceas an adsorbent for removal of water pollutants. However, the limited functional group diversity and number, as well as the inadequate stability of MXene, impose limitations on its suitability for the adsorption of specific target metal ions (e.g., Hexavalent Cr(VI)). Herein, polyamidoamine (PAMAM) dendrimers, namely hyperbranched surfactant polymers, are employed to modify MXene, enhancing its surface functional group diversity and number. The presence of abundant –NH2 groups on the surface of PAMAM-modified MXene greatly enhances the adsorption capacity for Cr(VI). The pseudo-second order kinetic model and Langmuir isotherm model are suitable for describing the adsorption process. According to the Langmuir isotherm model, the maximum adsorption capacity (qm) can reach approximately 318 mg·g−1. Additionally, this adsorbent also has an excellent adsorption selectability for Cr(VI) from coexistent cations solution. Through the mechanisms of electrostatic attraction, reduction, covalent bonds, and chelation interaction, the high-performance adsorption for Cr(VI) can be achieved. Notably, the presence of PAMAM polymer as a protector ensures good stability of the composite adsorbent throughout adsorption/desorption cycle. This work provides deep insights into the advancement of highly efficient MXene-based adsorbents for water purification applications.

Discovery of Tetrazolamide-benzimidazol-2-ones as Novel 4-Hydroxyphenylpyruvate Dioxygenase Inhibitors.

4-Hydroxyphenylpyruvate dioxygenase (HPPD, EC 1.13.11.27) is one of the most valuable herbicide targets due to its unique biological functions. In search of HPPD inhibitors with promising biological performance, we designed and synthesized a series of novel tetrazolamide-benzimidazol-2-ones using a structure-based drug design strategy. Among the synthesized compounds, 1-(2-chlorobenzyl)-3-methyl-N-(1-methyl-1H-tetrazol-5-yl)-2-oxo-2,3-dihydro-1H-benzo[d]imidazole-4-carboxamide, 25, IC50 = 10 nM, was identified to be the most outstanding HPPD inhibitor, which showed more than 36-fold increased Arabidopsis thaliana HPPD (AtHPPD) inhibition potency than mesotrione (IC50 = 363 nM). Our AtHPPD-25 complex indicated that one nitrogen atom on the tetrazole ring and the oxygen atom on the amide group formed a classical bidentate chelation interaction with the metal ion, the benzimidazol-2-one ring created a tight π-π stacking interaction with Phe381 and Phe424, and some hydrophobic interactions were also found between the ortho-Cl-benzyl group and surrounding residues. Compound 32 showed more than 80% inhibition against all four tested weeds at 150 g ai/ha by the postemergence application. Our results indicated that the tetrazolamide-benzimidazol-2-one scaffold may be a new lead structure for herbicide discovery.

Modifying Surface Termination by Bidentate Chelating Strategy Enables 13.77% Efficient Kesterite Solar Cells.

Surfaces display discontinuities in the kesterite-based polycrystalline films can produce large defect densities, including strained and dangling bonds. These physical defects tend to introduce electronic defects and surface states, which can greatly promote nonradiative recombination of electron-hole pairs and damage device performance. Here, an effective chelation strategy is reported to suppress these harmful physical defects related to unterminated Cu, Zn, and Sn sites by modifying the surface of Cu2ZnSn(S,Se)4 (CZTSSe) films with sodium diethyldithiocarbamate (NaDDTC). The conjoint theoretical calculations and experimental results reveal that the NaDDTC molecules can be coordinate to surface metal sites of CZTSSe films via robust bidentate chelating interactions, effectively reducing surface undercoordinated defects and passivating the electron trap states. Consequently, the solar cell efficiency of the NaDDTC-treated device is increased to as high as 13.77% under 100mW cm-2 illumination, with significant improvement in fill factor and open-circuit voltage. This surface chelation strategy provides strong surface termination and defect passivation for further development and application of kesterite-based photovoltaics.

A copper-loaded self-assembled nanoparticle for disturbing the tumor redox balance and triple anti-tumor therapy.

Both chemodynamic therapy and photodynamic therapy, based on the production of reactive oxygen (ROS), have excellent potential in cancer therapy. However, the abnormal redox homeostasis in tumor cells, especially the overexpressed glutathione (GSH) could scavenge ROS and reduce the anti-tumor efficiency. Therefore, it is essential to develop a simple and effective tumor-specific drug delivery system for modulating the tumor microenvironment (TME) and achieving synergistic therapy at the tumor site. In this study, self-assembled nanoparticles (named CDZP NPs) were developed using copper ion (Cu2+), doxorubicin (Dox), zinc phthalocyanine (ZnPc) and a trace amount of poly(2-(di-methylamino)ethylmethacrylate)-poly[(R)-3-hydroxybutyrate]-poly(2-(dimethylamino)ethylmethacrylate) (PDMAEMA-PHB-PDMAEMA) through chelation, π-π stacking and hydrophobic interaction. These triple factor-responsive (pH, laser and GSH) nanoparticles demonstrated unique advantages through the synergistic effect. Highly controllable drug release ensured its effectiveness at the tumor site, Dox-induced chemotherapy and ZnPc-mediated fluorescence (FL) imaging exhibited the distribution of nanoparticles. Meanwhile, Cu2+-mediated GSH-consumption not only reduced the intracellular ROS elimination but also produced Cu+ to catalyze hydrogen peroxide (H2O2) and generated hydroxyl radicals (˙OH), thereby enhancing the chemodynamic and photodynamic therapy. Herein, this study provides a green and relatively simple method for preparing multifunctional nanoparticles that can effectively modulate the TME and improve synergetic cancer therapy.

An insight into fine cassiterite recovery: A novel surfactant-phenylpropylhydroxamic acid and its adsorption mechanism

The effective recovery of fine-grained cassiterite is a difficult problem in tin ore beneficiation. For enhancing the performance of the traditional collector for fine cassiterite flotation, a novel surfactant phenyl propyl hydroxamic acid (PHA) was designed by introducing one ethyl group (–CH2-CH2-) into benzohydroxamic acid (BHA).The study of flotation properties and the adsorption mechanism of PHA onto cassiterite surface were systematically investigated by scanning electron microscopy-energy dispersive X-ray spectroscopy testing (SEM-EDS), adsorption measurements, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and Density functional theory (DFT). The results indicate that PHA has an excellent flotation performance for fine cassiterite compared with BHA and salicylhydroxamic acid (SHA), and the interaction between PHA and the surface of mineral mainly exhibited chemisorption attributed to new Sn-O chemical bonds. Meanwhile, DFT calculations showed that PHA adsorbed on the cassiterite surface via chelating interaction by the formation of a five-membered chelate ring.

A double cross-linked anisotropic quaternized chitosan/sodium alginate-based wound dressing for rapid drainage of biofluids

Excessive biofluid around wounds can cause infection and prevent healing. In this study, an anisotropic quaternized chitosan (QC)/sodium alginate (AL)-based aerogel wound dressing was prepared via a directional freeze-drying technique inspired by the channel structure used for water transport in trees. The aligned channels provided the dressing with self-pumping ability, allowing it to rapidly and completely remove biofluids and absorb biofluids up to 1292.5 % of its own weight. To enhance the strength of the dressing, a double cross-linked network was constructed based on the QC-AL electrostatic attraction and AL-Ca2+ chelation interaction. The axial compressive strength of the double cross-linked dressing reached 207.3 kPa (ε = 50 %). In addition, the dressing exhibited strong conductive properties (conductivity = 13.0 S/m), antioxidant activities [reactive oxygen species (ROS) scavenging ability = 88.0 %], and hemostatic characteristics (blood coagulation index = 1.8 %). The dressing also exhibited powerful antibacterial performance, exhibiting over 98.0 % inhibition of E. coli and S. aureus. Experiments on diabetic mouse models revealed that the dressing considerably promoted wound healing. On day 3, the wound healing rate was 96.7 % faster in the QAC group than in the gauze group. Therefore, the developed dressing may have great potential for chronic wound care.

Study on the poly(methyl methacrylate-acrylic acid)/calcium phosphate cement composite bound by chelation with enhanced water absorption and biomechanical properties

Polymethylmethacrylate (PMMA) bone cement has been widely used as a critical material for fixing prostheses and filling bone defects. The shrinkage of PMMA bone cement was addressed by the additives, however, the uneven integral water absorption and expansion performance as well as the deteriorated mechanical properties of the modified bone cement after immersion in phosphate buffered saline (PBS) and simulation body fluid (SBF) affected the long-term stability after implantation. Calcium phosphate cement (CPC) is a biomaterial with promising applications in orthopedics, whose hydration reaction provides an important driving force for the transfer of water. Besides, the mechanical properties of CPC can be enhanced with the curing process. In this study, CPC was utilized to modify the poly(methyl methacrylate-acrylic acid) [P(MMA-AA)] bone cement. The results demonstrated the successful construction of interconnected CPC water delivery networks in the P(MMA-AA)/CPC composite, the water absorption ratio and expansion ratio of the composite were up to 131.18 ± 9.14% and 168.19 ± 5.44%, respectively. Meanwhile, the transformation of CPC water delivery networks into rigid mechanical support networks as well as the chelation interaction between organic-inorganic enhanced the mechanical properties of the composite after immersion, the compressive strength after immersion reached 62.97 ± 0.97 MPa, which was 27.65% higher than that before immersion. The degradation ratio of the composite was up to 13.76 ± 0.23% after 9 days of immersion, which was 16.4% higher than that of CPC. Furthermore, composites exhibited superior biocompatibility as the release of Ca2+. Therefore, P(MMA-AA)/CPC composite serves as a promising medical filling material for clinical use.

MOF-derived Co-Ni layered double hydroxides/polyethyleneimine modified chitosan micro-nanoreactor for high-efficiency capture of uranium from seawater

The preparation of powder adsorbent into microsphere adsorbent is one of the effective methods for the industrialization of uranium extraction from seawater. Herein, a MOF-derived Co-Ni layered double hydroxides/polyethyleneimine modified chitosan micro-nanoreactor (DNPM) was prepared by a simple method in this work. The microstructure and chemical structure of DNPM were comprehensively characterized. The pH value, adsorption time, initial solution concentration, temperature, competitive ions, regeneration performance, and bed column heights were investigated for the adsorption performance of DNPM by batch adsorption and fixed-bed column continuous adsorption experiments. When the contact time was 8 h, the initial concentration was 150 mg/L, and the pH value was 6, the adsorption capacity of DNPM was 334.67 mg/g. The uranium adsorption by DNPM fits with the pseudo-second-order kinetic and Langmuir models, which was a spontaneous and endothermic process. In addition, DNPM has good adsorption selectivity and reusability. The fixed-bed column continuous adsorption experiment shows that the adsorption capacity increased with the increase of bed column height. The adsorption mechanism can be attributed to coordination chelation and electrostatic interaction. In general, this work provides an effective strategy for developing environmentally friendly uranium adsorbent that can be industrially used.

Diatomite-Trichoderma viride composite microspheres for selective removal of anionic dyes and copper ions

Taking into account that Trichoderma viride dispersion mycelium existed many shortcomings, such as difficult to separate, easy to deactivate, and low adsorption performance, Diatomite-Trichoderma viride (DE-T. viride) composite microspheres were designed and prepared by chemical bonding, and anion dye and copper ion synergistic removal strategies were proposed. The adsorption performance of the composite microspheres on CR and Cu2+ were demonstrated by Zeta potential and Fourier infrared spectroscopy. The adsorption process followed the pseudo-second-order model, involving various mechanisms such as metal chelation, polysaccharide adhesion, hydrogen bonding, and electrostatic interactions. Intraparticle diffusion model identity that adsorption is controlled by multiple steps. Adsorption isotherms of CR and Cu2+ displayed excellent agreement with the Langmuir, Freundlich, and Temkin models. Impressively, DE-T. viride spheres exhibited maximum adsorption capacities of 176.3 and 63.8 mg/g for CR and Cu2+. Moreover, they displayed selective adsorption for anionic dyes, with capacities 8 and 10 times higher than those for cationic and neutral ionic dyes, respectively. T. viride microspheres generates extracellular polymers, which are rich in a variety of functional groups and can adsorb metal ions through chelation and transport, moreover, it adsorbs anions with positive charge. It is worth mentioning that DE-T. viride spheres exhibited ease of separation, stability, and reproducibility even after multiple adsorption-recycling cycles, maintaining an impressive adsorption rate of 80 %. In conclusion, these multifunctional, efficient, and eco-friendly DE-T. viride spheres present promising potential for environmental remediation, particularly in removing contaminants from various environmental matrices. Their outstanding performance, selectivity, and recyclability make them a valuable and sustainable solution for addressing pollution issues and promoting environmental sustainability.

Lewis base anchored DhaTph covalent-organic framework for effective capture of thorium(IV) ion

Capture of radioactive thorium (Th) ion from nuclear wastewater is highly necessary. However, current adsorbents show drawback in either adsorption capacity or adsorption rate. In this study, a DhaTph (Dha, 2,5-dihydroxyterephthalaldehyde; Tph, tetra-(p-aminophenyl)porphyrin) covalent-organic framework (COF) with Lewis base sites (C = N and –OH) was applied to capture Th(IV) ions from aqueous solution. DhaTph has a large (d, ∼2 nm) and transparent 1D channel, which makes the active Lewis bases interact with Th(IV) ion easily. Benefited from that, DhaTph exhibits a larger adsorption capacity of 525.0 mg g−1 and rapid adsorption speed (90 min for equilibrium) simultaneously. Besides, this COF owns superior adsorption for Th(IV) ion than various rare earth ions and some other common ions. The systematical characterization and theoretical calculation indicate that the strong chemical chelation interaction from C = N and –OH dominantly contributes to the effective capture of Th(IV) ion. Thus, our work indicates that DhaTph can serve as a potential adsorbent for selective capture of Th(IV) ion, and provides a guideline for designing effective COFs-based adsorbents. We expect this work will promote the application of highly stable COFs in the field of Th(IV) ion capture.