Molybdenum Ions Research Articles

Glutarimidedioxime: A Complexing, Reductive, and Nitrosyl Reagent for Molybdenum.

Glutarimidedioxime is a cyclic amidoxime moiety formed during the synthesis of amidoxime-functionalized fibers and apparently facilitates the extraction of uranium from seawater. Herein, we comprehensively explore differences between molybdenum and vanadium coordinated by glutarimidedioxime. The high adsorption of vanadium is explained by the formation of rare nonoxido vanadium(V) complexes, where each bare V5+ is coordinated with two tridentate glutarimidedioxime ligands. By contrast, molybdenum is coordinated by only one glutarimidedioxime ligand, and the oxido Mo═O bonds in molybdate cannot be displaced by the ligand. Under seawater conditions, vanadium is fully complexed. Meanwhile, approximately 25% of molybdenum ions are in the form of free molybdate even if the concentration of glutarimidedioxime is 100000 times that of molybdenum. Glutarimidedioxime was expected to be more stable in the presence of metal ions than without them. However, complexation with molybdenum accelerated the degradation of the glutarimidedioxime ligand to release hydroxylamine. Molybdenum(VI) was then reduced by hydroxylamine, which itself was oxidized into nitrosyl. Vanadium heavily outcompetes adsorption of uranium, while molybdenum causes the degradation of glutarimidedioxime; the latter issue has previously been neglected and was first reported here.

Synthesis of some anion exchange resins for selective separation of 99Mo and 131I: A comparative study

ABSTRACT Amination of styrene-divinylbenzene (SDVB) copolymers is a traditional process for preparing strong anion exchange resins that can greatly improve their performance and applications. In the present investigation, poly(styrene-co-divinyl benzene) copolymers functionalized by various amino groups were synthesized by the amination route. The performance of synthesized exchange resins for the separation and recovery of active Mo(VI) and I(I) isotopes from their aqueous solutions was compared to that of three commercial ion exchange resins, used in the actual production of these radioisotopes in the Radioisotopes Production Facility. The morphology and structural properties of the synthesized copolymers as well as the commercial reference resins were characterized using FT−IR, SEM, TG, and XPS. The results demonstrate that the copolymer was successfully functionalized with amino groups, where trimethylamine produced amination greater than triethylamine. Furthermore, the thermal stability of synthesized anion exchanges was significantly higher than that of commercial beads. The synthesized polymer networks presented excellent radiation stability under applied experimental conditions. Compared to the reference resins, the synthesized co-polymeric beads showed enhanced adsorption capability for MoO4 2− and I− ions from an aqueous solution. Further, the uptake affinity of the networks aminated with trimethylamine for both radioisotopes, in optimal conditions, was greater than that of triethylamine aminated beads. The sorption mechanism was inferred through FT−IR and XPS analysis, and the results clarified that the separation of both radioisotopes was substantially related to the amine functional groups on the resin framework. The spectroscopic analysis illustrated that one molybdenum ion (in the form of MoO4 2−) was subjected to an ion-exchange interaction and two Cl− ions in the amine resin. A similar exchange mechanism was predicted for I− with Cl− ions. Further, the enhanced sorption of Mo(VI) could be additionally attained through coordination interactions with N atoms in the amine groups that have good chelating capability toward metal ions. The reusability performance of the synthesized exchange resins is better than that of the commercial reference resins, where they could be effectively regenerated for up to five cycles. Finally, this study presents a new technique for the separation and recovery of Mo(VI) and I(I) from irradiated low-enriched U-targets by employing highly promising amino-modified polystyrene-divinyl benzene microspheres.

Mechanism of ion migration from the substrate material into snow cover at the end of the cold period

Earlier, it was established that maximum mineralization of the contact layer of snow occurs in spring at the interface with substrates (soil or ice). This study analyzes the temperature and moisture conditions during this period at the interface of the contact layer of snow with substrates by examining frozen sand blocks saturated with a solution containing complex gold ions, or blocks filled with polystyrene containing ions of molybdenum, copper, etc. It is assumed that the migration of ions from the underlying substrate into the contact layer of snow cover in spring occurs along quasi-liquid films on the surface of snow crystals, the thickness of which exceeds the equilibrium one. Migration becomes noticeable when the temperature at the snow–substrate contact reaches −13 °С and above. The appearance of quasi-liquid films on the surface of snow particles under variable temperature and moisture conditions is possible due to the condensation of water vapor, which during the day, with general heating of the system, can enter the contact layer of snow both from above and below. With an increase in snow density in the spring, the mineralization of the near-contact layer of snow cover increases. At the same time, linear relationships were revealed between the content of substrate components migrating into the near-contact layer of snow and the gradient of water vapor density in it. The reliability of the approximation of these dependencies for the gold thiosulfate complex is 0.98; for copper ions – 0.52; for hydrogen ions – 0.88; for sodium ions – 0.69, for chloride anions – 0.89. The results of the study substantiate the increased efficiency of geochemical prospecting for mineral deposits using snow cover in the spring.

Physical, optical, spectroscopic features of Li2B4O7-Bi2O3-Sb2O3 glass system reinforced with molybdenum ions

To comprehend the physical, optical and spectroscopic properties of a novel multicomponent glass system with compositional formula 60Li2B4O7-30Bi2O3-(10-x)Sb2O3-xMoO3 (x = 0, 2.5, 5, 7.5 and 10 mol%) has been synthesized by melt quench process. The lack of intense peaks in the XRD confirmed the glassy nature of the prepared samples. On Substitution of Sb2O3 with MoO3 in lithium tetraborate-bismuthate glasses, a linear decrease in the density and an increase in the molar volume has been noticed. Physical parameters like oxygen packing density, oxygen molar volume and packing density have been computed. Optical energy bandgap evaluated from UV–Visible absorption spectra, declined with increase of MoO3. Refractive indices exhibited opposite trend with optical energy bandgap and opens applications for non-linear optical devices. Vibrational modes in the as-prepared glasses have been identified by FTIR and Raman spectra. With increase in MoO3 content, Mo6+ ions transformed to Mo5+ units which in turn converted BO4 to BO3 units as confirmed by FTIR and Raman spectroscopies.

Preparation and Characterization of Pyramids/Particles NiO/SnO2 Composite for Sorption and Separation of Molybdenum and Zirconium Ions from Some Synthetic Fission Products

AbstractPyramids/particles of NiO/SnO2 composite (NS7) was produced by applying the sol–gel autocombustion method. The produced composite was investigated using different techniques, X-ray diffraction, Fourier-transform infrared, Raman spectroscopy, scanning electron microscope, dynamic light scattering, ultraviolet–visible absorbance spectroscopy, and BET surface area then was applied for the adsorption and separation of molybdenum and zirconium ions from lanthanum, strontium, and cesium. 3D pyramids of NiO and particles of SnO2 are confirmed in the composite with a homogeneous mesoporous structure. The composite has good affinity for zirconium and molybdenum ions with fast kinetics and Qmax of 27.1 and 33.3 mg/g, respectively, low affinity for lanthanum, and negligible affinity for strontium and cesium. The sorption mechanism is physical sorption and endothermic in nature. The adsorbed Zr(IV), Mo(VI), and La(III) ions were separated using the desorption process as the following sequence: First, 95 ± 2% (14.3 ppm) of the loaded La was desorbed by washing with double distilled water. Then 96 ± 2% (41.3 ppm) of the loaded Zr was recovered by 1 M potassium chloride without interfering ions. Finally, 98 ± 2% (42.88 ppm) of Mo is desorbed by 1 M sodium acetate solution. The NS7 composite can be reused five times successfully.

Phytochemical, biological, and computational investigations of Ephedra alata Decne. growing in salinity conditions of Arabian Peninsula

Ephedra alata Decne is a medicinal plant widely used in traditional medicine for the management of bronchial asthma and cancer. Phytochemical analysis and biological activities, including antioxidant and anticancer effects, were investigated in the current work as new findings for the plant E. alata, a species growing wildly in the marsh and saline environments of the central area of Saudi Arabia. The Ultra Pressure Liquid Chromatography coupled with Electron spray ionization-Quadropole-Time of flight (UPLC-ESI-Q-TOF) system was used for the phytochemical analysis of the plant constituents. In addition, Polyphenolic profiling including the total phenolic (TPC) and flavonoid (TFC) contents of the plant extracts were measured. Phenolic acids were found at the highest relative percentages among all the identified compounds and were measured at 66.07 mg GAE (Gallic acid equivalent). The UPLC analysis of the E. alata extract indicated the presence of chlorogenic acid, syringic acid, caffeic acid, vanillic acid, rosmarinic acid, umbelliferone, isorhoifolin, and apigenin at the highest relative percentages. Mineral analysis indicated that the microelement content of E. alata was relatively low, except for magnesium (Mg). In vitro antioxidant assays revealed the ability of the plant to scavenge DPPH free radicals, reduced molybdenum ions, and ferrous at levels of 14.63, 19.97, and 27.78 mg Trolox equivalents, respectively. The extract induced transition metal chelation at 31.36 mg EDTA equivalents. The extract induced cytotoxic effects against MDA-231 and A549 cell lines at IC50 levels of 25.31 and 39.81 µg/mL, respectively. The plant extract inhibited the colonization and migration of cancer cells as part of its potential anticancer effects. In addition, major E. alata constituents like isorhoifolin, chlorogenic acid, apigenin, and rosmarinic acid exhibited the lowest binding energy to the CAIX enzyme at − 8.41, − 6.64, − 6.32, and − 6.26 kcal/mol, respectively, compared to the binding energy (− 7.72 kcal/mol) of the co-crystallized ligand (Y0R). The docking results further supported the selection of the CAIX enzyme as a standard predictive therapeutic target, since it exhibited significant binding interactions with the major constituents of the plant.

Dual‐mode sensing biopolymer membrane impregnated with molybdenum for ethylene detection and monitoring of fruits

AbstractIn this study, a dual‐mode sensing biopolymer membrane employing chitosan (CS), polyvinyl alcohol (PVA), and ammonium molybdate (AM) was developed for optical and electrochemical detection of ethylene. The biopolymer composite was characterized by X‐ray diffraction (XRD), Fourier transform infra‐red (FTIR), and scanning electron microscopy (SEM).The relationship between ethylene concentration and optical/electrochemical response was investigated. XRD analysis showed enhanced ionic conduction, supported by SEM images showing uniform pore distribution within the synthesized membrane, facilitating effective gas interaction with Molybdenum. The increased FTIR peak intensities with higher amount of molybdenum in the membrane indicates enhanced molecular interactions. Applied to a microelectrode chip, the membrane exhibits a measurable electrochemical response with oxidation peak appearing in cyclic voltammogram as Molybdenum ions undergo reduction upon ethylene exposure. Colorimetric measurements, based on CIELAB values, reveals visible color shift with increasing ethylene concentrations, particularly at 10% molybdenum impregnation. Ionic conductivity and total color difference exhibit parallel variation with ethylene concentrations. X‐ray photoelectron spectroscopy confirms molybdenum oxidation state shift from +6 to +5 in the membrane upon ethylene interaction. The inexpensive colorimetric method enables direct color change visualization in practical applications. The resulting dual‐functional biopolymer membrane shows adaptability and versatility by responding to both optical and electrochemical signals.

Room-temperature mL-to-μL quantitative liquid concentration device for cyclone flow

Highly sensitive quantitative analysis of liquids is required in various fields. Analytical instruments and devices such as chromatography, spectroscopic analysis, DNA sequencers, immunoassay, mass spectrometry, and microfluidic devices are utilized for this purpose. Typically, the sample volume is at the milliliter scale, while the analysis volume is at the microliter scale. Consequently, most of the sample is discarded. Therefore, a universal volume interface is required to quantitatively concentrate samples from milliliter to microliter volume. This study introduces a liquid quantitative function to the cyclone concentration method using a millimeter-scale channel, which is highly suitable for controlling liquids at the microliter scale due to its high fluidic resistance against cyclone flow. This method enables the effective control of liquid concentration by cyclone flow. The optimum channel structure is investigated, and a 33-fold concentration of aqueous solutions is demonstrated. Finally, the concentration device is applied to measure molybdenum ions in a river.Graphical abstract

Enhanced corrosion resistance and electrical conductivity of stainless steel bipolar plates by molybdenum ion implantation

Enhanced corrosion resistance and electrical conductivity of stainless steel bipolar plates by molybdenum ion implantation

Gene sll1454 is important for growth of Synechocystis sp. PCC 6803 on nitrate as the only source of nitrogen

The gene sll1454 (narB) encodes a nitrate reductase in Synechocystis sp. PCC 6803. Deletion of sll1454 was performed by insertion of a gene coding for a neomycin phosphate transferase (npt) in both directions to the sll1454 ORF resulting in two different mutant strains named sll1454::npt direct and sll1454::npt complementary. Both strains lost the ability to grow on nitrate as the only source of nitrogen, but instead grew at the same rate as the wild type if ammonium was supplied. Trace metal replacement experiments revealed that tungsten ions inhibited the nitrate reductase in Synechocystis sp. PCC 6803, as no growth occurred with nitrate as the sole nitrogen source, if molybdenum ions were replaced equimolarly by tungsten ions. Vanadium ions, on the other hand, did not exert any negative effect under the same conditions and neither did the omission of molybdenum, tungsten or vanadium ions in the growth medium. The co-addition of molybdenum ions to cultures containing tungsten ions restored growth to the same rate as in cultures containing only molybdenum ions or none of them.Graphical abstract

Selective separation of rhenium from oxygen-pressure leach solution of molybdenite concentrate using modified D201 resin: Experiments and theoretical calculations

Recovering rhenium from highly acidic rhenium-containing leach solutions is challenging for most resins, particularly in multiplexed systems. Herein, we introduce a scheme for selectively obtaining rhenium from a multielement solution containing high concentrations of sulfuric acid using modified D201 resin. Considering the dosage of resin and parameters such as pH and adsorption temperature, the adsorption efficiencies under optimal conditions for rhenium, molybdenum, iron, and cerium were 97.46 %, 0.38 %, 0.94 %, and 1.10 %, respectively. The selective recovery mechanism of rhenium was investigated by fitting the experimental data to kinetic and adsorption isotherm models. The pseudo-second-order and Langmuir models better fit results corresponding to the experimental data, which indicates monolayer chemisorption of ReO4− formed on the resin surface. Meanwhile, various characterizations such as SEM-EDS, FTIR, XPS, etc., indicate that ReO4− initially combines with the protonated −CHN+H2CH2Cl on the modified resin surface and then undergoes ion exchange reaction with doped Cl−. Furthermore, because of the diverse forms and similar properties of molybdenum and rhenium ions in acidic solutions, a theoretical model based on density functional theory was used to simulate the selective adsorption process in leach solution with a pH of 1.7. The simulation results demonstrate a highest occupied molecular orbital–lowest unoccupied molecular orbital energy gap, observed in the following order: ΔEMoO22+ = ΔEReO4− < ΔEMoO42− < ΔEMo7O246−, which implies that MoO22+ and ReO4− were most likely to transition from their ground states to excited states and react with the electron donor and acceptor groups, respectively. Compared with MoO42−, ReO4− is more likely to react with the electron acceptor group and provides the corresponding methods and a theoretical reference for selective separation of rhenium in multielement solutions.

Multichannel Sensor for Detection of Molybdenum Ions Based on Nitrogen-Doped Carbon Quantum Dot Ensembles

Trace elements such as cobalt (Co), molybdenum (Mo), and zinc (Zn) play necessary roles in different biological functions. Co is a microelement that influences the vascular system. Mo works as an enzymatic cofactor of three enzymes (aldehyde oxidase, sulfite oxidase, and xanthine oxidase dehydrogenase). However, these elements are difficult to detect, since the analytical methods developed have a high cost, which restrict their applicability. In this sense, fluorescent sensors are an alternative for detecting trace elements, such as Mo4+ ions. Herein, a new multichannel trace elements sensor has been proposed to detect Mo entities. In this sense, two different N-CQDs were synthesized and fully characterized. The N-CQDs presented quantum yield values of 25.93% and 6.02% and excellent solubility in water. Also, a mixture of these two carbon-based nanoparticles was used to identify and to quantify Mo in water between seven different trace elements. The method was found to reach 1.28 and 3.88 ppm for limit of detection (LOD) and quantification (LOQ), respectively. To further verify the potential of the detection platform, the multichannel sensor was applied to identify the different concentrations of metal ions (Fe2+, Co2+, Mn2+, Cu2+, Zn2+, Mg2+, and Mo4+) in water. The data matrix was treated using different algorithms, such as K-Means and Discriminant Analysis (DA). The detection strategy has successfully identified the molybdenum ions at 5 ppm. This result shows the potential application of a multichannel sensor toward the detection of Mo entities, since it is comparable with the molybdenum test already available on the market.

Crosslinked Polydiallyldimethylammonium Chloride Adsorbent for the Selective Separation of Rhenium Ions from Pregnant Leach Solutions.

The depletion of valuable mineral reserves has rendered effluents generated from mining and industrial processing activities a promising resource for the production of precious elements. The synthesis and improvement of new adsorbents to extract valuable compounds from industrial wastes and pregnant leach solutions, besides increasing wealth, can play a significant role in reducing environmental concerns. In this work, a new and low-cost adsorbent for the selective extraction of rhenium (perrhenate ions, ReO4-) was synthesized by the free-radical polymerization (FRP) of a diallyl dimethylammonium chloride monomer (quaternary amine) in the presence of a crosslinker. Various methods were employed to characterize the polymeric adsorbent. The results revealed that the designed polymeric adsorbent had a high surface area and pores with nano-metric dimensions and a pore volume of 6.4 × 10-3 cm3/g. Four environments-single, binary, multicomponent, and real solutions-were applied to evaluate the adsorbent's performance in the selective separation of Re. Additionally, these environments were used to understand the behavior of molybdenum ions, the primary competitors of perrhenate ions in the ion exchange process. In competitive conditions, using variations in qe,mix/qe, an antagonism phenomenon (qe,mix/qe < 1) occurred due to the inhibitory effect of surface-adsorbed molybdenum ions on the binding of the perrhenate ions. However, across all conditions, the separation values for Re were higher than those for the other studied elements (Mo, Cu, Fe).

Electron impact broadening and atomic data for As IV-V, Mo V and In V spectral lines

Missing Stark broadening parameters for 33 spectral lines of several arsenic, molybdenum and indium ions (7 As IV, 4 As V, 12 Mo V and 10 In V lines) have been calculated using a quantum-mechanical method. All the considered spectral lines for As IV and As V have been detected for the first time in the atmospheres of cool DO white dwarfs HD 149499 B and p=HZ 21, these four As V lines that have been discovered in HD 149499 B are also present in the UV spectrum of hot white dwarf (WD) RE 0503−289. All the considered spectral lines for Mo V have been recently discovered for the first time in the ultraviolet (UV) spectrum of the DO-type white dwarf (WD) RE 0503−289. Also, the ten considered lines for In V have been detected in the ultraviolet (UV) spectrum of the DO-type white dwarf (WD) RE 0503−289, that five among those discovered — recently — for the first time. This recent discovery encourages us to calculate their Stark widths to fill the lack of the data base STARK-B and for use in investigations of observed spectra in such stars. Before the Stark widths evaluation, two calculation steps have been carried out : in the first step, we calculate the atomic structure and then the electron-ion collision as a second step using the sequence of the codes (superstructure, distorted wave, and jajom) of University College London. We provide our results for these lines at different temperature values and at density Ne=1017 cm−3.

Multidrug-Resistant Escherichia coli Remains Susceptible to Metal Ions and Graphene-Based Compounds.

Escherichia coli is listed as a priority 1 pathogen on the World Health Organization (WHO) priority pathogen list. For this list of pathogens, new antibiotics are urgently needed to control the emergence and spread of multidrug-resistant strains. This study assessed eighteen metal ions, graphene, and graphene oxide for their antimicrobial efficacy against E. coli in both planktonic and biofilm growth states and the potential synergy between metal ions and graphene-based compounds. Molybdenum and tin ions exhibited the greatest antimicrobial activity against the planktonic states of the isolates with minimal inhibitory concentrations (MIC) ranging between 13 mg/L and 15.6 mg/L. Graphene oxide had no antimicrobial effect against any of the isolates, while graphene showed a moderate effect against E. coli (MIC, 62.5 mg/L). Combinations of metal ions and graphene-based compounds including tin-graphene, tin-graphene oxide, gold-graphene, platinum-graphene, and platinum-graphene oxide exhibited a synergistic antimicrobial effect (FIC ≤ 0.5), inhibiting the planktonic and biofilm formation of the isolates regardless of their antibiotic-resistant profiles. The bactericidal effect of the metal ions and the synergistic effects when combined with graphene/graphene oxide against medically relevant pathogens demonstrated that the antimicrobial efficacy was increased. Hence, such agents may potentially be used in the production of novel antimicrobial/antiseptic agents.

Mesoporous molybdate-substituted hydroxyapatite nanopowders obtained via a hydrothermal route

In the last decade, mesoporous hydroxyapatite (HA) materials have received much attention regarding environmental applications (including adsorption of soil and water contaminants, films for lithium batteries, catalysts, and support systems for catalysis) and open up ample opportunities regarding biomedical devices and structures. Molybdenum ions may strongly influence catalytic and sorption properties of materials. The present study shows an influence of hydrothermal-synthesis conditions (including temperature and duration of the treatment) on phase composition, textural properties, and morphology of molybdate-containing HA. Powders with high crystallinity manifested Brunauer–Emmett–Teller specific surface area up to 55 m2/g with a pore volume of 0.33 cm3/g. The molybdate-containing HA powders were investigated by chemical analysis, X-ray diffraction, Fourier-transform IR spectroscopy, and transmission electron microscopy. Their specific surface area, pore volume, and pore size distributions were determined by low-temperature nitrogen adsorption measurements, zeta potential was quantified, and electron paramagnetic resonance spectroscopy was performed. The concentration of MoO42− preserving the one-phase state was found, and the impact of hydrothermal treatment mode was analyzed by machine learning using artificial neural networks.

Ion Implantation Combined with Heat Treatment Enables Excellent Conductivity and Corrosion Resistance of Stainless Steel Bipolar Plates for Hydrogen Fuel Cells.

316 L stainless steel is an ideal bipolar plate material for a proton exchange membrane fuel cell (PEMFC). However, the thickening of the passivation film on the stainless steel surface and the dissolution of corrosive ions during operation will affect the durability of the PEMFC. Herein, a heterogeneous layer is prepared on the surface of 316 L stainless steel through dual ion implantation of molybdenum ion and carbon ion combined with heat treatment to promote the corrosion resistance and conductivity of the bipolar plate. The ion implantation technique resulted in a uniform distribution of Mo and C elements on the surface of 316 L stainless steel, with a modified layer depth of about 70-80 nm. The electrical conductivity of the ion implanted samples was significantly improved, and the interfacial contact resistance was reduced from 464.25 mΩ × cm2 to 42.49 mΩ × cm2. Heat treatment enhances the surface homogenization, repairs the defects of irradiation damage, and improves the corrosion resistance of stainless steel. The corrosion current density of (Mo+C)-600 samples decreased from 1.21 × 10-8 A/cm2 to 2.95 × 10-9 A/cm2 under the long-term corrosion condition of 4 h. These results can provide guidance for the modification of stainless steel bipolar plates.

Sorption Of Rare Metal Ions by Ionite Based on Diglycidyl Thiourea and Various Amines

The article studies the process of sorption of molybdenum and vanadium ions on anion exchangers obtained on the basis of thiourea, epichlorohydrin and various amines. Various amines (urea, guanidine, melamine, polyethylene polyamine, ethylenediamine, etc.) are used as substances containing ionic groups. The regularities of ion exchange and the main properties of the tested anionites are given, the influence of the pH of the medium and interfering ions in the process of sorption of molybdenum and vanadium ions are studied. For vanadium, the use of empirical partition relations and of an extended Freundlich equation were tested, with promising results. The objective of this paper is to investigate the use of the pH dependent Freundlich model of Gustafsson et al., for describing vanadate(V) sorption to 26 mineral soils (all having less than 12% organic C), and to discuss the possible use of the model for risk assessments. The kinetic curves of the sorption process, the values of the diffusion coefficients for the initial periods of molybdenum sorption are given. In particular, the distribution coefficient of the radiotracers of 99Mo and 131I as homologs of Sg and Ts using the surface modification of chabazite was investigated as liquid-solid system in the present study. The kinetics of molybdenum sorption was carried out under static conditions from an ammonium molybdate solution with a concentration of 1 g/L for molybdenum ions and at pH 4.5–5. Under the same conditions, molybdenum ions are sorbed much faster by the DGT + M anion exchanger in comparison with AN-2F anion exchangers, in which the diffusion coefficient is much lower. The static exchange capacity (SEC) was determined in industrial solutions in the presence of mineral acids (hydrochloric, sulfuric and nitric), usually contained in them. The obtained kinetic equilibrium parameters of the tested anion exchangers were compared with those of industrial polycondensation anion exchangers, such as AN-2F and AN-1.

Advancing wastewater treatment and metal recovery: Aminated ZIF-8 composite cellulose aerogel as an innovative biomass adsorbent for enhanced molybdenum ion adsorption

Biomass adsorbents possess significant potential for both metal recovery from industrial leaching solutions and wastewater treatment. However, standalone biomass materials suffer from the drawback of low adsorption capacity. In this study, by the combination of metal–organic frameworks (MOFs) with organic biomaterials, a novel aerogel of aminated ZIF-8 composite cellulose (CPEZN) was developed for molybdenum ions adsorption, and the incorporation of aminated ZIF-8 improved the availability of reactive groups. The unique aerogel structure effectively prevented the accumulation of MOFs, thereby increasing the specific surface area and improving the exposure of active site. In addition, the positively charged surface of CPEZN effectively adsorbed molybdenum ions. Experimental results showed that the introduction of ZIF-8-NH2 improved the adsorption performance of the composites. The adsorption of Mo(VI) followed the Langmuir adsorption isotherm model, and its adsorption rate followed the pseudo-second-order model. The adsorbent exhibited a maximum Mo(VI) adsorption capacity of 872.39 mg/g at pH = 3, and a removal rate of more than 80 % in mixed coexisting ion solutions. Moreover, the adsorbent demonstrated good stability, with a removal rate of above 80 % after 5 cycles of adsorption. Comprehensive characterizations revealed that the adsorption mechanism of Mo(VI) on CPEZN was a synergistic effect of chemisorption, electrostatic interaction, redox, and complex ligand processes. The simulated industrial wastewater adsorption experiment showed that the prepared adsorbent had good removal ability for molybdenum ions. This study not only provides a reference for the design and preparation of MOF and biomass-based composite adsorbent materials, particularly in terms of understanding the adsorption mechanism and designing high-capacity functional groups, but also provides a theoretical basis for its practical application.

Targeted elimination of molybdenum ions from a leaching solution with the ability of radiated grafting GMA-PAN nanofibers

In this study, electrospun polyacrylonitrile nanofibers were effectively functionalized for enhanced molybdenum ion adsorption through a multi-step approach. Initially, glycidyl methacrylate was grafted onto the nanofibers via irradiation-induced grafting polymerization, followed by chemical modification with various amino groups, with triethylamine identified as the optimal modifier. The impacts of key synthesis parameters and reaction conditions on grafting level and adsorption capacity were thoroughly investigated, with a focus on achieving maximum efficiency. The resulting nanofibers were characterized using FTIR, SEM, and BET techniques, confirming the successful modification and structural features conducive to adsorption. Furthermore, a comprehensive experimental design, incorporating a central composite design, yielded optimal conditions for molybdenum adsorption, with key parameters including monomer concentration, irradiation dose, adsorbent mass, initial concentration, time, pH, temperature, and amine concentration. The adsorption kinetics were effectively described by the pseudo-second-order model, while the Langmuir isotherm model provided valuable insight into the adsorption behavior. Impressively, the adsorbent exhibited exceptional adsorption efficiency, surpassing 98% even after six adsorption–desorption cycles using 0.5 M HCl. Thermodynamic analysis revealed the exothermic nature of the adsorption process, along with decreased entropy and overall spontaneity, underlining the favorable conditions for molybdenum adsorption. Notably, the synthesized adsorbent demonstrated notable selectivity for molybdenum and achieved an impressive adsorption capacity of 109.79 mg/g, highlighting its potential for practical applications in molybdenum removal from aqueous solutions.