Ethylenediaminetriacetic Acid Research Articles

Separation of rare earth elements using chelation-assisted electrodialysis

Rare earth elements (REE) find crucial applications in electronics, clean energy, aerospace, automotive, and defense sectors. However, the conventional solvent extraction (SX) technique currently dominates the process of isolating individual REE into pure elements, presenting challenges due to its extensive stage requirements and environmental footprint. To address these limitations, this study explores chelation-assisted electrodialysis (ED) as a promising alternative to SX for efficiently separating light and medium REE from binary and tertiary solutions. By incorporating chelating agents into the ED process, we aim to enhance separation efficiency while mitigating the drawbacks associated with SX. A laboratory-scale ED system with a microflow cell consisting of five pairs of Neosepta® cation and anion exchange membranes in an alternating configuration was utilized. Aminopolycarboxylic acids such as Ethylenediaminetetraacetic acid (EDTA), diaminocyclohexanetetraacetic acid (DCTA), N-(2-hydroxyethyl) ethylenediaminetriacetic acid (HEDTA) and diethylenetriamine-pentaacetic acid (DTPA) were employed as chelating agents to increase the selectivity of REE separation. The effects of operating voltage, operation mode, pH, type of electrolytes, and membrane configuration on the separation process were investigated. ED was conducted at varying concentrations of REE and chelating agents, and the system was optimized for the highest separation factors. It was observed that the separation factors increased by increasing the voltage due to the higher ionic mobility of non-chelated REE at higher voltages. Precipitation of REE in ED compartments was one of the main challenges in the tests. To prevent the precipitation, a modified membrane configuration and an optimized pH window of 3.0–4.5 were applied. At optimized operating conditions, the REE separation factors of up to 42 were achieved, which were up to 20 times greater than those reported for the conventional SX process. The final REE concentrations in the concentrate compartment were comparable with those calculated from the dissociation equilibrium equations and in most cases, less than 10 % error was observed between the experimental results and the calculations.

Quantification of Chlorpyrifos Residues in Water under Thermodynamically Favorable Electrodics Using the f-MWCNT/N-(2-C2H5O) ED(CH3COONa)3 Composite of Superior Selectivity

Researchers are continually seeking potential alternatives to develop water quality sensors with higher selectivity to obtain the desired performance during real-time deployment. Quantification technologies involving interface materials of distinguishing capacity at elevated matrix complexity are desirable. However, there remains a challenge in designing suitable techniques, methodologies, and appropriate validations to support the grounds for the selection of interface materials of enhanced selectivity. The ability to monitor chlorpyrifos in analytical and commercial grade compounds and in the water matrix using an interface material of suitable states is the focus of this work. Herein, N-(2-hydroxyethyl) ethylenediamine triacetic acid trisodium (N-(2-C2H5O) ED(CH3COONa)3) incorporated with functionalized multiwalled carbon nanotube (f-MWCNT) is reported to provide thermodynamically favorable charge transfer for the quantification of chlorpyrifos residues under varying internal and external conditions with appropriate validations using density functional theory (DFT) and high-performance liquid chromatography (HPLC). The sensor exhibited excellent figures of merit such as limit of detection (LOD) and limit of quantitation (LOQ) of 9.7 pM and 29.4 pM, respectively.

EDTA-functionalized silica nanoparticles as a conditioning agent for dentin bonding using etch-and-rinse technique

ObjectiveThis study investigated the possibility of using ethylenediaminetetraacetic acid functionalized silica nanoparticles (EDTA-SiO2) as a dentin-conditioning agent using etch-and-rinse technique to promote the durability of dentin bonding. MethodsThe SiO2-EDTA were synthesized by N- [(3- trimethoxysilyl) propyl] ethylenediamine triacetic acid (EDTA-TMS) and SiO2 (50 nm), then characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The capacity of SiO2-EDTA to chelate calcium ions from dentin was examined by inductively coupled plasma-optic emission spectrometry (ICP-OES). The dentin surfaces conditioned with SiO2-EDTA were detected by field emission scanning electron microscopy (SEM), TEM and microhardness testing. For dentin bonding, dentin surfaces were adopted wet- or dry-bonding technique and bonded with adhesive (AdperTM Single Bond2) and applied composite resin (Filtek Z350) on them. The durability of dentin bonding was evaluated by mircotensile bond strength test, in-situ zymography and nanoleakage testing. ResultsFTIR, TGA and XPS results showed that SiO2-EDTA contained N element and carboxyl groups. SEM, TEM and microhardness results indicated that SiO2-EDTA group created extrafibrillar demineralization and retained more intrafibrillar minerals within dentin surface. In the dentin bonding experiment, SiO2-EDTA group achieved acceptable bond strength, and reduced the activity of matrix metalloproteinase and nanoleakage along bonding interface. ConclusionIt was possible to generate a feasible dentin conditioning agent (SiO2-EDTA), which could create dentin extrafibrillar demineralization and improve dentin bond durability. Clinical significanceThis study introduces a new dentin conditioning scheme based on SiO2-EDTA to create extrafibrillar demineralization for dentin bonding. This strategy has the potential to be used in clinic to promote the life of restoration bonding.

A chemically tailored capacitive deionization system for the enhanced removal of cesium from process water

A capacitive deionization (CDI) electrode comprising ethylenediamine triacetic acid (EDTA) and 2D MXene (EDTA-MXene) is fabricated to separate Cs+ from strongly acidic process water. The method provides new direction for an advanced aqueous recycle process to separate fission products from spent fuel liquor. Grafting EDTA on MXene has no detrimental effect on its structure but does diversify the modes of ion interaction and increase the number of binding sites. The composite CDI electrode has a Cs+ adsorption capacity of 2.07 mmol g−1 at 1.2 V with 97.3% removal efficiency within 15 min. Step-wise adsorption and desorption cycling of the electrode highlights the chemisorption effect of EDTA which immobilizes the ions as the applied voltage is lowered, although almost all ions can be stripped by reversing the voltage to −1.4 V and without the need for chemical treatment. The EDTA-MXene electrode demonstrates outstanding cyclic performance with a capacity retention of >80% after 320 cycles. Furthermore, the electrode maintains its performance in strongly acidic solution, removing 0.66 mmol g−1 Cs+ at 1.2 V, as well as being stable after immersing in 3 mol L−1 HNO3 for 7 days. Through continuous cycling it is possible to enrich the Cs+ into a highly concentrated solution for element recovery or safe disposal. The EDTA-MXene material is robust and maintains good performance in harsh chemical environments, levering its multiple binding sites to successfully isolate Cs+ from strongly acidic solutions and in the presence of competing ions, Sr2+ and Ce(IV).

Experimental Investigations of Acid Fracturing in Layered Carbonate Rocks Utilizing Chelating Agents

One of the methods to improve carbonate formation productivity is acid fracturing. The acid injection creates dissolution along the fracture, which improves fracture conductivity. This study investigated chelating agents such as glutamic diacetic acid and ethylene diamine triacetic acid on acid fracturing treatments to sustain the conductivity of layered minerals of carbonate formations. Chelating agents are less reactive than HCl and do not need large quantities of corrosion inhibitors, especially in high-temperature environments. Three cylindrical samples of 1.5 in. × 6 in. were cored from casted layered calcite and dolomite. The roughness and hardness of the fracture surface before and after the stimulation have been examined. The fracture conductivity was also evaluated before and after acid etching using a core flooding setup at different flow rates under four closure stress values. Inductively coupled plasma analysis has been carried out to estimate rock dissolution based on quantifying calcium and magnesium ions. Results showed that chelating agents have improved fracture conductivity and resulted in a sufficiently rougher fracture surface compared to HCl. The rock samples’ surface hardness has been reduced relatively post-treatment, with chelating agents being gentler on the rock. The novelty of this study is that for the first time, chelating agents have been tested as acid fracturing fluids on carbonate reservoirs for generating sustainable conductivity.

Effects of DTPA, HEDTA, and EDDS on the Growth of Watermelon and Chemical Properties of Plastic Film House Soil

A chelating agent helps crops to reuse as nutrients by mobilizing salts from the soil. This study was conducted to evaluate the effects of Diethylenetriamine pentaacetic acid (DTPA), N-(2-hydroxyethyl)-ethylene diaminetriacetic acid (HEDTA), and Ethylene diamine disuccininc acid (EDDS) for improving plant growth and reusing accumulated nutrients in soils of plastic film house. Two experiments were carried out of follows: i) For the incubation test, the availability of nutrients were examined for soils treated with distilled water, 1 mM of DTPA, HEDTA and EDDS solutions. ii) In the pot test, the impacts of watermelon growth response were examined by adding 0.5, 1, and 5 mM of chelating agent to soil. In incubation test, application of chelating agents increased the availability of soil nutrients in the following order : DTPA ≒ HEDTA > EDDS > distilled water. However, biomass of watermelon in pot test, tended to be highest in EDDS 1 mM. The absorption amount of N, P, and K of crop in EDDS 1 mM was similar to that of NPK treatment and K, Ca, Mg, and Fe tended to be high. Soil Electrical conductivity (EC) of 1 mM EDDS showed a 66% decrease compared to no treatment. These results showed that EDDS could be improved the watermelon growth. Further research is needed to evaluate the effects of EDDS for plant growth on field scale.Difference in watermelon biomass by chelating agents (DTPA, HEDTA, and EDDS) and their concentrations (0.5, 1, and 5 mM) treated in salt-accumulated soil under pot scale (†Duncan’s multiple range test (p < 0.05), ‡Relative biomass percent of other treatments compared to NPK).

Label-free dynamic light scattering assay for C-reactive protein detection using magnetic nanoparticles

In this work, we present a simple method for label-free detection of C-reactive protein (CRP) in diluted saliva samples without the use of specific molecules against CRP. We use the dynamic light scattering (DLS) technique and silica-coated Fe3O4 nanoparticles (∼50 nm in diameter) functionalized with amino carboxylate moieties (Fe3O4@SiO2/COOH) as probes. After contact with the sample, the particles could be easily separated with a handy magnet and redispersed for DLS analysis simply by vortex shaking. The variation of the hydrodynamic diameter of the nanoparticles (Z-average size) could be correlated with the concentration of CRP up to concentrations of 10 mg L−1. The detection limit (LOD) in diluted saliva samples that were spiked with CRP was 0.205 mg L−1, which is below salivary levels of CRP detected in unhealthy individuals. The coefficient of variation was found to be less than 1.5% in the entire detection range. The variation of Z-average size of non-functionalized silica coated nanoparticles (Fe3O4@SiO2) also correlated well with CRP concentration. Nevertheless, the Fe3O4@SiO2/COOH nanoparticles were less susceptible to interference from other biomolecules present in saliva and adsorbed more CRP, indicating higher selectivity toward CRP than nonfunctionalized nanoparticles. This higher affinity was attributed to the chelating interaction between the aminocarboxylate groups of the organosilane N-[3-(trimethoxysilyl)propyl]ethylenediaminetriacetic acid trisodium salt (EDTA-TMS) grafted onto the surface of the Fe3O4@SiO2/COOH nanoparticles and the Ca2+ ions of CRP. LC-MS/MS analyses allowed identification of the proteins adsorbed on the nanoparticles and confirmation of the presence of CRP, which is involved in several biological processes, including immune response, response to stress and transport.

In situ Functionalized Mesoporous Silicas for Sustainable Remediation Strategies in Removal of Inorganic Pollutants from Contaminated Environmental Water.

Low-cost mesoporous silicas of the SBA-15 family were prepared, aimed for removal of a broad spectrum of both cationic and anionic forms of hazardous metal pollutants (Cr(III, VI), Mn(II, VII), Pb(II), Cd(II), and Cu(II)) from environmental water. Series of mono- and bifunctional materials with immobilized ethylenediaminetriacetic acid (EDTA), primary amine (NH2), and quaternary ammonium (QAS) groups were prepared in a cost-efficient one-step synthesis using two silica sources, low-cost sodium metasilicate (Na2SiO3 9H2O) and the conventional source—tetraethylorthosilicate (TEOS). The functionalized SBA-15 samples obtained from both silica sources were highly ordered, as evidenced by TEM and SAXS data. All obtained materials were mesoporous with high surface area values of up to 745 m2/g, pore volumes from 0.99 to 1.44 cm3/g, and narrow pore distributions near 7 nm. The adsorption affinity of the EDTA-functionalized samples followed the common order Pb(II)> Cd(II)> Cu(II)> Cr(III)> Mn(II), which could be explained based on the Pearson theory. The highest adsorption capacities were observed for samples functionalized by EDTA groups using TEOS for synthesis (TEOS/EDTA): 195.6 mg/g for Pb(II), 111.2 mg/g for Cd(II), 58.7 mg/g for Cu(II), 57.7 mg/g for Cr(III), and 49.4 mg/g for Mn(II). Moreover, organic matter (humic acid up to 10 mg/L) and inorganic (Na(I), K(I), Mg(II), Ca(II), etc) macrocomponents present in environmental water had almost negligible effect on the removal of these cations. The NaSi/EDTA/NH2 sample revealed a better selectivity compared to the NaSi/NH2 sample towards such species as Cr(III), Mn(II), Cd(II), and Cu(II). The chromate-ions uptake at pH 7.5 by the TEOS/QAS sample turned practically unaffected by the presence of doubly charged anions (CO32–, SO42–). The content of functional groups on the surface of MS decreased only slightly (∼1–5%) after several regeneration cycles. The complete desorption of all heavy metal ions can be achieved using 1 mol/L EDTA solution. Reusability tests demonstrated the complete stability of the adsorbent for at least five to six consecutive adsorption/desorption cycles with no decrease in its adsorption characteristics compared to those obtained by 0.05 mol/L HNO3 treatments. The synthesized mesoporous materials were evaluated for removal of the heavy metal ions from drinking and different natural water samples, proving their potential as sustainable, effective, and cost-efficient adsorbents.

Direct synthesis of efficient silica-based adsorbents carrying EDTA groups for the separation of Cu(II) and Ni(II) ions

Cations of copper and nickel belong to the category of heavy metals that coexist in wastewater from the mining and chemical industries and have similar structures. Selective extraction of their soluble forms is an urgent task in ecoanalytical chemistry. In this study, spherical organosilica particles with ethylenediaminetriacetic acid (EDTA) chelating groups were prepared via a one-pot approach for the purpose of Cu(II) and Ni(II) cation extraction from aqueous solutions. The isoelectric point for such samples is observed at pH = 2–3. It was found that the order of introduction of different components (Si(OEt)4, EDTA–silane) into the reaction solution significantly affects the morphology, particle size (672–915 nm) and porosity (260–447 m2 g–1), without affecting the number of chelating groups (0.56–0.59 mmol g–1) and the sorption capacity. The polysilsesquioxane samples acquired from bis-silane with ethylene bridge and EDTA–silane showed a similar number of EDTA groups (0.93–1.11 mmol g–1) regardless of the silane ratio, with the possibility of controlling the specific surface area values (10–431 m2 g–1) and particle size (300–1200 nm) by varying the proportion of bridged silane. The EDTA-polysilsesquioxanes exhibited sorption capacity up to 1.72 mmol g–1 for Cu(II) and 1.53 mmol g–1 for Ni(II). These samples containing EDTA and silanol groups can be effectively used for the selective removal of copper(II) ions from the cationic mixture by varying the initial pH value of the solution.

Electrodeposition of Crystalline Germanium on Glass

The research objective of this work is to test the hypothesis that crystalline germanium can be deposited on insulating substrates through electrochemical-liquid phase epitaxy (ec-LPE). In doing so, this work establishes a new method of semiconductor-on-insulator fabrication. Semiconductor-on-insulator device constructs are at the heart of all modern electronics. Methods that simplify fabrication by lowering the thermal budget and eliminating hazardous precursors are highly desirable. Recently, a new method for the direct preparation of covalent semiconductor crystals at ambient conditions, ec-LPE, was demonstrated by our group. This method utilizes thin liquid metal films simultaneously to perform electrochemical reduction of precursors and to direct heterogeneous nucleation at an underlying substrate of interest. In this work, the fabrication of germanium-on-glass using ec-LPE is demonstrated for the first time. Amperometry, microscopy, and Raman spectroscopy will be presented to demonstrate the proof of principle, i.e. the growth of Ge crystals electrochemically on insulating glass. The surface chemistry of glass substrates will be discussed, including glass functionalized with (3-Aminopropyl)triethoxysilane (APTES), and N-(Trimethoxysilylpropyl)ethylene-diamine triacetic acid (EDTA–TMS). Surfaces with a higher chelating group density improved the efficacy of Ge ec-LPE. These results set the groundwork for semiconductor-on-insulator process development based on ec-LPE.

Analysis of Protonation Mechanisms for Models of Surface Complexes of N-(Propyl)ethylenediaminetriacetic Acid with Silica

Analysis of Protonation Mechanisms for Models of Surface Complexes of N-(Propyl)ethylenediaminetriacetic Acid with Silica

Synthesis of Hafnium(IV) Polyaminoacetates.

The interaction of hafnium(IV) salts (oxide-dichloride, chloride, and bromide) with nitrilotriacetic acid (NTA), diethylenetriamminepentaacetic acid (DTPA), 1,2-diaminocyclohexanetetraacetic acid (CDTA), 1,3-dipropylmino-2-hydroxy N,N,N′,N′-tetraacetic acid (dpta), and N-(2-hydroxyethyl)ethylenediamine triacetic acid (HEDTA) has been studied. The corresponding complexes Na2[Hf(NTA)2]·3H2O (1), Na[HfDTPA]·3H2O (2), [HfCDTA(H2O)2] (3), and Na[Hf2(dpta)2]·7.5H2O·0.5C2H5OH (4) have been isolated and characterized and their structures have been determined by single crystal X-ray diffraction. Biological studies of [HfCDTA(H2O)2] have shown that in 5% glucose solution this complex has low toxicity and good contrasting ability.

Oriented Hexagonal Phase NaGdF4:Eu3+ Films Made through Electrodeposition

Hexagonal phase NaGdF4:Eu3+ thin films with (110) preferred orientation were made by electrodeposition onto fluorine doped tin oxide (FTO) conductive glass in an aqueous solution in which N-(2-Hydroxyethyl) ethylenediaminetriacetic acid (HEDTA) acted as a complexing agent coordinating with rare earth ions (RE3+) to form RE3+-HEDTA as precursor. The in situ electrochemical quartz crystal microbalance and cyclic voltammetry methods were applied to study the mechanism and initial process of electrodeposition of NaGdF4:Eu3+ films. The structures and morphologies of films were observed by XRD and SEM and they were varied with applied potential and deposition temperature. As for down conversion property, oriented NaGdF4:Eu3+thin film shows much stronger emission intensity and higher quantum yield than its less-oriented film.

Enhanced Removal of Cr(III), Mn(II), Cd(II), Pb(II) and Cu(II) from Aqueous Solution by N-functionalized Ordered Silica

Chelating and ion-exchange N-functionalized mesoporous silicas (SBA-15) as selective adsorbents for removal of heavy metals were synthesized using template method. Fourier transform infrared spectroscopy, TEM analysis, N2 adsorption/desorption isotherms and titration analysis confirmed successful functionalisation of the tri-sodium salt of N-(triethoxysilylpropyl)ethylenediaminetriacetic acid (EDTA), protonated primary amine (NH3+Cl−) and its combinations onto the mesoporous silica (SBA-EDTA/NH2). The obtained materials featured beneficial properties of mesoporous silica SBA-15 with its high surface area and were successfully fictionalized with N-containing groups. The synthesized series of silicas were investigated for removal of Cr(III), Mn(III), Pb(II), Cd(II) and Cu(II) from model water solutions. The adsorption of target ions increased with the increase pH and its concentration in solution. The adsorption equilibrium data were well fitted to Langmuir isotherm model and maximum monolayer adsorption capacities for cations Pb(II), Cd(II), Cr(III) and Mn(II) were 185.6 mg g−1, 111.2 mg g−1, 57.7 mg g−1 and 49.4 mg g−1, respectively. The chelating interaction was considered as the main adsorption mechanism for metal ions (Cr(III), Mn(II), Pb(II), Cd(II), and Cu(II)). The adsorption capacities of SBA-EDTA and SBA-EDTA/NH2 samples toward studied metal ions were consistent with the Lewis ‘hard and soft acids and bases’ theory. The metal removal efficiency of adsorbents was near 96–92% during three regeneration cycles. All these results indicated that the produced N-functionalized silica were promising for applications in environmental and analytical separation fields.

Enhanced Removal of Pb(II) from Aqueous Solution using EDTA‐Modified Magnetic Graphene Oxide

AbstractEthylenediaminetetraacetic acid (EDTA) groups are successfully linked to magnetic graphene oxide (MGO) by a silanization reaction between N‐(trimethoxysilylpropyl) ethylenediaminetriacetic acid and OH on the surface of MGO. The EDTA‐modification enhances the adsorption capacity of MGO because of the chelating ability of EDTA. The adsorption behavior of Pb(II) and the effects of solution conditions such as contact time, initial Pb(II) concentration, and pH (1–9) are investigated. The adsorption capacity for Pb(II) removal is found to be 211.3 mg g−1 and the adsorption process is completed at pH 6.8 within 50 min. The process is shown to follow a pseudo‐second‐order kinetic rate. The isothermal data reveal that the adsorption process of Pb(II) is well‐matched with the Freundlich model. In addition, the magnetic composite can be effectively and simply separated by an external magnetic field. Therefore, MGO‐EDTA can potentially serve as an adsorbent for the separation and removal of Pb(II) from water.

Masking Ability of Various Metal Complexing Ligands at 1.0 mM Concentrations on the Potentiometric Determination of Fluoride in Aqueous Samples.

Fluoride is a common anion present in natural waters. Among many analytical methods used for the quantification of fluoride in natural waters, potentiometric analysis is one of the most widely used methods because of minimum interferences from other ions commonly present in natural waters. The potentiometric analysis requires the use of ionic strength adjusting buffer abbreviated as TISAB to obtain accurate and reproducible data. In most of the reported literature, higher concentrations of strong metal chelating ligands are used as masking agents generally in the concentration range of 1.0 to 0.01 M. In the present study, effectiveness of the masking agents, phosphate, citrate, CDTA ((1,2-cyclohexylenedinitrilo)tetraacetic acid), EDTA (ethylenediaminetetraacetic acid) HE-EDTA ((hydroxyethyl)ethylenediaminetriacetic acid)), triethanolamine, and tartaric acid at 1.0 mM in TISAB solutions was investigated. The experimental data were compared with a commercially available WTW 140100 TISAB solution as the reference buffer. According to the experimental data, the reference buffer always produced the highest fluoride concentrations and the measured fluoride concentrations were in the range of 0.611 to 1.956 mg/L. Out of all the masking agents investigated, only CDTA performed marginally well and approximately a quarter of the samples produced statistically comparable data to the reference buffer. All the other masking agents produced significantly low concentrations compared to the reference buffer. The most probable reasons for the underestimation of fluoride concentrations could be shorter decomplexing time and lower masking agent concentrations.

Determination of the tungsten isotope composition in seawater: The first vertical profile from the western North Pacific Ocean

The stable isotope ratio of W is a new tracer in oceanographic studies and a new proxy in paleoceanographic studies; however, precise data for modern seawater have not been reported to date. Because the concentration of W in seawater is as low as 49 pmol kg−1, an ~3000-fold preconcentration is necessary prior to measurement by multicollector inductivity coupled plasma mass spectrometry (MC-ICP-MS). For the preconcentration, we investigated solid-phase extraction using chelating resins, namely, NOBIAS Chelate-PA1 with ethylenediaminetriacetic acid groups and TSK-8HQ with 8-hydroxyquinolie groups. We report that TSK-8HQ is useful because the effects of the seawater matrix are minor thermodynamically and kinetically. We present a novel method for analysis of the concentrations and isotope ratios of W and Mo in seawater, consisting of solid phase extraction, chromatographic separation using anion exchange resin AG1 X8, and measurement by MC-ICP-MS. Both W and Mo are quantitatively recovered by this method, which was applied to seawater samples collected from the North Pacific Ocean. The measured concentration of W and the concentration and isotope ratio of Mo are consistent with those in the literature. The isotope ratio of W is found to be uniform throughout the water column in the western North Pacific Ocean; δ186/184W is 0.55 ± 0.12‰ (ave ± 2sd, n = 7) using NIST SRM 3163 as a reference for W. On the basis of this data, we determined that the isotopic difference in δ186/184W is ~0.49‰ between seawater and oxic sediments in the modern ocean. This value accords with the reported experimental data for the isotope fractionation of W during adsorption on manganese and iron (oxyhydr)oxides, suggesting the validity of our data.

Advanced core-shell EDTA-functionalized magnetite nanoparticles for rapid and efficient magnetic solid phase extraction of heavy metals from water samples prior to the multi-element determination by ICP-OES.

A method for preconcentration and simultaneous determination of trace heavy metals in water media by core-shell superparamagnetic nanoparticles with the immobilized derivative of ethylenediaminetriacetic acid (referred to as MNPs/SiO2-EDTA) is proposed. The specific layer-by-layer covering of magnetite endowed the new material with essentially increased chemical stability of MNPs including acidic media and improved the affinity toward traces of toxic metal ions. The initial and modified materials were characterized by X-ray powder diffraction, Fourier transform infrared spectroscopy, transmission and scanning electron microscopies, elemental analysis, and vibrating sample magnetometry. The obtained particles were nanodimensional with a7-12-nm magnetic core and a4-6-nm silica shell. The MNPs/SiO2-EDTA quantitatively removes heavy metals from contaminated media at pH ≥ 3.5 within 15min. The adsorption data were successfully fitted to the pseudo-second-order kinetic model. The preconcentration factor was 150 and maximum adsorption capacity was 36.9mgg-1 for Cu(II), 108.8mgg-1 for Pb(II), 30.9mgg-1 for Zn(II), 34.32mgg-1 for Cr(III), and 59.5mgg-1 for Cd(II). Due to high stability in the wide range of pH, the magnetic adsorbent can be regenerated at least six times using0.1M HNO3. Following adsorption/desorption, determinationof metal ions isprovided by inductively coupled plasma optical emission spectrometry (ICP-OES) . The linear range of theproposed method is 0.1 - 200μgL-1. The limits of detection (LOD) are 0.12μgL-1 for Zn(II); 0.06μgL-1 for Cd(II); 0.39 for Cu(II); 0.15μgL-1 for Cr(III); and 0.76μgL-1 for Pb(II). The method performance was evaluated in the analysis of environmental, tap, and wastewater samples with recoveries in the range of 94.0-104.0%.

CAN COPPER AND ZINC IN DIFFERENT CHEMICAL FORMS CAN IMPROVE IRON DEFICIENT IN PHASEOLUS PLANT

This study was aimed to compare between the effects of different chemical forms of Zn and cupper[ionic forms (CuSO4), (Zn SO4) and chelated forms of [Cu Zn (II) HEDTA and Cu (II) HEDTA], whereas, HEDTA is N-(hydroxyethyl) ethylenediamine triacetic acid, applied at micromolar concentrations in the nutrient solution] of Phaseolus Vulgaris plants grown hydroponically under conditions of iron deficiency (- Fe) were investigated. Plant variants (– Fe + 2 µM Cu2+) and (– Fe+ 20 µM Zn2+) with extremely strong chlorosis were examined for investigations to take after the recuperation of leaf greening after treatment with Cu(II)HEDTA created leaf greening in the two variations, particularly strong for the recently which created leaf, as it appeared with chlorophyll estimations. Changes of plasma membrane reductase movement (PMRA) in roots after treatment with ionic or chelated copper were followed in (+Fe) and (– Fe) plants. The results show the increment of ferric-chelate reductase action (with substrate of Fe (III) HEDTA). Then, the cupric-chelate Cu (II) HEDTA, connected at similar level in arrangements with (– Fe) plants, kept up the high encouragement of plasma membrane ferric-chelate reductase activity. It can be concluded that the treatment with Cu (II) HEDTA enhanced the development and root plasma membrane reductase activity (PMRA) and additionally iron deficiency reactions of phaseolus plants. Regard to cell compounds increase, measurements of 20 μM of Zn altogether developed the action of the protein superoxide dismutase and peroxidase.

Preparation of highly dispersed supported Ni-Based catalysts and their catalytic performance in low temperature for CO methanation

The use of non-noble nickel-based catalysts for low temperature CO methanation has been a challenge in recent years. Herein, MgAl layered double oxides sample with high dispersion synthesized by a facile N-(2-Hydroxyethyl) ethylenediaminetriacetic acid assisted wetness impregnation approach, demonstrates much superior catalytic activity and exceptional stability for CO methanation in comparison with the classical Ni/MgAl-LDO catalyst prepared by the ordinary wetness impregnation method. HRTEM results showed that N-(2-Hydroxyethyl)ethylenediaminetriacetic acid played a positive role in the dispersion of Ni, as well as Ni-support interaction. Well-dispersed Ni particles with a size of about 5 nm were formed in the presence of N-(2-Hydroxyethyl) ethylenediaminetriacetic acid. Compared to the Ni/MgAl-LDO prepared by conventional impregnation method, the NH-Ni/MgAl-LDO exhibited superior catalytic performance, especially excellent thermal stability. The NH-Ni30/MgAl-LDO catalyst was found to keep a 70 % CO conversion even at 160 °C which demonstrates its good low temperature performance. From the in situ FTIR observations, this good performance at low temperatures may be linked to the delocalization of electrons around CO caused by surface hydroxyl groups.