Effect of Combined Treatments of Phytohormones and Chelating Agents on the Accumulation Capacity of Amaranth

[Objective] To explore a high efficient phytoremediation technology for soil pollution. [Method] Foliage application and root irrigation were carried out to study the influence on amaranth repair efficiency by using combined treatments of phytohor- mones （IAA, GA3 SA） and chelating agents （EDTA）. [Result] The combined treatment increased the biomass of amaranth under 133Cs, 88Sr, Cr stress The 133Cs, 88Sr, Cr enrich- ment in amaranth by root irrigation were obviously higher than that by foliage appli- cation. The phytoextraction efficiency of phytohormones and chelating agents from best to poor was as following： 100 mg/L SA＋1.5 mg/kg EDTA, 500 mg/L GA3＋1.5 mg/kg EDTA, 100 mg/L IAA＋1.5 mg/kg EDTA. [Conclusion] The most appropriate treatment was the combined treatment of 100 mg/L SA＋l.5mg/kg EDTA by soil irri- gation, which could make the total absorption doses of 133Cs, 88Sr, Cr per plant achieve the maximum.

STUDIES ON THE COMPETITION FOR CADMIUM ION BETWEEN CHELATING AGENTS AND BOVINE SERUM ALBUMIN

Eleven chelating agents were studied for their capabilities to mobilize the cadmium bound tp bovine serum albumin(BSA).The parameter F,which is defined as the ratio between the percentages of cadmium bound to BSA in the presence and absence of chelating agents,can be used as the criterion to evaluate the mobilizing capability of chelating agent.The F values determined experimentally lead to a mobilizing capability order:DTPA>EDTA>EGTA>NTA>TR1EN>PEN>CYS>HIS>SAThe polyaminopolycarboxylate type chelators mobilize cadmium effectively.A linear relationship was found between 1gF and lg k'CdL (conditional stability constant of the cadmium chelate).

A feasibility study on cleaning Pb-contaminated soil with chelating agents

In this paper, the complexing abilities of EDTA, TTHA and Cit. with lead in the Pb(2.59 mg/g) contaminated soil were compared in the laboratory. Possibilities for lead and the threeagents to develop stable complexes increased proportionally to the growth of lead complexible formwhen the PH values ranged between 4 and 6. Under acid conditions, logB_(Pb-TTHA)) valued as 28.1 wasmuch higher than logB_(Pb-EDTA), as 18.0 depending on producing Pb_2-TTHA (logK_(Pb_2-TTHA= 11 0) andPb-HTTHA (logK(Pb-HTTTHA)=8.2)). Conclusively, the complexing ability of TTHA with Pb still ex-aseded that of EDTA by about 10% even when the amount of TTHA added was only equal to onefourth of that of EDTA. Due to the lower cost and less harzn to crops, Cit. can still be taken as abetter chelating agent in acid soil although its coordinative capability with Pb was weaker thanEDTA and TTHA.

Catechol-Bisphosphonate Conjugates: New Potential Chelating Agents for Metal Intoxication Therapy

In a quest for better chelating therapy drugs for the treatment of intoxication by Fe, Al, oractinides, two new series of mixed catechol-bisphosphonate through amide linkage were synthesized.Benzyl group was used as protecting group to avoid the breakage of amide by acid hydrolysis orimcomplete reaction in silylation-dealkylation using bromotrimethylsilane.

Effect of the chelating agents on bio-sorption of hexavalent chromium using Agave sisalana fibers

The current work is focused on the study of the bio-sorption of hexavalent chromium from aqueous solution using sisal natural fiber(Agave sisalana) treated by various chelating agents(ligands) such as urea(UR),thiocarbamide(TC), ethylenediaminetetraacetic acid(EDTA), and diphenyl carbazide(DCZ). The fiber treatments were investigated using Fourier Transform Infrared Spectroscopy(FTIR) and Scanning electron microscope(SEM). The kinetics of chromium bio-sorption was studied in batch presses under the effect of some physicochemical factors such as the nature of chelating agent(F@UR, F@TC, F@DCZ, and F@EDTA),adsorbent dose(2–10 g·L^(-1)), chromium initial concentration(100–500 mg·L^(-1)), solution pH(1–6), and batch temperature(20 ℃–50 ℃). This study resulted in an optimum adsorption at a chromium initial concentration of 100 mg·L^(-1), at pH 2, and at 20 ℃. The obtained results showed clearly that the treatment with chelating agent boosts the adsorptive capacity of A. sisalana fibers Cr(VI) 10.9 mg·g^(-1) to 58.6 mg·g^(-1). The modeling study showed that the adsorption kinetics obey the pseudo-second-order model, with an R2 in the range of 0.991 and 0.999. The bio-sorption isotherms followed the Langmuir model; the maximum uptake capacity of(F@N, F@UR,F@TC, F@DCZ, and F@EDTA) was found to be respectively, 12.3 mg·g^(-1), 25.33 mg·g^(-1), 28.73 mg·g^(-1),42.54 mg·g^(-1), and 61.45 mg·g^(-1). The determined adsorption thermodynamics parameters such as enthalpy,free energy, and entropy showed that the adsorption process is exothermic, spontaneous, and has a stable configuration.

Influence of Different Chelating Agents on Corrosion Performance of Microstructured Hydroxyapatite Coatings on AZ91D Magnesium Alloy

To improve the bioactivity and corrosion resistance of AZ91 D magnesium alloy,hydroxyapatite（HAp） coatings with novel microstructured morphologies were prepared successfully on AZ91 D substrates via a facile hydrothermal method.Different chelating agents including polyaspartic acid（PASP） and ethylenediaminetetraacetic acid（EDTA） were introduced to investigate their effects on the morphology and corrosion resistance of the coated magnesium alloys.The results revealed that the coating prepared with PASP was composed of many uniform urchin-like microspheres,while the coating prepared with EDTA consisted of many flower-like particles.Moreover,the crystallinity of the coating prepared with EDTA was much higher than that of the coating prepared with PASP.Electrochemical tests revealed that the corrosion resistance of the substrate was significantly improved after being coated with each coating.Immersion test of the coated samples in simulated body fluid（SBF） demonstrated that the coatings could be biodegraded gradually and induce the formation of calcium phosphate particles.

Influence of Chelating Agents on Chromium Fate in Sediment

A laboratory investigation on reaction between chelating agents and chromium was conducted to evaluate the effect of chelating agents on the adsorption and desorption of chromium in sediment. The amount of adsorbed chromium(VI) in sediment decreased slightly by 5%-10% because of addition of chelating agents.Chelating agents inhibited the remodel of Cr(Ⅲ) by sediment from solutions and the inhibiting effect was in the order:citric acid > tartaric acid > EDTA, salicylic acid.No effect of chelating agents on desorption of chromium in sediment was observed.

IMPROVEMENT OF BLEACHING OF KAOLIN USING CHELATING AGENTS

Bleaching of the kaolin ore from Shaziling Kaolin Mine in Jiangxi Province of China was studied with the aim of enhancing the quality and value of the ore to meet the requirements from the ceramics manufacturers. Factors affecting the reductive bleaching of kaolin ore with sodium dithionite as the bleaching agent were studied and optimized to increase the whiteness of the kaolin ore from 38. 5% to about 65%. However, it was found that in the conventional bleaching process, a washing step to remove the ferrous ions from the bleached kaolin suspension was indispensable, which made the process complicated and restricted the capacity of the production. In addition, the whiteness of the bleached kaolin products was unstable. To solve the above problems, a new technique with the application of chelating agents in the bleaching process was developed to remove ferrous ions and get rid of the washing step. The bleaching process of kaolin was simplified. The whiteness of the bleached kaolin products was stabilized as well as increased to about 70%. The mechanism of the bleaching process and the action of the chelating agents were discussed.

Annealing effects on the structural and optical properties of ZnO nanoparticles with PVA and CA as chelating agents

The effects of annealing temperatures and chelating agents on the structural and optical properties of ZnO nanoparticles were investigated.The average particle size of ZnO nanoparticles increased with increase of annealing temperatures.The decrease of the full width at half maximum(FWHM)with increasing annealing temperatures inferred increase of particle/grain growth.The grain sizes were also observed to be increased with increase of annealing temperatures.From the absorption spectra of the samples,the absorption was red-shifted and the energy band gap was blue-shifted with increase of annealing temperatures.A sharp UV emission peak was observed and the intensity of this peak increased with annealing temperatures corresponding to the high crystallinity in the samples.At high annealing temperature of 700℃,ZnO exhibited a less intense deep level emission.This negligible deep level emission was attributed to the oxygen vacancies created at higher annealing temperatures.

Environmentally relevant concentrations of aminopolycarboxylate chelating agents mobilize Cd from humic acid

Although Cd is a pollutant of public health relevance,many dietary sources from which it can be absorbed into human tissues remain unknown.While it is well established that the biogeochemical cycle of Cd involves its complexation with environment-derived ligands（e.g.,humic acids,HAs） and anthropogenic ones（e.g.,chelating agents,CAs）,the interaction of Cd with both of these ligands is less well understood.To gain insight,a HA–Cd complex was injected on a size-exclusion chromatography（SEC） column coupled on-line with a flame atomic absorption spectrometer（FAAS） using 10 mmol/L Tris buffer（pH 8.0） as the mobile phase.This approach allowed us to observe the intact HA–Cd complex and the retention behavior of Cd as a function of 2–20 μmol/L concentrations of ethylenediaminetetraacetic acid（EDTA）,diethylenetriaminepentaacetic acid（DTPA） or methylglycinediacetic acid（MGDA） that were added to the mobile phase.An increase of the retention time of Cd was indicative of a partial or complete abstraction of Cd from HA.Our results revealed that all CAs abstracted Cd from the HA–Cd complex at concentrations of 5 μmol/L,while MGDA and DTPA were effective at 2 μmol/L.The bioavailability of some of the on-column formed CA–Cd complexes explains the previously reported increased accumulation of Cd in periphyton in the ecosystem downstream of wastewater treatment plants.In addition,our results imply that the use of effluents which contain CAs and Cd for the irrigation of food crops can introduce Cd into the food supply and compromise food safety.

Chelating agents role on phase formation and surface morphology of single orthorhombic YMn_2O_5 nanorods via modified polyacrylamide gel route

YMn2O5nanorods were synthesized through a modified polyacrylamide gel route.The synthesis strategy in this work is based on a sol-gel process using a polyacrylamide gel method in which oxalic acid,citric acid or tartaric acid is employed as the chelating agent.In the gel routes,oxalic acid was used as a carboxyl chelating agent,while citric acid or tartaric acid was a carboxyl and hydroxyl chelating agent.The as-prepared samples were characterized by means of techniques such as X-ray powder diffraction(XRD)measurement,thermogravimetric analysis(TG),differential scanning calorimetry analysis(DSC),Fourier transform infrared spectroscopy(FTIR),X-ray photoelectron spectroscopy(XPS),thermal expansion measurement and field-emission scanning electron microscopy(SEM)investigations.It was found that oxalic acid is the best chelating agent with Y(NO3)3·6H2O and Mn(CH3COO)2·4H2O as precursors to prepare a single orthorhombic YMn2O5nanorods at 1000°C.Scanning electron microscope observation shows that the morphology of YMn2O5powders is significantly dependent on the chelating agent.The peaks(single orthorhombic YMn2O5nanorods)at 642,600,573,546,521,493,486,468,448 and 400cm?1were observed from FTIR spectra.The phase,surface morphology and chelation mechanisms of YMn2O5samples have been discussed on the basis of the experimental results.

Investigation of the effect of diethylene triamine pentaacetic acid chelating agent as an enhanced oil recovery fluid on wettability alteration of sandstone rocks

This study used the diethylene triamine pentaacetic acid(DTPA)-seawater(SW)system to modify the sandstone rock wettability and enhance oil recovery.The investigation involved conducting wettability measurement,Zeta potential measurement,and spontaneous imbibition experiment.The introduction of 5%DTPA-sW solution resulted in a significant decrease in the rock-oil contact angle from 143°to 23,along with a reduction in the Zeta potential from-2.29 mV to-13.06 mV,thereby altering the rock surface charge and shifting its wettability from an oil-wet state to a strongly water-wet state.The presence or absence of potential determining ions(Ca^(2+),Mg^(2+),SO_(4)^(2-))in the solution did not impact the effectiveness of DTPA in changing the rock wettability.However,by tripling the concentration of these ions in the solution,the performance of 5%DTPA-SW solution in changing wettability was impaired.Additionally,spontaneous imbibition tests demonstrated that the 5%DTPA-SW solution led to an increase in oil recovery up to 39.6%.Thus,the optimum mass fraction of DTPA for changing sandstone wettability was determined to be5%.

Influence of pH value and chelating reagent on performance of Li_3V_2(PO_4)3/C cathode material

The Li3V2（PO4）3/C composite cathode material was synthesized via sol-gel method using three different chelating agents （citric acid, salicylic acid and polyacrylic acid） at pH value of 3 or 7. The crystal structure, morphology, specific surface area and electrochemical performance of the prepared samples were investigated by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, cyclic voltammetry （CV）, electrochemical impedance spectroscopy （EIS） and galvanostatic charge/discharge test. The results show that the effects of pH value on the performance of the prepared materials are greatly related to the chelating agents. With salicylic acid or polyacrylic acid as the chelating reagent, the structure, morphology and electrochemical performance of the samples are greatly influenced by the pH values. However, the structure of the materials with citric acid as the chelating agent does not change as pH value changes, and the materials own uniform particle size distribution and good electrochemical performance. It delivers an initial discharge capacity of 113.58 mA·h/g at 10C, remaining as high as 108.48 mA·h/g after 900 cycles, with a capacity retention of 95.51%.

Endodontic irrigants from a comprehensive perspective

This review article explores the fundamental principles of modern endodontics with a focus on root canal cleaning and shaping.It reviews commonly used endodontic irrigant,namely sodium hypochlorite(NaOCl),herbal extracts,chlorhexidine(CHX),and chelating agents,highlighting their properties,applications,and potential drawbacks.NaOCl,a key antimicrobial agent,demonstrates effectiveness against various microorganisms but poses challenges such as high cytotoxicity.Herbal extracts,gaining recognition in endodontics,present an alternative with potential advantages in preserving dentin integrity.CHX,known for its broad-spectrum antimicrobial activity,is discussed in both liquid and gel formulations,emphasizing its role in reducing smear layer formation and preserving hybrid layer durability.Chelating agents,specifically ethylenediaminetetraacetic acid and citric acid,play a vital role in removing the smear layer,enhancing dentin permeability,and facilitating the penetration of antimicrobial agents.The review article underscores the importance of careful application and consideration of each irrigant's properties to ensure safe and effective endodontic procedures.It serves as a valuable guide for clinicians in selecting appropriate irrigants based on specific treatment requirements.

Removal of As and Heavy Metals （Cd, Cu and Pb） in Fine Soil from Soil Washing Process Using Chelating Agent

Fine soil generated from the soil washing process can be the second problem, as contaminants are concentrated in the fine soil, and also took the difficult forms to treat because soluble and exchangeable fractions are already removed by soil washing process; therefore, the fine soil is indicated to hazardous waste, and discarded in hazardous waste landfill. Thus, this research would be performed that arsenic and heavy metals formed difficult to remove in the fine soil were converted to more treatable fractions with chelating agents. Moreover, feasibility study to apply the second remediation targeted to the fine soil inquired. As a result, the chelating agent was decided 50 mM Na2EDTA, and it could develop the complex. In addition, the result of sequential extraction showed that Mn/Fe-oxide fraction, comprised about 28% of amount at first, was decreased about 16%, and organic fraction, consisted approximately 20%, was also decreased about 11%, while exchangeable fraction and carbonate fraction were increased. This result means that the difficult fractions removed could change fractions） by chelating agent. This research can provide the possibility hazardous waste because of difficulty to remediate. the more treatable fractions （exchangeable and carbonate to treat the fine soil, although the fine soil was regarded to

The effect of chelating agent on hydrodesulfurization reaction of ordered mesoporous alumina supported Ni Mo catalysts

In this paper,ordered mesoporous alumina(OMA)support with the high surface area(328 m^(2)g^(-1))and the large pore volume 0.74(cm^(3)·g^(-1))was synthesized by homogeneous precipitation method.And the influence of EDTA on the physical and chemical properties of the modified catalysts was also studied.The characteristic results showed that the addition of EDTA could adjust the metal-support interaction and improved the acidity of the corresponding catalyst.Combined with the catalytic performance results,the EDTA-modified Ni Mo E(1.0)/OMA catalyst displays the highest DBT hydrodesulfurization conversion(97.7%).

Effect of chelating agent on oxidation rate of aniline in ferrous ion activated persulfate system at neutral pH

In the interest of accelerating aniline degradation, Fe2+ and chelated Fe2+ activated persulfate oxidations were investigated in neutral pH condition. Three kinds of chelating agents were selected including citric acid, oxalic acid and ethylenediamine tetraaceatate(EDTA) to maintain available Fe2+. The results indicate that the concentration of chelating agent and ferrous ion didn't follow a linear relationship with the degradation rate of aniline. A 1/1 ratio of chelating agent/Fe2+ results in a higher degradation rate compared to the results by other ratios. The oxidation enhancement factor using oxalic acid was found to be relatively low. In contrast, citric acid is more suitable chelating agent in the ferrous iron activated persulfate system and aniline exhibits a highest degradation with a persulfate/Fe2+/citric acid/aniline molar ratio of 50/25/25/1 compared to other molar ratios.

SYNERGISTIC ACTIVATION OF CHELATING AGENT ON XANTHATE DURING THE FLOTATION OF REFRACTORY COPPER OXIDIZED ORES

For realizing the effective flotation of refractory copper ox-idized ores and developing the activation-flotation theory , the influences of nine different organic chelating agents on xanthate collection pcnver and its adsorption characteristics ivere studied in the flotation of malachite and chrysocolla representatively selected by means of XPS,IR, absorbed quanti-ty measurements and flotation tests.For easily-dissolved malachite flotation , a small amount of chelating agent can obviously enhance xanthate collecting power and make malachite floated easily , and so reduces the consumption of xanthate. For hard-dis-晄olved chrysocolla, chelating agent is able to increase its recovery to 90% , but the chelating agent consumption is high. Chelating agent and xanthate can produce synergistic adsorptions, which follmv Freundlich's adsorption equation on malachite and Chrysocolla surfaces. The high chemical activity of chelating agent and its synergistic activation on xanthate are the key to improving xanthate collection poiver. The synergistic activation of chelat-ing agent on xanthate on melachite surfaces is clearly stronger than on chrysocolla surfaces. According to experimental results, it can be thought that the synergistic activation results from the synergistic complexation of chelating agent and xanthate with copper ions to form biligand-tribasic co-ordination complex.

A NEW BIFUNCTIONAL CHELATING AGENT α,ε-N,N'-BIS(L-CYSTEINYL)-L-LYSINE FOR RADIOLABELLING OF MONOCLONAL ANTIBODIES WITH TECHNETIUM-99M

α,ε-N,N'-bis(L-cysteinyl)-L-lysine was synthesized and char- acterized for the first time.It was then employed as a bifunctional chelating agent to chelate technetium-99m and subsequently conjugated to fragment F(ab')_2 of anti-gastric tumor monoclonal antibody 3G9.The radiolabelled antibody was satisfactorily stable and immunoreactive.

Study on Treatment of Heavy Metals in Fly Ash by a Chelating Agent

The fly ash from two municipal solid waste incineration plants in Shanghai was treated by the self-developed organic composite chelating agent. The results indicated that the stabilization effect of Pb in the fly ash by the composite chelating agent was the best,and the proportions of its easily leaching form in the two kinds of fly ash decreased from 29. 60% and 27. 49% to 3. 05% and 0. 29% respectively. The leaching toxicity of stabilized fly ash was lower than the limits of Standard for Pollution Control on the Landfill Site of Municipal Solid Waste（ GB 16889- 2008）,so it can be landfilled separately in the landfill site of municipal solid waste.