亚硫酸氢钠溶液稳定性的探讨

从溶液的酸度、空气及光照、温度等因素对亚硫酸氢钠溶液的稳定性及滴定反应进行实验探讨,选择三乙醇胺(TEA)、甲醛、二乙胺四乙酸二钠(EDTA-2Na)、盐酸羟胺四种常用的螯合剂或强还原剂进行试验,结果表明EDTA-2Na作为溶液的稳定剂效果最好,其次是甲醛,最后是盐酸羟胺。TEA因为其强碱性会降低溶液的稳定性而不宜作为稳定剂。

抗凝剂对抗-HIV酶联免疫吸附试验实验检测结果的影响

目的探讨二乙胺四乙酸钠盐(EDTA-Na2)抗凝剂对抗-HIV酶联免疫吸附试验实验(ELISA)检测结果的影响。方法严格依照抗-HIV试剂盒操作说明要求,应用AT-plus2全自动加样器和FAME全自动酶免处理系统分别检测90例符合献血条件的献血者抗凝血浆和血清标本180份,通过酶标仪读板OD数值并将结果进行分析。结果当血液与EDTA-Na2抗凝剂的比例为1∶4以上时,可以基本消除抗凝剂对结果的影响,同标本类型不同试剂间OD数值数据,差别无显著性意义(P>0.05),相同试剂不同标本类型间OD数值数据,差别有显著性意义(P<0.05)。结论应充分估量采集标本中抗凝剂对抗-HIVELISA实验结果的影响因素,尽量减低由于标本的不正确采集和保存而造成对检测结果的影响,确保血液检测质量安全。

Effect of EDTA and NH_4Cl additives on electrodeposition of Zn-Ni films from choline chloride-based ionic liquid

Two additives of ethylene diamine tetraacetic acid （EDTA） and ammonium chloride （NH4C1） were separately used in the electrodeposition of Zn-Ni alloy films from a deep eutectic solvent. The effects of these two additives on electrodeposition behavior, composition, morphology, and corrosion performance of the Zn-Ni alloys were investigated. The electrodeposition behaviors of Zn-Ni alloy revealed by the cyclic voltammetry show that the addition of EDTA to the Zn-Ni electrolyte enhances the Zn incorporation into the alloy film while the addition of NH4C1 produces an opposite effect by suppressing Zn incorporation into the film. With an increase of EDTA concentration in the electrolyte, the Zn content of the Zn-Ni films increases, while the grain size of the deposits and the current efficiency of the plating process decrease. The increase of NH4C1 concentration in the electrolyte would significantly refine the grain size of the electrodeposited Zn-Ni films, reduce the Zn content and increase the cathodic current efficiency. The corrosion testing indicates that the barrier corrosion resistances of Zn-Ni films electrodeposited from NHnC1 containing electrolytes are superior to those electrodeposited from EDTA-containing electrolytes, which in turn are superior to those electrodeposited from additive-free electrolytes.

A Novel Enhancer for Fe^(2+)-Catalyzed Light Emission Reaction of Luminol and Dissolved Oxygen

EDTA was used as an enhancer for Fe 2+ catalyzed light emission from luminol oxidation by dissolved oxygen. As a result, the limit of detection for ferrous ion with flow injection analysis was improved by a factor of 160 by addition of EDTA to the luminol solution. Fe 2+ and Fe 3+ were determined simultaneously with a novel copper-coated zinc reductor minicolumn installed in one of the shunt after sample splitting in the manifold. The reductor minicolumn can be used for 3000 determinations at least. The dynamic range of determination was 1×10 -9 ～1×10 -5 mol·L -1 , with the limit of detection of 2.7×10 10 and 3.5×10 10 mol·L 1 ,for Fe 2+ and Fe 3+ , respectively. The preci sion for determination of 2×10 7 mol·L 1 of Fe 2+ and Fe 3+ was 2.3% and 4.0% (n=8), respectively, at a sampling rate of 60 h -1 . Cr 3+ and Co 2+ interfere. Fe 2+ and Fe 3+ in mixture were determined with satisfactory results. Samples of Fe 2+ and Fe 3+ were determined simultaneously and the results in good agreement with the standard spectrophotometric method. Indications were shown that EDTA functions as an enhancer, Fe 2+ as a catalyst, and oxygen is the oxidant of the chemiluminescent reaction, and the mechanism of the reaction was discussed.

External surface modification of as-made ZSM-5 and their catalytic performance in the methanol to propylene reaction

Post-synthetic treatment of high-silica as-made ZSM-5 with organic template in the micropores was explored to reduce/remove the external surface acid density of ZSM-5. It is found that Na_2H_2 EDTA treatment can selectively remove the surface Al atoms, but generates new acid sites（likely silanol nests） on the external surface. H_3PO_4 treatment is unable to remove surface Al atoms, while small amount of P is left on the external surface, which effectively decreases the acid density. The catalytic performance of the resultant materials is evaluated in the methanol conversion reaction. H_3PO_4 treatment can effectively improve both the catalytic lifetime and the stability of propene selectivity.This occurs due to a combination of the increased tolerance to the external coke deposition and the depressed coking rate（reduced side reactions）. Na_2H_2 EDTA treatment only prolongs the catalytic lifetime, resulting from the improved tolerance to the external coke deposition. Under the optimized H_3PO_4 treatment condition, the resultant ZSM-5 gives a catalytic lifetime of about 1.5 times longer than the precursor. Moreover, the propene selectivity is improved, showing a slight increasing trend until the deactivation.

Extraction of metals from a zinc smelting slag using two-step procedure combining acid and ethylene diaminetetraacetic acid disodium

A two-step leaching method in combination of acid and ethylene diaminetetraacetic acid disodium （EDTA-Na2） was applied to extract metals such as Cd, Cu, Fe, Pb and Zn from a zinc smelting slag. The results show that the extraction rates of Cd, Cu, Fe and Zn in slag reach 88.3%, 54.1%, 69.6% and 54.7%, respectively, while the extraction rate of Pb is only 0.05% leached with 1.25 mol/L sulfuric acid under the conditions of the ratio of slag to liquid of 100 g/L, 65 ℃ and 120 r/min for 2 h. However, Pb extraction rate from 1.25 mol/L sulfuric acid leached residue reaches as high as 66.5% by using 0.1 mol/L EDTA-Na2 solution. The results indicate that two-step sequential extraction procedure combining 1.25 mol/L sulfuric acid and 0.1 mol/L EDTA-Na2 solution can extensively extract Cd, Cu, Fe, Pb and Zn from zinc smelting slag.

Direct hydrothermal synthesis of Mo-containing MFI zeolites using Mo-EDTA complex and their catalytic application in cyclohexene epoxidation

A series of Mo-containing MFI zeolites with different Mo loadings(Mo-MFI-n,n represent the initial Si/Mo molar ratio)was hydrothermally synthesized by using tetrapropylammonium hydroxide as the template and Mo-EDTA complex as the Mo source.Various characterization results demonstrated that the use of the Mo-EDTA complex is beneficial for the incorporation of more Mo species into the MFI-type zeolites.The special complexing capability of EDTA^(2–)plays a critical role in adjusting the release rate of the Mo species to combine with the Si tetrahedron species during the zeolite growth process,thus leading to a uniform distribution of Mo in the MFI framework.In addition,a small portion of extra-framework Mo clusters may be distributed inside the channels or near the pore window of the zeolites.The catalytic properties of these Mo-containing MFI zeolites were evaluated for the epoxidation of cyclohexene with H_(2)O_(2)as the oxidant.The composition-optimized catalyst,Mo-MFI-50,efficiently converted cyclohexene to the corresponding epoxide with a relatively high conversion(93%)and epoxide selectivity(82%)at 75℃after 9 h of reaction.Moreover,the resultant Mo-containing MFI catalyst exhibited excellent structural stability and recoverability and was easily recycled by simple filtration without the need for calcination treatment.

Effect of Additive EDTA on Crystallization Process of Magnesium Hydroxide Precipitation

The effects of additive ethylenediaminetetraacetic acid (EDTA) on crystallization process were investigated by the induction time of MgSO 4-NaOH system. Nucleation and growth rates, growth mechanism and particle size distribution of magnesium hydroxide precipitation were involved with. The induction time in unseeded and seeded precipitation of magnesium hydroxide with and without additive EDTA was measured. The conductivity method was used to determine the induction period. Theoretical relations of the induction time and supersaturation ratio for different growth mechanisms and a combined analysis on the induction time were applied to determine nucleation and growth rates. The growth mechanism of magnesium hydroxide precipitation was disclosed by analyzing the experimental data with and without additive. The analysis on induction time indicated that additive EDTA had a significant influence on both nucleation and growth of magnesium hydroxide precipitation. The mechanism underlying the effect of EDTA on crystal growth was 2-dimension nucleation-mediated growth model.

Synthesis and Characterization of Ethylenediamine Tetraacetic Acid Tetrasodium Salt Loaded in Microcapsules with Slow Release Properties

The microcapsules with cores of ethylenediamine tetraacetic acid tetrasodium salt(Na4-EDTA)and walls of polyurea were synthesized via an interfacial polycondensation reaction with 2,4-tolylene diisocyanate as an oil-soluble monomer and diethyl triamine as a water-soluble monomer.Various manufacturing parameters,including the amount of emulsifier,agitation speed,stirring time and ratios of the wall materials to core materials,were altered to optimize process variables during the synthesis of microcapsules,and the effects of these parameters on the characteristics of the microcapsules were examined.The structure,morphology,mean particle size and size distribution were characterized by optical microscope and scanning electron microscopy(SEM),showing that the mean diameter of optimal microspheres was approximately 6μm,and microcapsules were spherical.In vitro release of Na4-EDTA from these microcapsules was performed in distilled water.Under the optimal preparation conditions, the Na4-EDTA release profiles were biphasic with a burst release followed by a gradual release phase.After an initial burst,a continuous Na4-EDTA release was up to 5-7 days.The optimal synthesis conditions for the microcapsules with stable,good morphology and good controlled-release properties were as follows:emulsifier Span-80 10% (by mass),agitation speed 900 r·min1,stirring time 30 min,and the ratio of the wall materials to core materials 0.15.

Quick valence analysis method of vanadium toward accurate toxicity assessment of vanadium-containing hazardous wastes

In order to develop a quick, efficient and sensitive valence analysis method of vanadium(Ⅴ), the highperformance liquid chromatography(HPLC) was utilized to separate and quantify EDTA-complexed Ⅴ(Ⅲ), Ⅴ(Ⅳ) and Ⅴ(Ⅴ) ions. The influence of EDTA, TBAOH, solution pH and organic modifier on retention behavior of V-EDTA complexes was investigated. Complexed Ⅴ(Ⅲ), Ⅴ(Ⅳ) and Ⅴ(Ⅴ) ions can be separated and quantified in 5 min, with detection limits of 0.04 mg/L Ⅴ(Ⅲ), 0.07 mg/L Ⅴ(Ⅳ), and 0.06 mg/L Ⅴ(Ⅴ), respecti vely. The established method is applied to analyzing the hazardous waste of V-Cr-bearing reducing slag and results demonstrate 49.94% of its Ⅴ element to be toxic Ⅴ(Ⅴ). This work opens a new avenue for quick and accurate toxicity assessment of hazardous wastes containing multivalent heavy metals.

Morphologies of hydroxyapatite nanoparticles adjusted by organic additives in hydrothermal synthesis

Properties of hydroxyapatite （HA, Ca10（PO4）6（OH）2）, including bioactivity, biocompatibility, solubility and adsorption could be tailored over wide ranges by the control of particle composition, particle size and morphology. In order to satisfy various applications, well-crystallized pure HA nanoparticles were synthesized at moderate temperatures by hydrotherrnal synthesis, and HA nanoparticles with different lengths were obtained by adding organic additives. X-ray diffractometry （XRD） and Fourier transform infrared （FTIR） spectrometry were used to characterize these nanoparticles, and the morphologies of the HA particles were observed by transmission electron microscopy （TEM）. The results demonstrate that shorter rod-like HA particles can be prepared by adding cetyltrimethylammonium bromide （CTAB）, as the additive of CTAB can block the HA crystal growth along with c-axis. And whisker HA particles are obtained by adding ethylenediamine tetraacetic acid （EDTA）, since EDTA may have effect on the dissolution-repreeipitation process of HA.

Effects of iron electrovalence and species on growth and astaxanthin production of Haematococcus pluvialis

To increase the cell concentration and the accumulation of astaxanthin in the cultivation of Haematococcus pluvialis, effects of different iron electrovalencies （Fe^2＋-EDTA and Fe^3＋-EDTA） and species （Fe-EDTA, Fe（OH）x^32x and FeC6H5O7） addition on cell growth and accumulation of astaxanthin were studied. Results show that different iron electrovalencies have various effects on cell growth and astaxanthin accumulation of H. pluvialis. Compared with Fe^3＋-EDTA, Fe^2＋-EDTA stimulate more effectively the formation of astaxanthin. The maximum astaxanthin content （30.70 mg/g biomass cell） was obtained under conditions of 18 μmol/L Fe^2＋-EDTA, despite the lower cell density （2.3×10^5 cell/ml） in such condition. Fe^3＋-EDTA is more effective than Fe^2＋-EDTA in improving the cell growth. Especially, the maximal steady-state cell density, 2.9×10^5 cell/ml was obtained at 18 μmol/L Fe^3＋-EDTA addition. On the other hand, all the various species of iron （EDTA-Fe, Fe（OH）x^32x, FeC6H5O7） are capable to improve the growth of the algae and astaxanthin production. Among the three iron species, FeC6H5O7 performed the best. Under the condition of a higher concentration （36 μmol/L） of FeC6H5O7, the cell density and astaxanthin production is 2 and 7 times higher than those of iron-limited group, respectively. The present study demonstrates that the effects of the stimulation with different iron species increased in the order of FeC6H5O7, Fe（OH）x^32x and EDTA-Fe.

Zinc extraction from sewage sludge with [S,S]-EDDS

An environmentally friendly biodegradable chelant,[S,S]-ethylenediaminedisuccinic acid(EDDS),was used to separate heavy metals from sewage sludge based on chemical extraction technology.The extraction of zinc from sewage sludge with an aqueous solution of EDDS was studied under various conditions.It is found that the extraction efficiency of zinc using EDDS is equivalent to that using ethylenediaminetetraacetic acid(EDTA)at the molar ratio of chelant to total heavy metals of 1:1 over pH range of 5-9.EDDS is capable of extracting zinc from the sludge.The extraction efficiency is improved obviously and reaches a higher value within pH range from 3 to 10.The extraction efficiency maintains at about 65% when pH≥4.5 and the ratio of 10:1.By comparing the species contents of the zinc in sewage sludge before and after the extraction,it is found that the extracted zinc mainly comes from the acid soluble,reducible and oxidizable fractions.

Flue gas desulphurization using sodium sulfide on pilot scale

A novel technique of flue gas desulphufization （FGD） using industrial sodium sulfide as absorbent is described to remove SO2 in flue gas. The FGD byproduct in this novel technique is sodium thiosuffate （Na2S2O3 · 5H2O, Hypo） which can be used as chemical raw material. Optimal operating parameters about this technique have been determined. In order to enhance productive efficiency of sodium thiosulfate, EDTA disodium additive is added into absorption solution to prevent oxidation of sodium thiosulfate. Its optimal concentration is 0. 02 wt. %. The pH value of absorption solution is set in the range of 5 ~ 6.5. Experimental results show that SO2removal efficiency averagely reach 98.72 %. The highest productive efficiency of sodium thiosulfate reaches 83.24 %. The sodium thiosulfate formed during FGD can be separated from saturated absorbent by filtration, concentration and crystallization. The filtrate after separating sodium thiosulfate will be reused as SO2 absorbent by replenishing some fresh sodium sulfide.

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

Isolation and characterization of venom from nematocysts of jellyfish Rhopilema esculentum Kishinouye

The present work is the first report of the biochemical characterization of the venom from nematocysts of the jellyfish Rhopilema esculentum Kishinouye. The nematocysts were isolated by autolysis and centrifugation and separated by flow cytometry. Four types of nematocysts were identified： mastigophores, euryteles, and atrichous and holotrichous isorhiza. SDS-PAGE and amino acid analyses demonstrated that most of the proteins in the nematocyst extract were between 10 kDa and 40 kDa, and that glutamic acid was the main amino acid. A hemolytic activity assay showed that the activity of the nematocyst venom （RNV） was strongest in Tris-HCl buffer （50 mmol/L, pH 7.8, 5% glycerol, 0.5 mmol/L EDTA, 0.1 mol/L NaC1）. The hemolytic activity was related to protein concentration and the HU50 against chicken erythrocytes was 0.91 μg/mL.

Structure and magnetic behavior of a trinuclear Mn(Ⅱ)coordination complex with EDTA-ligand

A trinudear Mn（II） coordination complex Mna （HEDTA）2-10H20 （EDTA=ethylene diamine tetraacetic acid） 1 has been synthesized and characterized by X-ray crystal structure determination. In addition, IR spectrum, thermogravimetric analysis, electron paramagnetic resonance （EPR） spectra and magnetic susceptibility of this complex are discussed. X-ray determination indicates that six- and seven-coordinate modes between Mn（Yl） and H4EDTA exist alternately in 1. Furthermore, detailed discussion of magnetic ordering in tile temperature range of 2-300 K reveals the antiferromagnetic interactions in the complex.

Defluorination of Wet-Phosphoric Acid： Equilibrium and Kinetic Studies

This study describes the advantages of using iron-oxide-pillared MF （montmorillonite） and EDTA （ethylenediaminetetraacetic acid）-pillared MD （montmorillonite） for the removal of fluoride in the phosphoric acid. The MF and MD were characterized by using BET （Brunauer-Emmett-Teller） and SEM （scanning electron microscope） for there to appreciate their textural and structural properties and in order to appraise their capacity in the fixation of the fluorine experimental results of fluorine adsorption show a defluoration of the phosphoric acid passing beyond 90% with both clays with a light performance for the MD. The kinetics of fluorine adsorption on MF and on MD has been measured at different temperatures. Indeed, the adsorbed quantity increases more favorably to temperatures more high. This kinetics could be described by two models： pseudo-first-order or pseudo-second-order, which depends on temperature and the nature of adsorbent. At different temperatures used and with various adsorbents （MD and MF, the pseudo second order model was the most reliable to determine the order of kinetics of adsorption of fluorine, which is also reflected a good correlation coefficient （above 0.99）. The fluoride sorption was reasonably explained with Langmuir or Freundlich isotherms. Thermodynamic parameters such as AG~, AH~, AS~ and kinetic one E,, （apparent activation energy） were calculated in order to understand the nature of sorption process. Results indicate that the mechanism of adsorption of the ion of fluoride on the pillared montmorillonite is an exothermic reaction. During equilibrium conditions, both the systems showed negative Gibbs energy, which indicates stability of system. The values of apparent activation energy for the both clays show that the adsorption of F ions is easier on the MF.

Synthesis and Crystal Structure of Potassium Triethylenetetraaminehexaacetatodi [Oxo-vanadium(Ⅳ)] Hexahydrate, K_2[V_2O_2(ttha)]·6(H_2O)

The title complex, potassium triethylenetetraaminehexaacetatodi [oxo-vanadium (Ⅳ)] hexahydrate K2[V2O2(ttha)]6(H2O), was synthesized in aqueous solution and its crystal structure has been determined by X-ray diffraction. The complex belongs to a triclinic system, space group P?with a = 6.645(1), b = 9.870(2), c = 13.263(3) ? a = 70.68(3), b = 76.27(3), g = 71.66(3), V = 770.5(3) 3, Mr = 808.58, Dc = 1.743 g/cm3, Z = 1, m = 0.968 mm-1, l(MoKa) = 0.71073 and F(000) = 416. The final R = 0.0465 and wR = 0.1091 for 2974 observed diffractions with I ≥ 2s(I). In the complex, the V atom is octahedrally coordinated to the oxo ligand, two N and three O atoms of the triethylenetetraaminehexaacetic (TTHA) ligand. All of the ten chelating sites are coordinated to the two vanadium atoms, and the coordination octahedron is distorted. Each [V2O2(ttha)]2- ion is further connected by the K+ ions through carboxyl groups of TTHA6- ion, forming a two dimensional network structure.