黄原酯棉富集分离金属离子的研究及金属镍中铅和镉的测定

用黄原酯棉对铜、锌、铅、镉、铋、铁、钴、镍等金属离子进行了吸附试验，探索了分离富集条件，给出了５种元素的吸附曲线、脱附曲线和吸附试验结果。作者经过系统的试验，将黄原酯棉用于金属镍及其纯盐类中微量铅、镉的同时分离和测定，获得成功。     

土壤中正丁基黄原酸钾与铅离子的吸附特性研究

通过静态试验研究了土壤对正丁基黄原酸钾的吸附性能和影响因素,以及正丁基黄原酸钾-铅复合污染体系的吸附平衡与动力学特征。结果表明,土壤对正丁基黄原酸钾的吸附过程遵循Lagergren二级动力学模型,等温吸附可用Freundlich模型拟合,提高温度有利于吸附,土壤对正丁基黄原酸钾的吸附属于内扩散控制过程;土壤吸附正丁基黄原酸钾最佳p H范围为5~9,p H较低时正丁基黄原酸钾易被酸解,碱性环境(p H10)将抑制土壤对正丁基黄原酸钾的吸附;正丁基黄原酸钾与Pb2+形成难溶络合物而严重影响了Pb2+在土壤中的吸附,使Pb2+的吸附速率常数由38.319g/(mg·min)提高到70.350g/(mg·min),平衡吸附量(qe)由1.909mg/g降低到1.385mg/g,且影响程度随着Pb2+浓度的升高而减弱。     

Two-dimensional correlation analysis of continuous online in situ ATR-FTIR on the adsorption of butyl xanthate at the surface of a-PbO

The adsorption behavior of butyl xanthate on the surface of lead oxide was investigated using continuous online in situ attenuated total reflectance Fourier transform infrared（ATR-FTIR） spectroscopy technique and two dimensional（2D） correlation analysis.The adsorbed layer studied was prepared by coating α-PbO particles onto the surfaces of the ZnSe crystal.The appearance of spectral peaks at 1203 cm^-1,1033 cm^-1 and their red shift indicated the formation and aggregation of xanthate at the surface of α-PbO.According to 1R intensity changes after rinsing with deionized water and a NaOH solution,the adsorption was proved to be a chemisorption type.The competition between xanthate and OH for the surfaces leads to desorption of xanthate at higher pH.The technique of 2D correlation ATR-FTIR spectroscopy was used to evaluate the changing order of spectral intensities in the adsorption process,and the results indicated that xanthate micelles were formed at the surfaces.The adsorption kinetics of butyl xanthate was found to be a pseudo-second-order reaction model and the adsorption capacity of butyl xanthate at α-PbO was as high as 281 mg g^-1 after 150 min.     

Determination of nickel in biological samples spectrophotometrically involving complexation reaction with some thiazolylazo compounds

Three new heterocyclic azo compounds, 5(2-benzothiazolylazo)2,2 biphenyldiol (I), 5-(2-benzothiazolylazo)-8-hydroxyquinolene (II) and 4-(2-benzothiazo-lylazo)3-hydroxy-2-naphthoic acid (III) were synthesized. The formation constant of the reagents in 30% (v/v) ethanol and reactions with various metal ions were studied. These reagents (I-III) reacts with nickel ion to form (2:1) colored complex with an absorption band at 604, 635 and 643 nm. The apparent stability constants and the optimum conditions for complete color development were investigated. Beer's law is obeyed over the concentration ranges of 0.05-3.50, 0.05-4.00 and 0.05-3.10 micrograms ml-1. For more accurate analyses, Ringbom optimum concentration ranges were found to be 0.20-3.25, 0.20-3.80 and 0.20-2.90 micrograms ml-1 using reagents I, II and III, respectively. The apparent molar absorptivity and Sandell sensitivity were also calculated. The interference of various foreign ions on the determination of nickel was investigated. The proposed method has been successfully applied to the determination of nickel substrates in various biological samples.     

Cryo‐XPS study of xanthate adsorption on pyrite

The adsorption of xanthate on pyrite has been extensively studied. However, the adsorption mechanisms remain a subject of controversy. Formation of both dixanthogen and metal‐xanthate complexes has been suggested. In this study, both room temperature X‐ray photoelectron spectroscopy (XPS) (RT‐XPS) and liquid nitrogen temperature XPS (Cryo‐XPS) were used to study interactions between pyrite and xanthate. While dixanthogen was not detected by RT‐XPS, it was successfully identified through C1s and S 2p peaks using Cryo‐XPS. The impact of pH and copper activation on adsorption of xanthate on pyrite was also investigated. It was found that at low pH, dixanthogen is the dominant species of xanthate adsorption on pyrite. At high pH, metal‐xanthate complexes were found to be prevalent on pyrite surfaces, which are responsible for the surface hydrophobicity. Copper activation showed a significant effect on xanthate adsorption on Cu‐activated pyrite, resulting in mostly the formation of Cu‐xanthate complexes rather than dixanthogen, mainly in the form of Cu(I)‐isopropyl xanthate complex (CuIPX). Copyright © 2012 John Wiley & Sons, Ltd.     

Mechanism of antioxidant action. Transformation involved in the antioxidant function of nickel dithiolates—2

The initial transformation products from nickel dialkyl dithiophosphates and nickel alkyl xanthates have been identified by spectrophotometric and kinetic methods. A common mechanism of action is involved for both nickel complexes and the distribution of products from complexes during their reaction with hydroperoxides suggests a greater contribution from an ionic mechanism in the case of dithiophosphate. Nickel dialkyl dithiophosphate is more stable to u.v. light than nickel alkyl xanthate and its reaction with tert. butyl hydroperoxide in the presence and absence of light is 7–8 times faster than that of the xanthate.     

The metal complexes of some azo and azomethine dyestuffs : Determination of stability constants,and preparation of solid complexes

The stability constants of the complexes of 4-(2-pyridylazo)-resorcinol (I) with copper(II), cobalt-(II), zinc(Il), lead(ll), and uranium(VI) were determined by potentiometric titration in aqueous media, and were shown to have very high values, the stability constant of the copper(ll) complex approaching that of the copper(ll)-EDTA complex. The nickel(II) complex was shown to behave anomalously. The stability constants were also determined by this method in 1:1 dioxan/water, and the values obtained compared with those for the complexes of salicylidene-2-aminopyridine (II), 2-(o-hydroxy-phenyl-imino-methyl)-pyridine(III), and benzeneazoresorcino (IV). It is shown that chelation by (1) is terdentate, involving the pyridine nitrogen, the o-hydroxyl group and the azo nitrogen farthest from the heterocycle.The solid copper(II) complexes of these four ligands were prepared; in the solid complexes the azo nitrogen nearest the heterocycle plays a greater part than in the complexes in solution.     

丁基黄药在CuO表面吸附的二维连续在线原位ATR-FTIR光谱研究

运用连续在线原位衰减全反射傅里叶变换红外光谱(ATR-FTIR)技术测定了纳米CuO表面对丁基黄药的吸附行为. 在FTIR 谱图中发现有峰的红移现象,吸收峰由1200 cm^-1偏移到1193 cm^-1,用超纯去离子水脱附,峰强度只有微小的变化,可判断丁基黄药在CuO表面发生了很强的化学吸附. 通过对吸附行为进行二维(2D)红外光谱分析,分辨出吸附过程中光谱强度的变化顺序. 二维异步相关光谱测定结果表明,1265 cm^-1处振动吸收峰最先引起光谱强度的变化,1265 cm^-1处吸收峰可归因为表面反应生成的双黄药和黄药分子聚集体的复合峰. 根据1200 cm^-1处黄药特征吸收峰强度的变化,进行吸附动力学模拟,得出CuO对丁基黄药的最大吸附量为529 mg·g^-1,且吸附符合拟二级吸附动力学过程.     

Copper(II), nickel(II), cobalt(II) and zinc(II) complexes of 2-[2-(6-methylbenzothiazolyl)azo]-5-dimethylaminobenzoic acid: synthesis,spectral, thermal and molecular modelling studies

Complexes of copper(II), nickel(II), cobalt(II), and zinc(II) with 2-[2-(6-methylbenzothiazolyl)azo]-5-dimethylaminobenzoic acid have been prepared and characterized by elemental analysis, vibrational spectra, magnetic susceptibility measurements, conductance measurements and e.p.r. spectra. Stability constants have been evaluated potentiometrically. Electronic spectra, magnetic susceptibility measurements and molecular modeling studies support a distorted square planar geometry around the metal ions. Vibrational spectra indicate the coordination of the azo group, nitrogen of benzothiazole, the carboxylate anion and the acetate ion on complexation with the metal ion. All complexes are found to be monomers. The stability of the complexes follow the order: copper(II) > nickel(II) > cobalt(II) > zinc(II).     

Evaluation of stability constants of metal complexes with sulphonated azo-ligands

An ion-exchange procedure is described for the determination of the stability constants for cadmium, copper, nickel and manganese complexes with three sulphonated azo ligands: calmagite, alizarin violet N and palatine chrome black. The results, log K values, show a good agreement with those obtained by a spectrophotometric technique.     

Surface stoichiometry of zinc sulfide and its effect on the adsorption behaviors of xanthate

ABSTRACT: In this paper, the surface stoichiometry, acid-base properties as well as the adsorption of xanthate at ZnS surfaces were studied by means of potentiometric titration, adsorption and solution speciation modeling. The surface proton binding site was determined by using Gran plot to evaluate the potentiometric titration data. Testing results implied that for stoichiometric surfaces of zinc sulfide, the proton and hydroxide determine the surface charge. For the nonstoichiometric surfaces, the surface charge is controlled by proton, hydroxide, zinc and sulfide ions depending on specific conditions. The xanthate adsorption decreases with increasing solution pH, which indicates an ion exchange reaction at the surfaces. Based on experimental results, the surface protonation, deprotonation, stoichiometry and xanthate adsorption mechanism were discussed.     

New aspects of the electroadsorption of ethyl xanthate on copper electrodes

The interaction of the ethyl xanthate (EX) anion with a copper electrode in a borate buffer solution, pH 9.2, has been investigated by cyclic voltammetry (CV), electrochemical quartz crystal microbalance (EQCM), electrochemical impedance spectroscopy (EIS), and measurements of contact angle (CA) under controlled potential. The results obtained allow establishing that, in the potential range from -0.80 and -0.60 V, two parallel reactions were characterized. These reactions were the ethyl xanthate electroadsorption and the hydrogen evolution reaction (HER). This last reaction has not been described by previous authors. Besides, the EIS measurements show that the mechanism of the HER on copper electrodes is not affected by the presence of a ethyl xanthate species. The EQCM study shows that in the electrodesorption process the departure of each ethyl xanthate species from the copper electrode is accompanied with the simultaneous entry of four to five water molecules. This fact is in accordance with the number of copper atoms involved in the adsorption of one ethyl xanthate species.     

连续在线原位ATR-FTIR技术测定介孔CuAl2O4对黄药的吸附

以丁胺和正十二醇为混合模板剂, 采用共沉淀法制备了介孔纳米CuAl₂O₄. 用X射线粉末衍射(XRD)、傅里叶变换红外(FTIR)光谱、N₂吸附-脱附对产物的结构进行了表征. 采用连续在线原位衰减全反射傅里叶变换红外(ATR-FTIR)光谱技术研究了水溶液中丁基和辛基黄药在介孔CuAl₂O₄表面的吸附. 随着吸附时间的延长,1200 和1040 cm^-1两处黄药特征峰的高度逐渐增加, 根据1200 cm^-1处C-O-C伸缩振动峰的变化来评价黄药在CuAl₂O₄表面的吸附动力学过程. 结果表明, 介孔纳米CuAl₂O₄对黄药有很强的吸附能力, 在100 min 的时间内, CuAl₂O₄样品对丁基和辛基黄药的吸附量分别达到了236 和300 mg·g^-1, 且属于化学吸附. 对实验数据进行理论模拟, 发现吸附过程更接近于拟二级吸附动力学方程.     

Temperature effect on xanthate sorption by chalcopyrite

Xanthate ions sorption on copper ore (chalcopyrite) is studied as a function of temperature (273-293 K) in the pH range (8-11). The sorption of xanthate ions at all the pH values is observed to increase with the increase in temperature. The changes in pH, dissolution studies of the ore, SO2(4)- concentration determinations, and FTIR studies were employed to probe the mechanism of the process of adsorption. The results are found to fit successfully to the linear form of the Freundlich equation. The isosteric heats of adsorption (DeltaHi) are also calculated and show that the adsorption of xanthate on copper ore under the given experimental condition is endothermic in nature. The values of DeltaHi found are in conformity with the ion exchange sorption of xanthate by the chalcopyrite.     

New chromogens of the ferroin-type-I. Substituted triazines related to 6-cyano-2,2'-bipyridine

A spectrophotometric study has been made of the iron(II), cobalt(II), nickel(II) and copper(I) chelates of seven new compounds that contain the ferroin functional grouping. None of the new compounds proved to be superior to chromogenic reagents currently in use, but the results are of interest in designing new chromogens.     

沉淀溶解法制备纳米硫化锌

以烷基黄原酸锌和硫化钠分别为锌源和硫源，采用烷基黄原酸锌沉淀溶解法制备了粒度可调、粒径分布比较窄的面心硫化锌纳米粒子，利用比表面积(BET)测定、透射电镜(TEM)、粉末X射线衍射(XRD)、傅里叶转换红外光谱(FTIR)等方法对合成的硫化锌纳米粒子进行了表征。结果表明随着烷基黄原酸锌链长的增长，通过添加硫化钠而生成的硫化锌纳米粒子的粒径逐渐减小。本文还对沉淀溶解法制备纳米硫化锌的溶液化学反应机理进行了探讨。     

Exploring Alkylated Ferrocene Sulfonates as Electrocatalysts for Sulfide Detection

Alkylated ferrocene sulfonate compounds, 1,1′‐dimethyl ferrocene sulfonate, t‐butyl ferrocene sulfonate, ethyl ferrocene sulfonate, and n‐butyl ferrocene sulfonate are explored for the electrocatalytic detection of sulfide at a boron‐doped diamond electrode. Voltammetric interrogation of the ferrocene sulfonate compounds is investigated to determine oxidizing potentials, diffusion coefficients and responses towards sulfide. In the latter case, measurement of the electrocatalytic rate constants by means of chronoamperometry indicates a high electrocatalytic activity (ca. 10³ M^?1 s^?1) towards sulfide.     

Ternary surface complexes in silica-Ni2+ ions-2,2′-dipyridyl systems

The adsorption of complexes of nickel ions with an organic base (2,2′-dipyridyl) at an interface between silica and an aqueous electrolyte solution has been considered in terms of the theory of complexation. It has been shown that, on the silica surface, ternary complexes are formed, in which nickel ions are bonded to silanol groups. The equilibrium constants of the reactions of ternary surface complex formation have been calculated from the adsorption curves describing the pH dependences of nickel ion and dipyridyl adsorption.     

Oxidation of magnesium with cyclopentadienyl(triphenylphosphine)nickel chloride in aprotic solvents

The products of magnesium oxidation with cyclopentadienyl(triphenylphosphine)nickel chloride were revealed. Effective equilibrium constants of adsorption of the reagents on the metal surface, entropy and enthalpy of these processes, rate constants, and activation energy were determined. A probable scheme of the process is assumed.     

Electrophoretic Mobility Study of the Adsorption of Alkyl Xanthate Ions on Galena and Sphalerite

The adsorption of ethyl and amyl xanthate ions on galena and sphalerite fines has been studied using electrophoretic light-scattering (ELS) measurements. It was performed on galena and sphalerite (<2&mgr;m) in aqueous solution at different potassium ethyl xanthate (PEX) and potassium amyl xanthate (PAX) concentrations. It has been observed that the presence of PEX or PAX caused the isoelectric points (IEP) of galena and sphalerite fines to shift and the electrophoretic mobility to reverse in sign, indicating that the xanthate ions chemisorbed on galena and sphalerite surfaces. This adsorption markedly broadened the electrophoretic mobility distribution of the mineral fines, suggesting that the populations of the particles have quite different adsorption densities of xanthate ions, and therefore the particle hydrophobicity was different. This phenomenon might be attributable to the effect of the hemimicelle adsorption of the xanthate ions on the minerals, the nonuniform distribution of active sites and their degree of activity, the effect of particle size and shape, etc. The nonuniform adsorption has been found to increase with increasing PEX or PAX concentration, reaching a maximum at a medium concentration followed by a decline. Also, experimental results have demonstrated that the nonuniform adsorption of the xanthate ions is much stronger on sphalerite than on galena, which may explain why sphalerite has a worse flotation response than galena when alkyl xanthates are used as collectors in flotation systems. Copyright 2001 Academic Press.