钠改型蛭石的铵离子交换平衡

对经NaCI处理的钠型蛭石在不同pH和温度条件下进行了铵离子交换性能的研究.结果表明,交换反应在前60min速率最快,约120min就趋向于平衡2铵离子交换总量随pH变化而波动,在pH=7,点上取最大值为92.85mmol/100g2铵离子交换量和交换选择性随温度的降低而显著升高.     

Decationization and dealumination of clinoptilolite tuff and ammonium exchange on acid-modified tuff

The paper presents results of investigation of exchange of the clinoptilolite tuff cations with hydrogen ions from HCl solution of concentration 0.1 mmol cm(-3) and ammonium ions solutions of concentrations 0.0071 to 2.6 mmol cm(-3). Molal concentrations, x (mmol g(-1)) of cations exchanged in acid solution and in ammonium ions solutions were compared with molal concentrations of cations obtained by determination of the cation-exchange capacity of clinoptilolite tuff. The obtained results show that at ammonium ion concentrations lower than 0.1 mmol cm(-3), with regard to exchange capacity for particular ions, best exchanged are Na+ ions, followed by Mg2+ and Ca2+ ions, while exchange of K+ ions is the poorest (Na+ > Mg2+ > Ca2+ > K+). At ammonium concentrations from 0.2 to 1 mmol cm(-3) the order is Na+ > Ca2+ > Mg2+ > K+. At concentrations higher than 1 mmol cm(-3) the order is Na+ > Ca2+ > K+ > Mg2+. The results are a consequence of the uptake of hydrogen ions by zeolite samples in ammonium ions solutions at concentrations lower than 1 mmol cm(-3) and indicate the importance of Mg2+ (besides Na+ ions) for the exchange between clinoptilolite cations and H+ ions, in contrast to K+ ions, whose participation in the reaction with H+ ions is the lowest. During decationization of the clinoptilolite in acid solution, best exchanged are Na+, Mg2+, and Ca2+ ions, while exchange of K+ ions is the poorest. Due to poor exchange of K+ and H+ ions and good exchange of Na+, Mg2+, and Ca2+ ions, it is to be assumed that preservation of stability of the clinoptilolite structure is caused by K+ ions present in the channel C. Clinoptilolite is dissolved in the clinoptilolite A and B channels where Na+, Mg2+, and Ca2+ ions are present. On the acid-modified clinoptilolite samples, exchange of ammonium ions is poorer than on natural zeolite. The longer the contact time of the zeolite and acid solution, the worse ammonium ions exchange. It can be assumed that H+ ions exchanged with zeolite cations are consumed for solution of aluminum in the clinoptilolite structure; therefore the concentration of H+ ions as exchangeable cations decreases. In the ammonium ion solution at a concentration of 0.0065 mmol cm(-3), from the acid-modified zeolite samples, Al3+ ions are exchanged best, followed by Na+, Mg2+, Ca2+, and K+ ions. Further to the results, it is to be assumed that exchangeable Al3+ ions available from clinoptilolite dissolution are best exchanged with H+ ions in acid solution.     

Simultaneous removal of ammonium and phosphate by zeolite synthesized from fly ash as influenced by salt treatment

To develop an effective technique for enhancing the removal efficiency of ammonium and phosphate at low concentrations without losing potential removal capacity, Na-ZFA (zeolite synthesized from fly ash) was converted into Ca-, Mg-, Al-, and Fe-ZFA by salt treatment and the simultaneous removal of ammonium and phosphate by ZFA saturated with different cations was investigated. It was shown that Al3+-ZFA had the highest removal efficiencies (80-98%) for ammonium, followed by Mg2+ (43-58%), Ca2+ (40-54%), Na+ (<20%), and Fe3+ (<1%). Both alkaline pH values (in the cases of Na+, Ca2+, Mg2+) and acidic pH value (in the case of Fe3+) inhibited the sequestration of ammonium. At low initial phosphate concentrations, the efficiency of phosphate removal by Al3+- and Fe3+-ZFA approached 100%, followed by Ca2+ (60-85%), Na+ (<25%), and Mg2+ (<5%). The difference in phosphate removal efficiency was explained by the adsorption mechanisms. It was concluded that ZFA could be used in simultaneous removal of NH4+ and phosphate at low concentrations with presaturation by an appropriate cation such as Al3+ through salt treatment.     

Ammonia release on heating of mechanically treated vermiculite saturated subsequently with ammonium

The differences in thermal behaviour of vermiculite before and after mechanical treatment (sonication and grinding), saturated subsequently with ammonium, were studied by TG, DTA, EGA and IR techniques. Sonication produces only a small modification in the NH₄ ⁺vermiculite decomposition attributed to a small particle size. Grinding causes an important but different change in the thermal behaviour of NH4-vermiculite. The temperature of ammonium loss is lowered stepwise showing that grinding modifies the bonding energy between and the surface of vermiculite. This revised version was published online in July 2006 with corrections to the Cover Date.     

碱金属和碱土金属离子在反相高效液相色谱柱上的保留机理

发现以酒石酸和吡啶二甲酸等羧酸水溶液作淋洗剂时，钠，铵，钾，镁和钙等碱金属及碱土金属离子在ＯＤＳ反相高效液相色谱柱上有明显的保留，而且相互之间能达到一定程度的分离。单独用分配或疏水作用等反相高效液相色谱的保留机理难以解释其保留行为。为此，作者提出了动态包固定相机理，即认为羧酸根阴离子因其疏水性在ＯＤＳ固定相有保留，在固定相表面形成具有羧酸基阳离子交换树脂功能的动态包覆固定相。     

毛细管区带电泳分析水中阳离子

选用一种新的缓冲液体系，采用毛细管区带电泳法，同时分离水中铵奶离子及碱金属、碱土金属和过渡金属等１２种分属不同类型的阳离子，并对电泳分离用金属阳离子弱络合剂、电解质ＰＨ值作了研究。方法用于环境水样分析，获得了满意效果。     

Use of mobile phase 18-crown-6 to improve peak resolution between mono- and divalent metal and amine cations in ion chromatography

It is difficult to quantify NH4+ by ion chromatography in the presence of high concentrations of Na+ due to peak overlap. The Dionex IonPac CS15 column, which contains phosphonate, carboxylate, and 18-crown-6 functional groups, was originally developed to overcome this problem. We have found that the addition of 18-crown-6 to the eluent promotes improved peak resolution between Na+ and NH4+ even at concentrations as high as 60,000 to 1 using this column. Its use also improves the separation of alkali and alkaline earth metal and amine cations. Mobile phase 18-crown-6 increased the retention times of CH3NH3+, NH4+, and K+, and decreased the retention time of Sr2+. The retention times of Li+, Na+, Mg2+, Ca2+, (CH3)2NH2+, and (CH3)3NH+ were not affected. This method makes possible the direct analysis of ammonia from nitrogenase, the enzyme responsible for biological nitrogen fixation. The resolution of the NH4+ peak from the Na+ and Mg2+ peaks improved from zero resolution to values of 6.19 and 5.65, respectively. This technique considerably reduces the analysis time of NH4+ in the presence of high concentrations of Mg2+ and Na+ over traditional indophenol measurements.     

Use of zwitterionic micelles in the eluent II: a new approach to ion chromatographic analysis of inorganic cations in biological fluids with direct sample injection

A new ion chromatographic (IC) technique has been developed for the determination of inorganic cations in biological fluids with direct sample injection. This involved the use of a mixed zwitterionic-micelle/electrolyte solution as an eluent. The proteins in the sample became bound to the zwitterionic micelles in the eluent and were thus eliminated from the column. The cations were separated by cation exchange. This method is ideal for the online, simultaneous determination of common inorganic cations (Na+, NH4+, K+, Mg2+, and Ca2+) in urine and serum samples. Such an application was demonstrated experimentally. Non-suppressed conductivity was used for analyte detection. The detection limits obtained using this IC system were 2.94, 5.22, 34.9, 32.6, and 56.7 microg/L for Na+, NH4+, K+, Mg2+, and Ca2+, respectively.     

Sodium, ammonium, calcium, and magnesium forms of zeolite Y for the adsorption of glucose and fructose from aqueous solutions

The kinetics of adsorption by sodium, ammonium, calcium and magnesium forms of zeolite Y from aqueous solutions containing 25% w/v of either one or an equimolar mixture of glucose (G) and fructose (F) have been studied batch-wise at 50 degrees C. The adsorption of aqueous pure G was fast, while that of aqueous pure F depended on the cationic form, approaching that of G on the Mg-Y, and slowing down in the sequence of Mg2+ > NH4+ > Ca2+ > Na+ of the cations. The adsorption behavior from solutions containing both G and F indicated significant hindering effects of F on G on Na-Y. Na-Y and Mg-Y did not exhibit rate-based selectivity, while Ca-Y an NH4-Y adsorbed G faster than F. Addition of CaCl2 to the mixture of Ca-Y and aqueous solution of G and F improved the separation, by hindering the adsorption of F. Addition of NH4Cl to the mixture of the sugar solution and NH4-Y, on the other hand, had a negative effect on the separation. NH4-Y was found to be desorbing about 30% of the adsorbed sugars and this value was found to be around 50% for Ca-Y. Re-adsorption experiments resulted in similar or somewhat higher percentages of amounts adsorbed compared to adsorption on fresh samples. Both NH4-Y and Ca-Y were found to be re-adsorbing around 50% of the sugars they adsorbed on fresh samples.     

离子色谱法同时分析中药中的碱金属与碱土金属离子

用离子色谱法简单快速地分析了中药中的阳离子。分析结果表明,川芎和酸枣仁中5种常见阳离子Na~+,NH~+_4,K~+,Mg~2+和Ca~2+的含量比例不同。各离子的检出限（S/N=3）为0.001～0.013mg／L,线性范围达3个数量级。     

Ultrafine Na-4-mica: uptake of alkali and alkaline earth metal cations by ion exchange

The cation exchange properties of alkali and alkaline earth metal cations at room temperature were investigated on an ultrafine, highly charged Na-4-mica (with the ideal mica composition Na4Mg6Al4Si4O20F4.xH2O). Ultrafine mica crystallites of 200 nm in size led to faster Sr2+ uptake kinetics in comparison to larger mica crystallites. The alkali metal ion (K+, Cs+, and Li+) exchange uptake was rapid, and complete exchange occurred within 30 min. For the alkaline earth metal ions Ba2+, Ca2+, and Mg2+, however, the exchange uptake required lengthy periods from 3 days to 4 weeks to be completed, similar to its Sr uptake, as previously reported. Kinetic models of the modified Freundlich and parabolic diffusion were examined for the experimental data on the Ba2+, Ca2+, and Mg2+ uptakes. The modified Freundlich model described well the Ba2+ ion uptake kinetics as well as that for the Sr2+ ion, while for the Ca2+ and Mg2+ ions the parabolic diffusion model showed better fitting. The alkali and alkaline earth ion exchange isotherms were also determined in comparison to the Sr2+ exchange isotherm. The thermodynamic equilibria for these cations were compared by using Kielland plots evaluated from the isotherms.     

不同形态的氧氟沙星在凹凸棒土上的吸附特征

通过控制反应体系的pH值,探究了阳离子、兼性和阴离子形态的氧氟沙星(OFL,3种形态分别记为OFL~+,OFL~±和OFL~-)在凹凸棒土(ATP)上的吸附特征.实验结果表明,OFL~+主要通过与ATP表面的Ca~(2+),Mg~(2+)进行阳离子交换吸附于ATP上,当其吸附量较高时,会存在少量的氢键;OFL~±和OFL~-可与ATP表面的铁氧化物、铝氧化物进行表面络合,也可与溶液中从ATP中溶解出的Ca~(2+)和Mg~(2+)形成络合物,再通过静电作用吸附于ATP上.在中性至微碱性(pH=7.10~7.70)条件下,由于Ca的电负性小于Mg,[Ca~(2+)-OFL]+不能稳定地存在于溶液中,使得OFL±与Ca~(2+)进行阳离子交换而与Mg~(2+)形成络合物,再通过静电作用吸附于ATP上.当OFL主要以OFL~-形态存在于溶液中时(p H=9.00~10.00),Ca~(2+)和Mg~(2+)均可与OFL~-形成络合物,再通过静电作用吸附于ATP上.     

微波消解样品-离子色谱法测定卷烟纸中钠、钾、镁、钙的含量

提出了离子色谱法同时测定卷烟纸中钠、钾、镁和钙含量的方法。卷烟纸试样经硝酸-过氧化氢-氢氟酸微波消解,以IonPac CS16阳离子交换柱为固定相,用0.027 mol.L-1甲烷磺酸溶液作流动相。钠、钾、镁和钙4种元素在30 min内可完全分离;各离子的检出限(3S/N)分别为13,15,8.1,97 mg.L-1。方法的加标回收率在100.9%～108.8%之间,测定值的相对标准偏差(n=5)在0.87%～3.4%之间。     

1,3-dialkylimidazolium-based room-temperature ionic liquids as background electrolyte and coating material in aqueous capillary electrophoresis

The 1-ethyl-3-methylimidazolium (EMIM) cation was found to have constant mobility of 4.5 x 10(-4) cm2 V(-1) s(-1) over the pH range of 3 to 11. The electroosmotic flow of bare silica capillary was reversed by the covalently bonded room-temperature ionic liquid (RTIL) coating. With run buffer of 5 mM EMIM (pH 8.5), NH4+ in human urine was separated from the K+ matrix and was detected to be 0.37 +/- 0.012%. K+, Na+, Li+, Ca2+, Mg2+ and Ba2+ were baseline separated in RTIL-coated capillary with run buffer of 10 mM EMIMOH-acetic acid at pH 5, and the concentration of the above ions in a red wine were detected to be 907, 27.9, 0, 71.0, 83.4 and 31.1 microg/ml, respectively. The RTIL-coated capillary showed stable electroosmotic flow for at least 80 h in the run buffer.     

离子色谱法测定饲料中氯化胆碱和三甲胺的含量

建立了离子色谱法测定饲料中氯化胆碱含量及鉴别饲料中氯化胆碱及掺假物三甲胺的方法。选用IonPac CS12阳离子交换色谱柱(250 mm×4 mm i.d.)和8.5 mmol/L H2SO4淋洗液,抑制型电导检测,在16 min内分离测定了包括胆碱和三甲胺在内的8种阳离子。胆碱和三甲胺的最小检出限分别为0.1 mg/L和0.05 mg/L。方法回收率为99.25%~102.5%。该方法具有灵敏度高、选择性强、操作简单等优点。     

低压离子色谱法分析茶水中的无机离子

1　引言离子色谱法在环境监测、食品、医药等领域都有重要用途[1 ] 。本实验室提出了低压离子色谱法[2 ,3] ,它可以在 1 .96～ 2 .94× 1 0 5Ｐａ(约 30～40ｐｓｉ)的低压下分析碱金属、ＮＨ+4、碱土金属、过渡金属阳离子、无机阴离子和有机酸根。仪器使用简单方便 ,实现了低压高效。茶叶成分及含量的研究正日益受到人们重视 ,有关资料表明[4] :细胞体液中 ,高浓度的Ｋ+才能使核糖体获得最大活性 ;Ｍｇ2 +是多种酶的激活剂 ,在机体中对蛋白质的合成、葡萄糖的氧化和细胞膜能量转换都是不可缺少的 ;磷素有“生命化学调控中心”之称 ,体内的磷…     

不同海藻吸附重金属镉离子的研究

本文采用6种分别属于褐藻门、绿藻门、红藻门的海边常见大型海藻对重金属镉离子进行吸附比较实验，镉离子浓度较低时，其吸附容量排列顺序为：海黍子＞海带＞孔石莼＞节荚藻＞刺松藻＞内枝藻，海黍子的吸附量高达181mg/g，超出文献报道值，对3种吸附容量较高的海藻进行了较详细的研究，研究溶液的pH值、初始Cd^2 离子浓度等因素对Ca^2 的吸附特性的影响，对吸附机理进行了初步的探讨，发现镉离子与海藻中的钙离子发生离子交换作用，交换率占总吸附量的33－34％，得出了适宜的吸附等温线方程。     

单柱离子排斥-阳离子交换色谱法测定酸雨组分

采用单柱离子色谱系统和电导检测的方法,首次以ＤＬ－苹果酸－甲醇水溶液为淋洗液,简便、有效地同时分离、检测了溶液ＳＯ＾－２４、Ｃｌ＾－、ＮＯ＾－３、Ｆ＾－、Ｎａ＾＋、ＮＨ＾＋４、Ｋ＾＋、Ｍｇ＾２＋、Ｃａ＾２＋９种离子。研究了ＤＬ－苹果酸浓度、甲醇浓度、流速和温度对各离子保留时间的影响。方法用于上海部分地区降水中的阴、阳离子分析,并与其它方法对比,结果良好。     

Capillary zone electrophoresis method for the simultaneous determination of cations in honey

A capillary electrophoresis system for the simultaneous determination of cations in honey samples has been developed. The complete separation and quantification of K+, Ca2+, Na+, Mg2+, Mn2+, Ni2+ and Li+, which represent more than 99% of the total content of cations in honey, can be achieved in 4 min with only a dilution and filtration of the honey sample. Electrolyte solution was composed by 10 mM imidazole as the carrier buffer and background absorbance provider and acetic acid as the complexing agent (pH 3.60). The running voltage was + 25 kV at 25 degree C. Indirect UV detection was achieved at 185 nm. Under the optimum conditions the detection limits ranged from 0.02 to 48.2 mg/kg and the quantification limits have ranged from 0.41 to 48.7 mg/kg. Precision data in honey samples analysed have shown repeatability and reproducibility RSD (%) lower than 2.84 and 6.62%, respectively. Recoveries of cations in honey samples analysed have ranged from 88.5 to 101.8%. These cations were identified by their relative migration times with regard to Ba2+ migration time used as reference standard and they were quantified by using an external standard calibration. Twenty-five honey samples were analysed to test the proposed method. Mean contents of 1.22 x 10(3), 93, 85, 54, 11, 1.9 and 2.3 mg/kg were found, respectively, for K+, Ca2+, Na+, Mg2+, Mn2+, Ni2+ and Li+ cations in analysed honeys. These results were similar than the obtained by other authors.