离子色谱中淋洗液浓度和pH值对分析结果的影响

本文主要介绍，离子色谱中淋洗液的浓度ｐＨ值对分析结果的直接影响，通过实践总结出了正确选择淋洗液，既可改善分离效果，又可提高分析效率。     

离子色谱法测定有害工业固体废物浸出液中的氟化物

用离子色谱法（简称ＩＣ）测定有害工业固体废物浸出液中的氟化物，其测定方法较化学法（离子选择电极法）手续简便、快速、准确．     

离子色谱法在高纯水分析中的应用

离子色谱法作为一种快速、准确而有效的分析方法在高纯水分析方面得到了广泛的应用.所涉及的领域除半导体、电力工业外,还包括环境、地质、生命科学等诸多方面.美国戴安公司(Dionex Corp)作为全球最大的离子色谱专业生产厂家,近年来发展了多种测定高纯水超痕量离子的方法.高纯水中超痕量的离子经预富集后可测至ng/1 级,其最新型的DX-500型离子色谱仪可在直接进样的情况下对部分离子进行μg/1 级的测定。     

离子色谱法测定烟气中的尘态氟

建立了一种简便、快速测定废气中尘态氟的离子色谱分析方法。用滤筒采集样品,以碳酸钠-碳酸氢钠混合液为淋洗液,用离子色谱进行样品分离,面积外标法定量。分析结果表明,该方法操作简便、离子色谱条件的线性理想,测定结果的回收率、精密度和准确度较高。适用于污染源废气尘态氟的测定。     

小球藻对Pb2+吸附及其亚细胞分布研究

通过溶液培养小球藻Pb2+暴露实验分析小球藻对Pb的富集以及亚细胞分布情况.结果表明:小球藻对Pb的富集总量随暴露浓度、暴露时间的增加而增加.运用差速离心法研究了小球藻中Pb在亚细胞中的分布,热力学实验与动力学实验的细胞分布结果均表明含细胞壁等残渣部分(组分I)中Pb的浓度远高于含细胞核、叶绿体、线粒体等细胞器膜系统(组分II)和可溶蛋白等细胞溶质部分(组分III)中Pb的浓度.采用动力学模型与等温线方程对实验数据进行拟合,结果表明小球藻对于Pb2+的生物吸附过程适宜用Elovich方程和二级吸附速率方程采描述,生物吸附平衡可用Langmiur等温式和Freundlich等温式来描述,小球藻对于Pb2+的生物吸附为非均相的扩散过程.     

Enhanced adsorption of Methylene Blue from aqueous solution by chitosan-g-poly （acrylic acid）/vermiculite hydrogel composites

A series of chitosan-g-poly (acrylic acid)/vermiculite hydrogel composites were synthesized and used as adsorbents for the investigation of the e ect of process parameters such as vermiculite content, pH of dye solution, contact time, initial concentration of dye solution, temperature, ionic strength and concentration of surfactant sodium dodecyl sulfate on the removal of Methylene Blue (MB) from aqueous solution. The results showed that the adsorption capacity for dye increased with increasing pH, contact time and initial dye concentration, but decreased with increasing temperature, ionic strength and sodium dodecyl sulfate concentration in the present of the surfactant. The adsorption kinetics of MB onto the hydrogel composite followed pseudo second-order kinetics and the adsorption equilibrium data obeyed Langmuir isotherm. By introducing 10 wt.% vermiculite into chitosan-g-poly (acrylic acid) polymeric network, the obtaining hydrogel composite showed the highest adsorption capacity for MB, and then could be regarded as a potential adsorbent for cationic dye removal in a wastewater treatment process.     

铜离子和孔雀绿在磷酸酯化改性豆壳上的吸附行为

报道了一种功能基为磷酸羟基的酯化豆壳阳离子吸附剂的固相制备技术,研究了铜离子和孔雀绿在改性豆壳上的吸附行为.采用静态批次试验研究了不同实验参数(pH值、吸附剂用量、吸附质浓度和吸附时间)对铜和染料吸附的影响.铜离子和孔雀绿分别在pH≥3.0和6.0时达到最大吸附值.对于浓度为100 mg·L-1的铜溶液,5.0 g·L-1及以上的改性豆壳能去除91%以上的铜;改性豆壳用量≥2.0 g·L-1时,能去除浓度为250 mg·L-1的溶液中95%以上的孔雀绿.改性豆壳对铜离子和孔雀绿的吸附符合Langmuir吸附等温线模型,最大吸附能力分别为31.55 mg·g-1和178.57 mg·g-1.对铜离子和孔雀绿的吸附分别在75 min和7 h达到吸附平衡,准一级反应动力学方程和准二级反应动力学方程能分别描述铜离子和孔雀绿在改性豆壳上的吸附过程.     

Characteristics of isothermal adsorption and desorption of aluminum ion to/from humic acids

The adsorption and desorption characteristics of Al3+ to/from humic acids at di erent pH, ionic strength, and temperature were studied by the C-25 glucosan-gel chromatography method. The results showed that the maximum adsorption amount (Qmax) and adsorption constant (k) increased, whereas, the absolute value of standard thermodynamic molar free energy change ( G0 m) decreased with the increase of pH at constant ionic strength and temperature. With ionic strength increasing from 0 to 0.15 mol/L, Qmax and k increased and the absolute value of G0 m decreased at constant pH and temperature. High temperature was unfavorable for the adsorption reaction, as indicated by the dramatic decrease of Qmax and the absolute value of G0 m with an increase in temperature. The standard thermodynamic molar free energy change ( G0 m) and the standard thermodynamic enthalpy change ( H0m ) of the adsorption reaction were both negative, suggesting that adsorption reaction was spontaneous and exothermic. The desorption rate of HA-Al3+ complex accelerated with the decrease of pH, and a significant linear relationship could be obtained between pH and the desorption rates of Al3+ from humic acids. These results demonstrated that the Al3+ adsorption reaction was a “biphase” reaction, and adsorption occurred at both the interior and exterior adsorption sites of humic acids.