复合型螯合吸附材料PEI/SiO2对铜离子吸附性能的研究

通过γ-氯丙基三甲氧基硅烷的媒介, 将聚乙烯亚胺(PEI)偶联接枝到硅胶微粒表面, 制备了复合型螯合吸附材料PEI/SiO2;研究了PEI/SiO2对Cu2 的吸附性能. 复合型螯合吸附材料PEI/SiO2对Cu2 具有强的螯合吸附能力;等温吸附数据符合Langmuir方程, 且吸附量随温度升高而增大;pH对吸附量有很大的影响, pH 7时, 吸附量最高.     

磁性交联壳聚糖微球对Cu2+的吸附性能研究

以Fe_3O_4为磁核,环氧氯丙烷为交联剂,制备磁性交联壳聚糖微球(MCB)。采用FTIR、XRD及SEM对MCB进行表征分析,结果表明壳聚糖发生了交联反应,且Fe_3O_4被壳聚糖包埋。通过正交试验L_9(3~4),得到MCB的最优制备工艺条件为:环氧氯丙烷用量为3.0 mL,反应温度为45℃,反应时间为3.0 h,MCB对Cu~(2+)的吸附率可达63.70%。同时在单组分体系中研究了MCB对Cu~(2+)的吸附行为,结果表明:MCB对Cu~(2+)的最佳吸附pH值为5.0,MCB对Cu~(2+)的吸附遵循Langmuir等温吸附模型;动力学研究表明,MCB对Cu~(2+)的吸附过程符合拟二级吸附动力学方程。     

PNVA-g-PSt微球的功能化与离子吸附研究

由大分子单体法合成了表面聚N-乙烯基乙酰胺接枝聚苯乙烯(PNVA-g-PSt)微球,通过对该接枝链进行化学改性得到了新型功能化高分子微球.用透射电子显微镜、激光光散射和X射线光电子能谱对高分子微球的形态、表面组成和直径大小进行了表征,发现微球经水解后形态更加规整,在分散状态下直径有所增加且保持核-壳型结构.实验比较了几种高分子微球对Cu2 ,Pb2 离子的吸附效果.定量测定结果表明:高分子微球经功能化处理后,其吸附效果有了很大的改进,在较低浓度范围,Pb2 离子的脱除率可达100%.     

铜离子印迹聚合物的吸附性能研究EI北大核心CSCD

以二苯氨基脲为功能单体,合成了铜离子印迹聚合物(Cu^(2+)-IIPs),并用于Cu^(2+)的快速吸附检测。对Cu^(2+)-IIPs进行了表征,考察了其对Cu^(2+)的吸附特性。结果表明,Cu^(2+)-IIPs为球型状颗粒且粒径分布均匀,印迹位点位于表面及空穴中,对Cu^(2+)的吸附过程符合准二级动力学模型,吸附速率受表面吸附和内部扩散共同影响。较之Langmuir模型和Tempkin模型,Freundlich模型能更好地拟合吸附等温线,说明属于多层吸附;ΔG^(0),ΔH^(0)和ΔS^(0)的数据显示,吸附是一个自发进行的、吸热的、熵增大的过程;Cu^(2+)-IIPs对Cu^(2+)的吸附量远大于具有相似结构和性质的其它重金属离子,因而具有良好的吸附选择性。     

顺丁烯二酸-co-苯乙烯微球对Cd(Ⅱ)的吸附行为研究

以火焰原子吸收光谱法(FAAS)为检测手段,研究了本实验室合成的顺丁烯二酸-苯乙烯共聚物微球对Cd(Ⅱ)的静态吸附性能,考察了影响吸附率的相关因素以及不同浓度的各种解吸剂对Cd(Ⅱ)的解吸效果.溶液pH为6、吸附时间为2h时吸附基本达到平衡,吸附率可达到95%以上.以3 mol/,L的HCI溶液作为解吸剂对Cd(Ⅱ)进...     

聚丙烯腈微球预富集分离微柱与FAAS联用测定痕量Cd(Ⅱ)和Zn(Ⅱ)

将自制的聚合物微球填充到玻璃柱制备了2.5cm×4 mm i.d.预富集分离柱,并将其与火焰原子吸收光谱(FAAS)法联用,测定了其对Cd2和Zn2+的动态吸附,建立了测定溶液中痕量Cd2+和Zn2+的预富集分离-FAAS方法;优化了对Cd2+和Zn2+的吸附富集与洗脱条件,在室温下,溶液pH为5～6,上样和洗脱液流速...     

铜离子印迹聚合物的制备及性能研究

在乙醇溶液中,以Cu(Ⅱ)为模板分子,二甲基丙烯酸乙二醇酯为交联剂采用分散聚合法制备铜离子印迹聚合物(Cu~(2+)-IIP),并通过傅里叶变换红外光谱、紫外光谱对聚合物的结构及性能进行了表征。考察了吸附时间、溶液初始浓度、pH值等因素对聚合物吸附性能的影响。实验表明,室温条件下,在pH=6,90min吸附达到平衡,其最大吸附量为1.42mmol/g;与非印迹聚合物相比,印迹聚合物有较大的吸附量及较好的选择性。因此,印迹聚合物在固相萃取、水处理等方面具有很好的应用前景。     

淀粉微球吸附性能的研究

本文对淀粉微球ＴＳＭ的吸附性能进行了研究，测试了ＴＳＭ的最大的吸附量和不同温度下的等温吸附线，并计算出ＴＳＭ的吸附热，得出ＴＳＭ对亚甲基兰的吸附属于化学吸附。将单分子层固－气吸附引入固－液吸附体系，证实了Ｌａｎｇｍｕｉｒ单分子层吸附机理在该体系中的可适用性，计算出５℃时ＴＳ的等温吸附方程为ｑ＝ＴＳＭ的吸附速率方程式为＝０．９４５。     

凤眼莲对铜离子的生物吸附研究

为探讨滇池凤眼莲对水中重金属离子Cu2 的吸附特性,考察了pH、时间、吸附剂量、浓度等因素对吸附能力的影响,进行了实验室吸附试验,绘制出吸附等温线,并由Langmuir曲线求出相应参数.对凤眼莲进行了脱附-再生实验.分析了吸附机理.结果表明,在pH3.5～5.5范围内,凤眼莲对Cu"有吸附作用,饱和吸附量可达35.6mg/g,吸附等温式为Cf/q=0.027Cf 0.114.用0.5mol/LHCl和NaOH可使其脱附与再生.     

麦饭石对水溶液中铜（Ⅱ）离子吸附的研究

麦饭石作为净水剂,能够去除水中的镉、汞和铜等重金属离子。但对于其吸附平衡的研究还未见报道。本文以静态法考查了泰山麦饭石对水溶液中铜(Ⅱ)离子吸附的平衡特性。     

铅离子印迹固相萃取原子吸收光谱分析

以Pb2+为模板,丙烯酸为功能单体,乙二醇二甲基丙烯酸酯为交联剂,采用本体聚合技术,制备了对Pb2+具有特异性识别作用的离子印迹材料。通过红外光谱,吸附容量,干扰实验等讨论了该离子印迹材料的相关性质。结果表明,该离子印迹材料对Pb2+的结合能力明显强于非印迹材料,能够很好的排除其他金属离子的干扰。通过制备该离子印迹材料,能够富集水体中的痕量铅,结合原子吸收光谱法对其进行定量分析,为测定复杂环境样品中痕量铅离子提供一个高选择性,高预富集效率的固相萃取材料和分析方法。     

Effects of denaturation and association of collagen on adsorption behavior: two-dimensional nanostructure and its property

Effects of denaturation and association of collagen on adsorption behavior were studied in various pH and temperature T by a quartz crystal microbalance QCM. The surface nanostructure, the adhesion force F _ad, and the local frictional coefficient μ of collagen were studied by an atomic force microscope AFM and a lateral force microscope LFM. Adsorptions of collagen were Langmuir type in the regions of pH 3.0–5.8 and T = 25–50 °C. With increasing pH and T, adsorption mass Γ increased, and adsorbed fibrils increased in width. At interface, the association of collagen molecules in solution enhanced the formation of fibrils. The results of F _ad in the solution of pH 3.0 increased with increasing Γ and T but decreased in pH 5.8. The results of μ increased with increasing Γ and T, and those in pH 3.0, were much greater than those in pH 5.8. From comparing them with the results of bovine serum albumin and sodium hyaluronate monolayer, we concluded that nonelectrostatic interactions and the softness of collagen layer contribute primarily to F _ad and μ.     

接枝壳聚糖对铅、镉吸附行为研究及应用

在碱性条件下,用环氧氯丙烷交联制备水不溶性交联壳聚糖(CCTS),将丙烯腈单体接枝到CCTS分子骨架上制得接枝壳聚糖(CTCA)。研究了CTCA对水中Pb2 、Cd2 的吸附富集行为和洗脱行为,用原子吸收光谱法测定。结果表明,溶液的pH值为6.0时,Pb2 、Cd2 的吸附率达94%和95%,吸附容量分别达到56.6 mg/g、47.0 mg/g。用1 mol/L HCl洗脱,Pb2 、Cd2 的解吸率均可达97%。方法的检出限为:Pb2 ,0.065μg/L;Cd2 ,0.024μg/L。对10 mg/L的Pb2 、Cd2 溶液进行分离富集和测定,其相对标准偏差为3.4%和5.2%。方法已用于天然水中Pb2 、Cd2 的分离富集和测定,其回收率:Pb2 ,94%~101.9%;Cd2 ,95.6%~108%。     

Adsorption behavior of Pb(II) on montmorillonite

The present work investigated the adsorption and desorption behaviors of Pb(II) on montmorillonite. The adsorption experiments were carried out using batch process. The results show that the adsorption is dependent on the pH value of the medium, and the uptake of Pb(II) increases with the pH increasing in the pH range of 2.0–10.0. The adsorption kinetics is in better agreement with pseudo-second order kinetics, and the adsorption data is a good fit with Langmuir isotherm. The presence of EDTA may result in a decrease of the amount of Pb(II) adsorbed. The presence of electrolyte and EDTA may enhance the desorption of Pb(II) ions adsorbed. The adsorption mechanism of Pb(II) on montmorillonite may be explained in two aspects: the chemical binding between Pb(II) ions and surface hydroxyl groups; and the electrostatic binding between Pb(II) ions and the permanent negatively charged sites of montmorillonite.     

Concentration of heavy metal ions in water using thermoresponsive chelating polymer

Thermoresponsive polymers, poly(N-isopropylacrylamide) (PNIPAAm), having chelating functionalities were synthesized. PNIPAAm-imidazole (-Im) was precipitated and formed a gum-like aggregate in the neutral pH region at 50 °C, while PNIPAAm-carboxylic acid (---COOH) and PNIPAAm-iminodiacetic acid (-IDA) remained soluble even at pH 7. An addition of a paired ion, dodecyltrimethylammonium ion, was effective for inducing the precipitation of those polymers. PNIPAAm-Im was useful for collecting copper(II), nickel(II), cobalt(II), and lead(II), but was ineffective for cadmium(II) recovery. In contrast, PNIPAAm-COOH collected cadmium(II), while insufficiently recovered cobalt(II) and nickel(II). PNIPAAm-IDA was the best choice for collecting all metal ions in neutral pH's. After 20-folds concentration, the metal ions in river and seawater were successfully determined by graphite furnace atomic absorption spectrometry (GFAAS).     

纳米二氧化钛对痕量铅的吸附性能研究

提出了纳米TiO2分离富集, 火焰原子吸收光谱法测定水样中痕量铅的新方法.考察了铅在纳米TiO2上的吸附动力学、最佳酸度和吸附容量.实验结果表明：在最佳实验条件下,纳米TiO2能定量、快速地吸附水中的痕量Pb^2＋,其静态吸附容量为17.90 mg/g.吸附在纳米TiO2上的Pb^2＋可用0.1 mol/L HNO3＋0.1 mol/L CH3COOH完全洗脱.对Pb2＋的检出限为2.57 ng/mL, 相对标准偏差为2.5% （n=11, ρ=0.10 μg/mL）,加标回收率在94.5%～102.5%之间.可用于实际水样中铅的测定.     

有机-无机介孔材料对痕量汞的吸附性能的研究

研究了一种有机-无机介孔材料在分离富集和测定痕量汞中的应用,探讨了溶液pH、温度、洗脱条件及干扰离子对汞分离富集的影响,结果发现该材料对Hg的吸附具有较高的选择性和较大的吸附容量。在pH 3.2、温度为20±1℃条件下,汞可被该材料定量吸附。其静态饱和吸附容量为119.15 mg/g。吸附的汞可用浓HCl洗脱,用原子荧光法测定洗脱下来的汞。该方法测定汞的检出限达1.89×10-9g/L(3σ),相对标准偏差为2.7%(n=11,ρ=0.5 ng/mL),线性范围为0.005~5 ng/mL,加标回收率95.3%~104.5%。此法已应用于环境水样中痕量汞的测定。     

Ultrasound-assisted adsorption of Pb ions by carbonized/activated date stones from singles/mixed aqueous solutions

This work aims to assess the adsorption efficiency of date stones biowaste subjected to carbonization and activation processes for the removal of Pb ions from single and mixed solutions. Several techniques have been used for characterization of adsorbents such as scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), methylene blue index and point of zero charge (pHpzc). An excellent adsorption capacity of 97.43% is achieved at an initial concentration of 300 ?mg/L, solution volume 75 ?mL of Pb nitrate, adsorbent mass of 0.7 ?g, temperature of 30 ?°C, a stirring speed of 500 ?rpm/min, a contact time of 180 ?min and pH 6. Specifically, a comparison has been conducted between carbonized/activated date stones “CADS” and commercial activated carbon “CAC” besides investigating the influence of the presence of Co ions and the utilization of ultrasound radiation. A higher adsorption rate of 98.16% is reached under ultrasound radiation at Pb(II) initial concentration of 100 ?mg/L for a contact time of 3 ?h. Nevertheless, the temperature has shown a negative effect; the adsorption rate decreases from 98.31% at 18 ?°C to 92.70% at 60 ?°C. The modeling of the experimental adsorption data manifests a type-L isotherm characteristic of Langmuir and Freundlich models. The kinetic study has shown that the experimental data are well described by a pseudo-second-order rate model and controlled by the internal diffusion, a limiting-step that controls the transfer rate of Pb(II) to the adsorbent surface. The calculated thermodynamic parameters (ΔG⁰, ΔH⁰, ΔS⁰) indicate that the adsorption of Pb(II) is spontaneous and exothermic process.     

Use of silica gel chemically modified with zirconium phosphate for preconcentration and determination of lead and copper by flame atomic absorption spectrometry

An analytical method using silica gel chemically modified with zirconium (IV) phosphate for preconcentration of lead and copper, in a column system, and their sequential determination by flame atomic absorption spectrometry (FAAS), was developed. Sample solutions are passed through a glass column packed with 100 mg of the sorbent material, at pH 4.5, and lead and copper are eluted with 1.0 mol l⁻¹ HNO₃ at a flow rate of 2.0 ml min⁻¹. The extraction of copper is affected by Fe(II), Mn(II), Zn(II), Ni(II) and Co(II) while only Fe(II) interferes in the lead determination. These interferences may be overcome with an appropriate addition of a KI or NaF solution. An enrichment factor of 30 was obtained for both metals. While the limits of detection (3σ) were 6.1 and 1.1 μg l⁻¹, for Pb and Cu, respectively, the limits of determination were 16.7 and 3.3 μg l⁻¹. The precision expressed as relative standard deviation (R.S.D.) obtained for 3.3 μg l⁻¹ of Cu and 16.7 μg l⁻¹ of Pb were 4.3 and 4.7%, respectively, calculated from ten measurements. The proposed method was evaluated with reference material and was applied for the determination of lead and copper in industrial and river waters.     

Study of adsorption of tetraethylammonium ions on Bi single crystal planes from solutions in ethanol

The adsorption of tetraethylammonium (TEA⁺) ions on the (001) and planes of the bismuth single crystal from solutions in ethanol has been investigated by impedance measurement method. The experimental data were obtained in 0.02 M mixed-electrolyte solutions and the calculations performed with electrode potential as the independent electrical variable. The Gibbs energy of adsorption of TEA⁺ ions has been calculated using the simple virial adsorption isotherm, and it was found that the adsorption of TEA⁺ cations is weaker than the adsorption of halide anions. The electrosorption valency evaluated has a nearly constant value in the potential region studied. It was concluded that the formed effective surface dipole is significantly screened by the solvent molecules and the metal electron gas. The analysis of the impedance spectra was performed by fitting the experimental data to the various equivalent circuits. It was found that the behaviour of TEA⁺ ions at Bi(hkl)∣ethanol interface can be described with the equivalent circuit, corresponding to the classical Frumkin–Melik-Gaikazyan model. The results obtained indicate that only weak interaction between TEA⁺ ions and bismuth surface takes place, and there is no remarkable partial charge transfer from the adsorbed ions to the Bi surface atoms.