分离、富集液相中金离子的反应型材料

介绍了近年来国内外以化学吸附纤维(离子交换和螯合纤维)、活性炭纤维和树脂等有机功能材料为基础研究开发分离、富集液相中金离子(Au3 和Au )的研究进展,其中包括含N、O、S等各种官能团有机功能纤维和树脂、活性炭纤维对液相中金离子吸附的实验理论研究、预富集分析测试和实际湿法冶金中的应用,对于不同吸附材料对金离子的吸附行为、吸附机理、影响因素等进行了初步探讨。指出了反应型材料的优势和目前所存在的问题,对其应用前景作了适当展望。     

物理吸附系统的改造及其测试

根据测试需求和物理吸附系统的性能,对现有物理吸附系统进行功能升级改造.研制了一套气体吸附法的前处理设备,解决目前脱气设备不够用、超高表面积和超细孔径的材料脱气不彻底、因现有前处理设备温度波动大引起的金属-有机框架材料(MOF)和有机共价框架材料(COF)等新型材料内部结构坍塌等问题.搭建新的分析站,将目前效率低、测试性价比低的单站测试升级到高效率的双站测试.改善了液氮的添加工具,避免了测试人员的冻伤,避免了转移液氮工具的温度对测试数据的影响.在大量无机吸附质试验基础上,将物理吸附仪拓展到甲烷、丙烷、甲醇等有机气体吸附质试验,实现了双性吸附质的物理吸附测试,增强了仪器的功能范围.改进吸附环境装置,解决吸附过程中样品管出现冷凝现象,避免吸附量偏大,从而完善了物理吸附系统及其测试方法.     

Chemical oscillation with periodic adsorption and desorption of surfactant ions at a water/nitrobenzene interface.

Chemical oscillations with periodic adsorption and desorption of surfactant ions, alkyl sulfate ions, at a water/nitrobenzene interface have been investigated. The interfacial tension was measured with a quasi elastic laser scattering (QELS) method and the interfacial electrical potential was obtained. We found that this oscillation consists of a series of abrupt adsorptions of ions, followed by a gradual desorption. In addition, we observed that each abrupt adsorption was always accompanied by a small waving motion of the liquid interface. From the analysis of the video images of the liquid interface or bulk phase, we could conclude that each abrupt adsorption is caused by nonlinear amplification of mass transfer of ions from the bulk phase to the liquid interface by a Marangoni convection, which was generated due to local adsorption of the surfactant ions at the liquid interface that resulted in the heterogeneity of the interfacial tension. In the present paper, we describe the mechanism of the chemical oscillation in terms of the hydrodynamic effect on the ion adsorption processes, and we also show the interfacial chemical reaction with ion exchange during the ion desorption process.     

Ion adsorption and its influence on direct current electric field induced deformations of flexoelectric nematic layers

The influence of ion adsorption on the behavior of the nematic liquid crystal layers is studied numerically. The homeotropic flexoelectric layer subjected to the dc electric field is considered. Selective adsorption of positive ions is assumed. The analysis is based on the free energy formalism for ion adsorption. The distributions of director orientation angle, electric potential, and ion concentrations are calculated by numerical resolving of suitable torques equations and Poisson equation. The threshold voltages for the deformations are also determined. It was shown that adsorption affects the distributions of both cations and anions. Sufficiently large number of adsorbed ions leads to spontaneous deformation arising without any threshold if the total number of ions creates sufficiently strong electric field with significant field gradients in the neighborhood of electrodes. The spontaneous deformations are favored by strong flexoelectricity, large thickness, large ion concentrations, weak anchoring, and large adsorption energy.     

Adsorption of fluoride ions onto carbonaceous materials

The characteristics of fluoride ion adsorption onto carbonaceous materials were derived as adsorption isotherms at different temperatures and in different pH solutions. The fluoride ion was adsorbed into pores in carbonaceous materials produced from wood; the larger the specific surface area, the more fluoride ions adsorbed. Bone char was the most effective adsorbent. The composition of bone char includes calcium phosphate, calcium carbonate, and so on. This suggests that the phosphate ion in bone char was exchanged with a fluoride ion. Moreover, the mechanism of fluoride ion adsorption onto bone char is clearly chemical in nature because the amount of fluoride ion adsorbed onto bone char increased with increasing temperature and decreasing pH. The amount of fluoride ion adsorbed onto bone char was also shown to depend on the concentration of sodium chloride in solution because of the "salting-out" effect. The adsorption of fluoride ion onto bone char is endothermic. Bone char can be utilized to remove fluoride ions from drinking water.     

Study of the 137Cs adsorption performance of ion-eroded cement

For this study, ion-eroded cement was prepared from the cement required for construction of middle- and low-level radioactive waste repositories in caves. The properties for adsorption of ¹³⁷Cs on cement before and after ion erosion were investigated. XRF, XRD, SEM–EDS and BET were used to analyse various cement materials. The effects of reaction time, solid–liquid ratio, initial radioactivity and different ions on adsorption were studied by static batch experiments. When the initial radioactivity was 1114.5 Bq L^?1 and the solid–liquid ratio was 5 g L^?1, the adsorption equilibrium time was 12 h. Adsorption of ¹³⁷Cs on ion-eroded cement was more effective than that on untreated cement. The adsorption process was consistent with the pseudosecond-order kinetic model and the Freundlich isotherm model, and the process involved multilayer chemisorption. This study provides basic research data for construction of a disposal repository.

     

Amino acid adsorption on mesoporous materials: influence of types of amino acids, modification of mesoporous materials, and solution conditions

In order to disclose the dominant interfacial interaction between amino acids and ordered mesoporous materials, the adsorption behaviors of five amino acids on four mesoporous materials were investigated in aqueous solutions with adjustable amino acid concentration, ion strength, and pH. The selected amino acids were acidic amino acid glutamic acid (Glu), basic amino acid arginine (Arg), and neutral amino acids phenylalanine (Phe), leucine (Leu), and alanine (Ala), and the selected mesoporous materials were SBA-15, Al-SBA-15, CH3(10%)-SBA-15, and CH3(20%)-SBA-15. The adsorption capacities of Glu and Arg were strongly dependent on pH and surface charge of the mesoporous adsorbent. The adsorption of Phe showed pH insensitivity but depended on the surface organic functionalization of mesoporous adsorbent. On the basis of the theoretical analysis about the interaction between amino acid and adsorbent, such a remarkable difference was attributed to the different nature of the interaction between amino acid and adsorbent. Arg could be readily adsorbed on the surface of SBA-15, especially Al-SBA-15, under appropriate pH in which the electrostatic interaction was predominant. The driving force of Phe adsorption on mesoporous adsorbent mainly came from the hydrophobic interaction. Therefore, the adsorption capability of Arg decreased with increasing ion strength of solution, while the adsorption capability of Phe increased with the increasing degree of CH3 functionalization on SBA-15. For neutral amino acid Phe, Ala, and Leu, the adsorption capability increased with the increase of the length of their side chains, which was another evidence of hydrophobic effect. Thus, all the adsorption of amino acids on mesoporous silica materials can be decided by the combined influence of two fundamental interactions: electrostatic attraction and hydrophobic effect.     

Fibrinogen adsorption on blocked surface of albumin

We have investigated the adsorption of albumin and fibrinogen onto PET (polyethylene terephthalate) and glass surfaces and how pre-adsorption of albumin onto these surfaces can affect the adsorption of later added fibrinogen. For materials and devices being exposed to blood, adsorption of fibrinogen is often a non-wanted event, since fibrinogen is part of the clotting cascade and unspecific adsorption of fibrinogen can have an influence on the activation of platelets. Albumin is often used as blocking agent for avoiding unspecific protein adsorption onto surfaces in devices designed to handle biological samples, including protein solutions. It is based on the assumption that proteins adsorbs as a monolayer on surfaces and that proteins do not adsorb on top of each other. By labelling albumin and fibrinogen with two different radioactive iodine isotopes that emit gamma radiation with different energies, the adsorption of both albumin and fibrinogen has been monitored simultaneously on the same sample. Information about topography and coverage of adsorbed protein layers has been obtained using AFM (Atomic Force Microscopy) analysis in liquid. Our studies show that albumin adsorbs in a multilayer fashion on PET and that fibrinogen adsorbs on top of albumin when albumin is pre-adsorbed on the surfaces.     

Adsorption Behavior of Potassium Ion on Planting Materials

Characterization of planting materials used as adsorbent has been studied in order to compare potassium ion adsorption on two types of planting materials, which are a fired planting material （FPM） made from a mixture of 4 kinds of wastes （bottom ash, flue gas desulfurization （FGD） gypsum, paddy soil and sawdust） formed and fired at 850 ℃and the commercial planting material called ＂hydroball＂ （HDB） bought from Jatujak market, Bangkok. The physical characteristics of both types of planting materials indicate that the FPM has a larger specific surface area than the HDB. The factors affecting potassium adsorption on both the planting materials such as an equilibration time and some solid/solution ratios were investigated. The suitable equilibration time for the adsorption to reach an equilibrium on the FPM and HDB is one and two hours, respectively. The highest amounts of potassium ion adsorbed on both the planting materials were obtained when the solid/solution ratio was 1 ： 15. The adsorption behavior on both the planting materials tends to correspond with the Freundlich isotherm.     

制备方法对AgCeY吸附剂脱硫性能的影响

以硅铝比为5.3的NaY分子筛为母体,分别采用微波辅助离子交换法(AgCeY-1)、水热离子交换法(AgCeY-2)和液相离子交换法(AgCeY-3)制备了AgCeY-n吸附剂,并利用XRD、BET、XPS和Py-FTIR对吸附剂进行了表征。以噻吩和苯并噻吩为模型硫化物,甲苯和环己烯为竞争吸附组分,考察了制备方法对制备得到的吸附剂脱硫性能的影响。结果表明,AgCeY-n吸附剂上Ag、Ce元素分别以Ag~+、Ce~(4+)形式存在。经微波辅助离子交换法制备得到的AgCeY-1吸附剂表面Ag~+、Ce~(4+)含量均最高,且具有最高的L酸和B酸量。AgCeY-n吸附剂对硫化物的吸附选择大小顺序为:BTTP,竞争吸附组分对AgCeY-n吸附脱硫性能的影响顺序为:环己烯甲苯。在所研究的制备方法中,微波辅助离子交换法所需时间最短(20 min),合成的AgCeY-1对所研究的模拟油的吸附效果均最好,且具有较好的重复使用性能。各吸附剂对TP和BT的脱除能力大小顺序为:AgCeY-1AgCeY-2AgCeY-3。     

微塑料富集金属铅元素的能力与特征分析

以微塑料为载体,考察了其对溶液中铅离子的富集能力。首先利用2%HNO_3为解吸溶液,并用超声波仪进行辅助解吸,然后用电感耦合等离子体质谱仪(ICP-MS)测定其吸附的铅含量,从而研究微塑料吸附铅离子的能力。对微塑料的材质、吸附时间、粒径、离子浓度、选择性以及共存离子等进行了考察,分析了微塑料吸附铅离子的特征。实验结果表明:不同材质的微塑料对铅离子的吸附能力不同,其中聚氯乙烯(PVC)、聚丙烯(PP)吸附量最高,分别达到1.32μg/g和0.63μg/g。微塑料粒径越大,其对铅离子的吸附量越低。随着吸附时间和铅离子浓度的增加,微塑料对铅离子的吸附效率出现先升后降的趋势。共存离子实验表明,当溶液中存在其他离子时,不同材质的微塑料对铅离子的吸附能力受到不同程度的影响,当铅离子和铜离子共存时,2种离子存在竞争性吸附现象。该文探索了微塑料对铅离子的吸附特性,可为深入研究海洋中微塑料富集重金属及其环境行为提供理论基础。     

Kinetic,isothermal and thermodynamic studies on Th(IV) adsorption by different modified activated carbons

In this study, the performance of modified adsorbents obtained from activated carbon for the adsorption of thorium(IV) ions from aqueous media was investigated. The analytical and spectroscopic methods such as FT-IR, BET, SEM and UV–Vis were used to examine the properties of the modified materials. According to the analysis results, the both adsorbents had large surface areas after modification. Then, temperature, pH, mixing time and solution concentration parameters were observed to determine optimum thorium adsorption conditions on modified materials. The obtained results from the experiments were applied different three kinetic models and adsorption isotherms and thermodynamic parameters were calculated and then all of the results were interpreted. The adsorption process for both adsorption systems was observed to be compatible with the pseudo-second-order kinetic model. The adsorption equilibrium data were best described by the Langmuir model for modified adsorbent with KMnO₄ and by the Freundlich model for modified adsorbent with NaOH. Furthermore, the calculated thermodynamic parameters (ΔG°, ΔH° and ΔS°) showed that the both adsorption processes were endothermic and spontaneous. The data show that modified adsorbents can be used as influential and low-cost adsorbents to remove thorium ion. Modified new adsorbents were highly selective for thorium ion in competitive adsorption studies.

     

聚季铵盐离子液体材料制备及其对蛋白质吸附性能评价

通过一步合成法制备了两种可聚合季铵盐离子液体功能单体,并通过沉淀聚合法合成了相应的聚离子液体聚合物。对产物进行了核磁共振、扫描电镜、热重分析等表征。结果表明:所制备的两种材料粒径均匀,约为600 nm的椭球形颗粒,颗粒之间有相互粘连。通过对牛血清白蛋白(BSA)、卵清蛋白(OVA)、牛血红蛋白(BHb)、溶菌酶(Lys)、胰蛋白酶(Try)5种蛋白质的吸附性能实验,考察了聚季铵盐离子液体材料对蛋白质的吸附性能。考察结果表明:两种聚离子液体材料均对蛋白质具有一定的吸附性能。其中以4-乙烯基苄氯季铵盐离子液体为功能单体制备的聚离子液体材料对胰蛋白酶的吸附性能最好,是一种具有良好应用前景的材料。     

Biosorption of As3+ Ions Using Ternary Microspheres of Chitosan,Yeast, and Gelatin: A Dynamic and Equilibrium Investigation

Ternary biopolymeric microspheres of chitosan, yeast and gelatin were prepared and characterized by FTIR spectral analysis, particle size measurements, and scanning electron micrograph techniques. The prepared microspheres were investigated for static and dynamic studies of adsorption of As⁺³ ions onto the microspheres surfaces at fixed pH and ionic strength of the aqueous solution.The adsorption data were applied to Langmuir and Freundlich isotherm equations and various static parameters were calculated. The dynamic nature of adsorption was quantified in terms of several kinetic constants such as rate constants for adsorption, Lagergreen rate constant, inter particle diffusion rate constant and pore diffusion coefficient. The influence of various experimental parameters such as solid to liquid ratio, pH, temperature, and chemical composition of biopolymeric microspheres were investigated on the adsorption of arsenic ion and various thermodynamic parameter were also calculated.     

Modification of active carbon and zeolite as ammonia separation materials for a new de-NO<Subscript>x</Subscript> process with ammonia on-site synthesis

Ammonia adsorption and desorption behavior of surface treated active carbon (AC) and ion-exchanged Y zeolite, as ammonia separation and storage materials for a new de-NO_x process with ammonia on-site synthesis, were studied. Surface oxidized AC adsorbed more ammonia than non-treated AC due to ammonium ion formation. These materials were found to increase weak adsorption of ammonia and to be useful for pressure swing adsorption. Transition metal ion exchanged Y-zeolite adsorbed more ammonia (both weak and strong form) than Na Y-zeolite due to ammine complex formation. These materials adsorb and desorb more ammonia than treated AC when used for temperature swing adsorption.     

改性纤维素的制备及分光光度法对Cu~(2+)吸附研究

针对日益严重的铜离子污染问题,以化学浆纤维素为原料,通过氨基酸接枝修饰2,2,6,6-四甲基哌啶氧自由基(TEMPO)氧化体系氧化的纤维素,制备出一种新型吸附剂,并采用灵敏简便的分光光度法研究改性对铜离子的吸附效果。结果表明,氨基酸修饰纤维素(AMC)与TEMPO氧化纤维素(TOC)相比,对铜离子的吸附效果有不同程度的提升,其中组氨酸改性的吸附效果最好,低浓度时吸附率可以高达97%。随着浓度增大,吸附率下降,但是吸附量增大,当吸附200 mg/L的Cu2+溶液时,吸附量可达47 mg/g。此外,研究了不同条件下AMC对Cu2+的吸附情况,包括AMC投加量、初始浓度、pH值等。结果表明,吸附过程的吸附模型符合Langmuir等温模型,吸附动力学可以用准二级吸附动力学方程拟合。     

Impedance analysis of an electrode-separated piezoelectric sensor as a surface monitoring technique for surfactant adsorption on quartz surface

This paper describes the measurement of the kinetics of adsorption of sodium dodecyl sulfate (SDS), an anionic surfactant, onto a quartz surface with a pre-adsorbed layer of Ca2+ as an ion bridge, using an electrode-separated piezoelectric sensor (ESPS). An impedance analysis method was employed to characterize the responses of the ESPS. The impedance and frequency parameters of the ESPS were examined as functions of the conductivity, permittivity, viscosity and density of the liquid. The adsorption process of SDS onto the quartz surface resulted in an increase in both the mass and energy dissipation of the oscillating quartz crystal. The adsorption densities could be estimated by the ESPS method after taking into consideration the effects of surface viscosity and roughness. The adsorption and desorption rate constants of SDS onto the quartz surface were calculated as ka = (88.1 +/- 0.26) mol(-1) L s(-1) and kd = (4.92 +/- 0.53) x 10(-3) s(-1), respectively, based on the Langmuir model. ESPS was shown to be a powerful means of examining anionic surfactant adsorption to the solid/liquid interface.     

全无霜空气源热泵系统及吸附式除湿方法

总结了多种全无霜空气源热泵的系统原理和实现无霜化的吸附式除湿技术。介绍了液体吸附式和固体吸附式全无霜空气源热泵系统,并比较其优缺点,前者具有大量处理湿空气的优点,后者具有能效比高等优点。对吸附式除湿的吸附材料和吸附装置进行综述,介绍了能低温再生和吸附量较大的吸附材料。最后指出,吸附材料和除湿装置需要进一步研究从而提高除湿和再生效率,而系统需要进一步优化,以降低其初始成本和运行成本,从而提高市场应用潜力。     

Confinement effect on the adsorption from a binary liquid system near liquid/liquid phase separation

The preferential adsorption of one component of a binary system at the inner surfaces of mesoporous silica glasses was studied in a wide composition range at temperatures close to liquid/liquid phase separation. Confinement effects on the adsorption were investigated by using three controlled-pore glass (CPG-10) materials of different mean pore size (10 to 50 nm). For the experimental system (2-butoxyethanol+water), which exhibits an upper miscibility gap, strong preferential adsorption of water occurs, as the coexistence curve is approached at bulk compositions, at which water is the minority component. In this strong adsorption regime the area-related surface excess amount of adsorbed water decreases with decreasing pore width, while the shift in the volume-related mean composition of the pore liquid shows an opposite trend, i.e., greatest deviation from bulk composition occurring in the most narrow pores. A simple mean-field lattice model of a liquid mixture confined by parallel walls is adopted to rationalize these experimental findings. This model reproduces the main findings of the confinement effect on the adsorption near liquid/liquid phase separation.     

盐湖卤水提锂分离材料的研究进展

采用吸附或离子交换技术直接从中低锂含量盐湖卤水中提取锂是最经济、最理想的提锂技术路线,寻找、研究性能优异的锂的吸附分离材料,是实现这一技术路径的关键。重点阐述了离子交换与吸附法提锂的各种分离材料,并指出了盐湖卤水提锂今后的研究方向。