离子交换纤维吸附和解吸阿魏酸的性能研究

较系统地研究了自制的强碱性阴离子交换纤维吸附、解吸 阿魏酸的条件。实验结果表明,该离子交换纤维对阿魏酸 的静态饱和吸附量为180.4mg/g(干纤维)。离子交换纤维 吸附阿魏酸时以液膜扩散为主控步骤,其液膜吸附速率 常数k=1.55×10-3s-1。对不同入口浓度和不同流速下,阿魏 酸在固定床吸附柱上的动态吸附过程进行了研究。用少 量甲醇和稀盐酸即可将吸附在纤维上的阿魏酸完全解 吸。

低湿条件下离子交换纤维吸附性能的研究

以超高交联聚丙烯-苯乙烯-二乙烯基苯(PP-ST-DVB)纤维为母体,分别经磺化、氯甲基化和胺化反应制得强酸或强碱离子交换纤维;研究了在低湿条件下对酸碱有害气体的动态吸附性能。结果表明:强酸离子交换纤维(交换容量为2.92 mmol/g)对NH_3气体的穿透吸附量约为40.95 mg/g,高于Fiban K-1磺酸型离子交换纤维的穿透吸附量;强碱离子交换纤维对SO_2气体的穿透吸附量约为77.50 mg/g,是Fiban A-1强碱离子交换纤维的1.55倍,自制的强酸、强碱离子交换纤维可多次再生使用。

聚乙烯醇胺肟螯合纤维的合成及对钯的吸附

利用６０Ｃｏγ射线预辐照接枝和胺肟化反应合成了聚乙烯醇胺肟（ＰＶＡＡＯ）螯合纤维。预辐照剂量和接枝液的组成对接枝率，胺肟基团含量和吸附容量有影响。研究了ＰＶＡＡＯ螯合纤维对钯的吸附性能。

新型离子交换纤维的应用研究及展望

综述了离子交换纤维(IEF)在气相吸附、溶液中金属离子分离、农药有机废水处理以及高效催化剂等应用领域的研究现状,并展望了今后的研究发展方向。有关研究结果表明,IEF吸附量大、吸附速度快、容易脱附、分离工艺简便,是HF,HCl,H2S,SO2等有害气体的理想吸附材料;由于IEF比表面积大、交换速度快、再生时间短、易于洗脱等优点,也应用于污水中Cu2+、Co2+、Ni+等重金属离子和砷酸根离子的吸附,还是矿液中金、铂等贵金属离子的富集和多种过渡金属离子新型分离材料;IEF也可吸附废水中有机酸。此外,作为高效催化剂,IEF具有与反应物容易分离、反应后产物不必中和及水洗、腐蚀性小、选择性高、无副反应、无废液排放等优点。如何进一步提高IEF在中低湿度条件下的动态吸附性能,制备吸附功能基含量高、吸附量大、选择性好、对金属离子敏感性强的IEF等是目前研发的难题。

Thermodynamics of Cr(Ⅵ) adsorption on strong alkaline anion exchange fiber

Removal of Cr（VI） from aqueous solution by strong alkaline anion exchange fiber （SAAEF） was achieved using batch adsorption experiments. The effect of contact time, initial Cr（VI） concentration and pH was investigated. The results showed that the maximum adsorption capacity of SAAEF was 187.7 mg/g at pH=1.0. The adsorption capacity increased with Cr（VI） concentration but decreased with pH value when pH〉1.0. Adsorption isotherms at various temperatures were obtained. Langmuir, Freundlich, Dubinin-Radushkevich and Temkin models were adopted and the equilibrium data fitted best with the Langmuir isotherm. The constants of these models indicated that the adsorption process involved both chemisorption and physisorption. The values of thermodynamic parameters, including DH, DG and DS, suggested that the adsorption of Cr（VI） on SAAEF was a spontaneous, entropy-driven and endothermic process. Q（iso） was not a constant value, which indicated an inhomogenous energy distribution on SAAEF.

Effect of solution conditions on depression of chlorite using CMC as depressant

The effect of solution conditions on the depression of chlorite using CMC (carboxymethyl cellulose) as depressant was studied through flotation tests and adsorption measurements. Flotation and adsorption tests were first studied as a function of initial solution conditions. The results show that electrostatic repulsion between CMC molecules and chlorite surface hinders the approach of the CMC molecules to the chlorite surface and CMC adsorbs to a great extent at high ionic concentration (10-4 mol/L ions as opposed to 0 mol/L ions) or low pH (3 as opposed to 9). The enhanced adsorption density is attributed to the decreased electrostatic repulsion between CMC and mineral surface. The solution condition that yielded the lowest initial adsorbed amount (0 mol/L ions, pH 9) was used as a reference to investigate the response of the adsorbed CMC layer to a switch in solution conditions after adsorption. The two kinds of solution switches (reducing the solution pH or increasing ionic concentration) result in an increased depression effect of CMC on chlorite flotation, as a result of conformational change of CMC pre-adsorbed layer. The change in the flotation recovery of the CMC-coated chlorite following the solution switches is reversible.

Adsorption of Hg(Ⅱ) from aqueous solution using thiourea functionalized chelating fiber

A fast and selective adsorbent for Hg（ll） from aqueous solutions using thiourea （TU） functionalized polypropylene fiber grafted acrylic acid （PP-g-AA）, PP-g-AA-TU fibers, was characterized by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The adsorption behavior of the functionalized chelating fibers for Hg（Ⅱ） was investigated by static adsorption experiments, and the effects of some essential factors on adsorption of Hg（Ⅱ） were examined, such as pH, initial concentration, adsorption time, coexisting cations, and temperature, The results showed that the adsorptive equilibrium could be achieved in 10 min, and the equilibrium adsorption quantity of PP-g-AA-TU fibers was 20 times that of PP-g-AA fibers. The PP-g-AA-TU fibers showed a very high adsorption rate and a good selectivity for Hg（Ⅱ） over a wide range of pH. The adsorption isotherm can be well described with Langmuir model, with the maximum adsorption capacity for Hg（Ⅱ） up to 52.04 mg.g-1 and the removal of Hg（Ⅱ） more than 97%. The kinetic data indicate that the adsorption process is best-fitted into the pseudo-second-order model.

Equilibrium and Kinetic Study of Sericin Protein Absorption onto Anion-Exchangable Fibers

Silk is made of sericin and fibroin proteins. The sericin constitutes 20%- 30% of silk proteins and it covers the fibmin. Sericin is usually treated as impurity and removed during the process of degumming in dyeing and printing factories. However, sericin is a useful natural protein. In this paper, viscose auion-exchange fibers have been used to absorb seriein from waste water. The amount of adsorbed sericin into the viscose anion-exchange fibers at different temperatures and times has been studied. The study show that the anion-exchange fibers can adsorb sericin from the waste water. Furthermore, the equilibrium adsorption data show that the adsorption of sericin onto anion-exchange fiber fit the Freundlich isotherm at 25 1C and 50 ℃, and fit the Langmuir isotherm at 75 ℃.

Crosslinked chitosan nanofiber mats fabricated by one-step electrospinning and ion-imprinting methods for metal ions adsorption

The Pb(Ⅱ)ion-imprinting electrospun crosslinked chitosan nanofiber mats were fabricated by one-step electrospinning and ion-imprinting methods and their application as adsorbents for metal ions was also investigated.The resulting chitosan nanofiber mats were characterized by scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FTIR),X-ray photoelectron spectroscopy(XPS)and thermal gravimetric analysis(TGA).The Pb(Ⅱ)ion-imprinting electrospun crosslinked chitosan nanofiber mats were used as adsorbents for the removal of Pb(Ⅱ)ions from aqueous or acid solutions.The effects of p H values,contact time,content of crosslinker(glutaraldehyde)on Pb(Ⅱ)ions adsorption were studied.The results indicated that the Pb(Ⅱ)ion-imprinting electrospun crosslinked chitosan nanofiber mats had the highest adsorption capacity of 110.0 mg/g at p H 7.The kinetic study demonstrated that the adsorption of Pb(Ⅱ)ions followed the pseudo-second-order model.The equilibrium isotherm data showed that the Langmuir model was the most suitable for predicting the adsorption isotherm of the studied system.The Pb(Ⅱ)ion-imprinting electrospun crosslinked chitosan nanofiber mats had good adsorption selectivity,which illustrates the equilibrium adsorption capacity in the order of Pb(Ⅱ)>Cu(Ⅱ)>Zn(Ⅱ)>Cd(Ⅱ)>Ni(Ⅱ).The Pb(Ⅱ)ion-imprinting electrospun crosslinked chitosan nanofiber mats were stable and had good reuse ability.