【作者】 周利民；

【导师】 王一平；

【作者基本信息】 天津大学 ， 环境化工， 2007， 博士

【摘要】 磁性壳聚糖对金属离子有良好的吸附性能,适于大规模吸附,传质速率快,易于分离和改性。本课题考察了氨基化、硫基化及羧甲基化改性磁性壳聚糖对不同金属离子的吸附特性。从磁性吸附、模板吸附、纳米吸附和多组分吸附等多层次研究了改性磁性壳聚糖对金属离子的吸附特性。利用反相交联法制备磁性壳聚糖微球,并经硫脲改性（TMCS）和乙二胺改性（EMCS）。利用XRD、FTIR、TGA等对吸附剂进行了表征。考察了TMCS对Hg²⁺、Cu²⁺、Ni²⁺和EMCS Hg²⁺对UO2²⁺的吸附特性,考察了不同因素如接触时间、温度、pH值、金属离子初始浓度和搅拌速率的影响,以及进液流率、床层高度对Hg²⁺,Cu²⁺和Ni²⁺穿透曲线的影响。利用铜模板交联乙二胺改性壳聚糖磁性微球用于吸附水溶液中的Cu²⁺,考察了不同温度下Cu²⁺吸附平衡、吸附动力学、吸附热力学以及pH、离子强度以及共存离子(如Ni²⁺, Zn²⁺, Cd²⁺, Pb²⁺)对Cu-EMCS吸附Cu²⁺的影响。利用表面接枝法制备磁性羧甲基化壳聚糖纳米粒子（Fe3O4/CMC）,利用TEM、XRD以及FTIR等进行表征,考察了它对Pd²⁺和Pt²⁺的单组分吸附和双组分吸附特性。TMCS对Hg²⁺,Cu²⁺和Ni²⁺吸附动力学符合拟二级反应动力学模型。最大吸附容量（mg/g）分别为:Hg²⁺625.2; Cu²⁺66.7; Ni⁺15.3。随进液流率增大或床层高度下降,Hg²⁺,Cu²⁺和Ni²⁺穿透曲线变陡,且穿透点前移。临界床层高度Z₀（cm）分别为:Hg²⁺ 2.35;Cu²⁺ 3.41;Ni²⁺ 2.27。EMCS对Hg²⁺和UO₂²⁺的吸附动力学也符合拟二级反应动力学模型。pH<3时可选择性分离Hg²⁺和UO₂²⁺。饱和吸附容量qm（mmol/g）为:Hg²⁺2.14、UO2²⁺1.50。Cu-EMCS对Cu²⁺的吸附容量随温度升高而下降。用Avrami动力学等式能很好地拟合Cu²⁺吸附动力学数据,Cu²⁺吸附可分为1至2段动力学区域。与非模板磁性壳聚糖树脂相比,Cu-EMCS对Cu²⁺的吸附选择性明显提高。FTIR表明Cu-EMCS对Cu²⁺的吸附机理以主链-NH2基和-OH基络合Cu²⁺为主。Fe3O4/CMC对Pd和Pt的单组分吸附符合Langmuir模型和R-P模型,对Pd的亲和性优于Pt,最大吸附容量分别（mg/g）为:Pd 263.18;Pt 222.22;双组分吸附符合Langmuir多组分吸附模型。Pd和Pt之间存在竞争吸附。用0.5mol. L^-1硫脲脱附,脱附率较高（>75%）,但用5mol. L^-1氨水对Pd的脱附选择性较好。更多还原

【Abstract】 Magnetic chitosan has excellent adsorption performance toward many metal ions. It is suitable for large-scale adsorption and has the fast mass transferring rate. The adsorbent can be separated from the medium by a simple magnetic process. It also have a variety of surface functional groups for modification. In this paper, the magnetic chitosan particles were modified with amine groups, sulfur groups and carboxymethyl groups and their adsorption properties toward various metal ions were investigated. The adsorption properties of the modified chitosan magnetic particles were studied by the methods of magnetic adsorption, template adsorption, nano-adsorption and multi-component adsorption.Magnetic chitosan microspheres was prepared and then chemically modified with thiourea （TMCS） for use in the adsorption of metal ions. TMCS obtained was investigated by means of XRD, IR, magnetic properties and TG analysis. The adsorption properties of TMCS toward Hg²⁺, Cu²⁺ and Ni²⁺ were evaluated. Various factors affecting the uptake behavior such as contact time, temperature, pH and initial concentration of the metal ions were investigated using batch methods. The breakthrough curves of the uptake of Hg²⁺, Cu²⁺ and Ni²⁺ ions by TMCS at various flow rates and bed height of the adsorbents were investigated using column adsorption.Chitosan magnetic microspheres were prepared with the inverse-phase crosslinking method and modified with ethylenediamine. This adsorbent was characterized by XRD, IR, TGA, etc.The adsorption performance of the modified chitosan microspheres toward Hg²⁺ and UO₂²⁺ was investigated.The ethylenediamine- modified magnetic chitosan microparticles with Cu（II） as template ion （Cu -EMCS） were prepared and utilized as a novel adsorbent （Cu -EMCS） for the removal of Cu（II） from the aqueous solution. Cu-EMCS was characterized optical micrograph, IR spectra and TGA. The adsorption equilibrium and kinetics of Cu（II） andd the influence factors of the pH value, ions strength and co-existed ions such as Ni（II）, Zn（II）, Cd（II）, and Pb （II） ions the adsorption for Cu（II） ion were investigated.The magnetic carboxymethyl chitosan （Fe3O4/CMC） magnetic nanoparticles were prepared with a surface- tailing method. Chitosan was first carboxymethylated and then bound onto the surface of Fe3O4 nanoparticles. The obtained Fe3O4/CMC nanoparitcles were characterized by TEM、XRD and FTIR. The single and binary adsorption equilibrium and kinetics of Pd and Pt by Fe3O4/CMC were investigated.The results of adsorption of Hg²⁺,Cu²⁺ and Ni²⁺ ions by TMCS indicated that the adsorption kinetics follow the mechanism of the pseudo-second-order equation for all studied systems. The best interpretation for the equilibrium data was given by Langmuir isotherm and the maximum adsorption capacities were 625.2, 66.7 and 15.3 mg g-1 for Hg²⁺, Cu²⁺ and Ni²⁺ ions , respectively. The breakthrough time became earlier with the flow rate increasing or the bed height decreasing. The critical bed height for Hg²⁺, Cu²⁺ and Ni²⁺ ions were calculated as 2.35 cm for Hg²⁺,3.41 cm for Cu²⁺ and 2.27 cm for Ni²⁺, respectively . The adsorption kinetics of Hg²⁺ and UO2²⁺ ions by EMCS also follows the pseudo-second-order model. Selective seperation of Hg²⁺ and UO₂²⁺ was achieved at pH<3. The maximum adsorption capacity （qm） was 2.14 mmol/g for Hg²⁺ and 1.50 mmol/g for UO₂²⁺.The results of adsorption of Cu²⁺ ions by Cu-EMCS indicated that Cu²⁺ adsorption decreased with increasing temperature. Avrami kinetic equation was successfully fitted to the kinetic adsorption quantities. From this new equation, from one to two regions presenting distinct kinetic parameters were found. The results showed that the selectivity of Cu-EMCS for Cu（II） was greatly increased in relation to that of magnetic chitosan microparticles without Cu（II） template ion. The FTIR spectra reveals that Cu-EMCS coordinated with Cu （II） mainly through–OH groups and–NH2 group of the polymer chain.The results of adsorption of Pd and Pt by Fe3O4 /CMC nanoparticles indicated that the single-component adsorption isotherms were well fitted with Langmuir equations and R-P models. The saturated adsorption capacity was 263.18 mg/g for Pd and 222.22 mg/g for Pt, respectively. The bi-component isotherm adsorption data were well fitted with extended Langmuir models. The competition adsorption between Pd and Pt was observed. Desorption efficiency of more than 75% for both Pd and Pt was achieved using 0.5mol. L^-1 thiourea as eluant, while the higher selectivity was observed with 5mol. L^-1 ammonia.更多还原