改性磁性壳聚糖微球对Cu2+、Cd2+和Ni2+的吸附性能

Fe3O4/ chitosan magnetic microspheres of 50 to 80 滋m were prepared using the inverse phase emulsion dispersion and chemical crosslinking technology, and then modified with ethylenediamine for use in the adsorption of heavy metal ions. The adsorption properties of the modified Fe3O4/chitosan toward Cu2+, Cd2+ and Ni2+ were investigated. It was found that the adsorption capacities of Cu2+ and Ni2+ increased with pH, and a maximum adsorption for Cd2+ occurred at pH=3. The saturated adsorption capacities calculated by Langmuir isotherms were 54.3 mg·g-1 for Cu2+, 20.4 mg·g-1 for Cd2+, and 12.4 mg·g-1 for Ni2+, respectively. The adsorption kinetics were well described by pseudo-second-order equation models. The experimental results showed that the Fe3O4/chitosan modified with ethylenediamine presented higher adsorption selectivity for Cu2+ than for Cd2+ and Ni2+ in all studied pH ranges.     

Preparation of Chitosan-coated Nylon Membranes and their Application as Affinity Membranes

Chitosan-coated nylon membranes which possess a large number of reactive groups of-CH2OH and -NH2 were prepared by coupling chitosan onto the nylon membrane. Then polylysine as ligand was also immobilized onto the composite membranes by 1, 1＇-carbonyl-diimidazole activation to prepare affinity membranes for bilirubin adsorption. The results showed that these membranes exhibited high binding affinity capacities for bilirubin and the adsorption isotherm fitted the Freundlich model well.     

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.     

PREPARATION AND CHARACTERIZATION OF NOVEL CHITOSAN DERIVATIVES: ADSORPTION EQUILIBRIUM OF IRON(Ⅲ) ION

The adsorption of Fe(Ⅲ)ions from aqueous solution by chitosan alpha-ketoglutaric acid(KCTS)and hydroxamated chitosan alpha-ketoglutaric acid(HKCTS)was studied in a batch adsorption system.Experiments were carried out as function of pH,temperature,agitation rate and concentration of Fe(Ⅲ)ions.The Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms and isotherm constants were determined.The Langmuir model agrees very well with experimental data.The pseudo-first-order and second-order kinetic models were used to describe the kinetic data and the rate constants were evaluated.The dynamical data fit well with the second-order kinetic model.The pseudo second-order kinetic model was indicated with the activation energy of 19.61 and 7.98 kJ/mol for KCTS and HKCTS,respectively.It is suggested that the overall rate of Fe(Ⅲ)adsorption is likely to be controlled by the chemical process.Results also showed that novel chitosan derivatives(KCTS and HKCTS)were favorable adsorbents.     

Microfluidic synthesis of thiourea modified chitosan microsphere of high specific surface area for heavy metal wastewater treatment

An improved biosorbent of thiourea modified chitosan microsphere(TMCM) with high specific surface,favorable mechanical strength and excellent adsorption performance had been synthesized via microfluidic technology. Polyethylene glycol was used as a significant component added in aqueous solution of chitosan to produce such microspheres through droplets forming, chemical crosslinking and pores creating. For the improvement of adsorption capacity, thiourea was considered as an excellent choice in increasing amino functional group by graft modification. The SEM, FTIR and EDS were employed to detect distinct features of TMCM. Copper(Ⅱ) was used to test the adsorption performance of TMCM. The experimental results indicated that TMCM exhibited higher adsorption capacity(q_e= 60.6 mg g_(-1)) and faster adsorption rate than that non-modified chitosan microsphere(NMCM).The adsorption kinetic was described well by the pseudo-second order kinetic model, which suggested that chemical adsorption along with electrons transferring was dominant in adsorption process.     

Adsorption of As(III) from aqueous solution based on porous magnetic/chitosan/ferric hydroxide microspheres prepared via electrospraying

Porous chitosan(CS)/magnetic(Fe3O4 )/ferric hydroxide(Fe(OH)3 ) microsphere as novel and low-cost adsorbents for the removal of As(Ⅲ) have been synthesized via the electrospraying technology by a simple process of two steps. Characterization of the obtained adsorbents was studied by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). The adsorption kinetics and equilibrium isotherms were investigated in batch experiments. The Langmuir, Freundlich isotherm and pseudo-second order kinetic models agree well with the experimental data. The adsorption of As(Ⅲ) onto CS/Fe3O4 /Fe(OH)3 microspheres occurred rapidly and reached adsorption equilibrium after about 45 min. The maximum adsorption capacity of CS/Fe3O4 /Fe(OH)3 microspheres, calculated by the Langmuir isotherm model, was 8.47 mg g-1 , which is higher than that of CS/Fe3O4 /Fe(OH) 3 prepared by the conventional method (4.72 mg g-1 ). The results showed that the microspheres had a high adsorption capacity for As(Ⅲ) and a high separation efficiency due to their microporous structure and superparamagnetic characteristics. Present research may eventually lead to a simple and low cost method for fabricating microporous materials and application for removal of arsenic from aqueous solution.     

An ion-imprinted polymer supported by attapulgite with a chitosan incorporated sol-gel process for selective separation of Ce(Ⅲ)

The surface ion-imprinting concept and chitosan incorporated sol-gel process were applied to the synthesis of a new attapulgitesupported polymer for selective separation of Ce(Ⅲ) from aqueous solution.The imprinting mechanism of prepared ion-imprinted polymer were discussed with the Characteristics of FT-IR and SEM.Results from the experiments of adsorption capacity and selectivity suggested that ion-imprinted polymer offered a fast kinetics for the adsorption of Ce(Ⅲ) under the optimum conditions. Its m...     

Preparation of a Cyclomaltoheptaose （p—cyclodextrin） Cross—linked Chitosan Derivative via Glyoxal or Glutaraldehyde

A cyclomaltohcptaose-β-cyclodextrin (β-CD) crosslinked chitosan derivative via glyoxal or glutaraldehyde was prepared. The structures of β-CD crosslined chitosan with glyoxal or glutaraldehyde were characterized by IR spectra. The surface morphology of the β-CD crosslinked chitosan particles was examined using a scanning electron microscope. The immobilization capacity of β-CD on chitosan was affected on the weight ratio of β-CD/chitosan,the utilization amount of crosslinking agent, the acidity of the reaction system and the temperature.The adsorption for nicotine indicated that the chitosan-β-CD was a good adsorbent.     

Dielectric study on membrane adsorption and release: Relaxation mechanism and diffusion dynamics

Dielectric monitoring of the adsorption or release process of salicylic acid (SA) by chitosan membrane shows that the dielectric spectra of the chitosan membrane/ SA solution systems change regularly in the adsorption or release process. By analyzing the regularity, a new mechanism for the relaxations is proposed. The concentration polarization layer (CPL) caused by SA adsorption or release is confirmed to be essential for the dielectric relaxations. The changes of the spectra with time are explained by account of the relationship between CPL properties and dielectric strength. Based on this relaxation mechanism, a theoretical method can be established to calculate dynamical parameters of inner structure of the adsorption or release systems from their dielectric spectra. Therefore, dielectric spec- troscopy is demonstrated to be a promising method for estimating interfacial distribution of ionic sub- stances and their binding to membrane in a non-invasive way.     

PREPARATION OF SURFACE ION-IMPRINTED ATTAPULGITE-SUPPORTED POLYMER AND ITS ADSORPTION BEHAVIORS OF Sr（II）

The surface ion-imprinting concept and chitosan incorporated sol-gel process were applied to the preparation of a new attapulgite-supported organic-inorganic hybrid polymer for selective separation of Sr（II） from aqueous solution. The prepared polymer was characterized with SEM, IR and XRD. The results showed that as a sorbent, it had good configuration and binding sites. Its adsorption behaviors for Sr（II） was investigated by FAAS and ICP-AES. The effects on adsorption capacities, including pH, quiescent time, and adsorbent amount were discussed, and the adsorption isothermal curve was obtained. Then the Kd a parameter estimating relative adsorbability, was conducted to study the selectivity towards Sr（II） of the prepared polymer. Under the optimum conditions, the ion-imprinted polymer offered a fast kinetics for the adsorption of Sr（II） and the maximum capacity was 12.9mg/g. The Kd and K parameters estimating relative adsorbability towards target ion, suggested that selective recognition of the ion-imprinted polymer towards Sr（II） was much higher than that of the non-imprinted polymer and attapulgite. Furthermore, the ion-imprinted polymer is of great regeneration capacity. The prepared functional polymer was shown to be promising for selective preseparation and enrichment of trace Sr（II） in environmental samples.     

氮杂冠醚接枝壳聚糖的合成及其对金属离子的吸附性能

本文利用壳聚糖Ｃ２位上活泼的氨基先与苯醛反应制备成保护氨基的Ｓｃｈｉｆｆ碱壳聚糖,再将含环氧基的氮杂冠醚接枝到壳聚糖的Ｃ６位上,制得含Ｓｃｈｉｆｆ碱的氮杂冠醚壳聚糖,随后使其在一定条件下脱去苯甲醛,合成了一种含氮杂冠醚功能基的新型壳聚糖衍生物,研究了其重金属离子Ｐｂ＾２＋,Ｃｕ＾２＋、Ｃｒ＾３＋、Ｃｄ＾２＋的静态吸附性能。结果表明,该吸附剂对重金属离子具有较强的吸附能力,在Ｐｈ＾２＋、Ｃｕ＾２＋、     

聚合物假冠醚研究 (III)新型聚合物氮杂假冠醚的合成与吸附性能

以苯酚为起始剂,用先聚合后功能基化和Na离子模板的简捷方法合成了一种新型聚合物-氮杂假冠醚。研究了其对金属离子的静态吸附性能,结果表明,聚合物对Na+ 和Ca2+离子具有良好的选择吸附性能,对浓度为0.026mol/L~0.028mol/L的Na+ 和Ca2+的静态吸附容量分别达2.54mmol/g和3.06mmol/g;通过红外光谱研究了聚合物及其与Na+ 和Ca2+的配合物的结构,结果表明,在吸附聚合物中,不仅-CH2OCH2-和-CH2NCH2-参与了配位, -CH2OH和PhOCH2- 亦不同程度地参与了配位。[( )-0.1( )] |     

羟基中环二胺接枝壳聚糖的合成与表征

以具有环氧活性基的壳聚糖与3-羟基-1，5-二氮杂环庚烷或3-羟基1，5-二氮杂环辛烷反应，合成了两种含羟基的氮杂冠醚壳聚糖衍生物，其组成及结构经元素分析，IR，X-射线粉末衍射及^13C NMR等方法确证。     

绵杆纤维的改性(Ⅱ)──氮杂冠醚化纤维素的制备及其对金属离子的吸附性能

经环氧活化的棉杆纤维素醚分别与3-羟基-1，5-二氯杂环庚烷和3-羟基-1，5-二氮杂环辛烷反应，制备了二种氮杂冠醚化棉杆纤维衍生物，测定了它们对金属离子的吸附性能及溶液pH值的影响。结果表明二者对Hg2 ，Cd2 有较好的吸附性能，对Cu2 的吸附-解吸-再吸附实验表明，二种氮杂冠醚化棉杆纤维衍生物具有重复使用的性能。     

杯芳烃-壳聚糖聚合物的合成与吸附性能

杯芳烃聚合物常常表现出优异的离子选择性识别性能,在离子交换与吸附、离子萃取与分离、离子传感器和离子色谱等方面有较好的应用前景,但这类聚合物的吸附能力一般较低。壳聚糖是甲壳素的脱乙酰衍生物,是具有广泛用途的天然生物高分子材料,其分子内有氨基和羟基,     

光敏离子载体丹磺酰基-单氮杂-18-冠-6的阳离子识别性质研究

以DNS－MAC（O5）为主体,利用其荧光性质研究了该物质在乙腈和水溶液中对阳离子Li^ ,Na^ ,K^ ,Mg^2 ,Ba^2 和Pb^2 的识别性质,由改进的B－H方程计算了主－客体配合物的稳定常数和识别敏感因子,结果表明,阳离子的电荷密度和阳离子与冠醚环空间的匹配程度是影响其识别性质的最重要的两个因素,DNS－MAC（O5）与阳离子配位时荧光光谱的变化主要受迭于阳离子的电荷密度,阳离子与DNS－MAC（O5）配位时不仅使这种离子载体的偶极矩增大,而且更有利于其实现光谱导分子内的电荷转移,所以激发态稳定性增加,荧光光谱红移,同时测定也该发光离子载体在乙腈和水中的荧光量子产率。     

Synthesis and metal ion complexation studies of proton-ionizable calix

A series of novel N-chromogenic calix[4]arene azacrown ethers were synthesized as selective extractants of potassium ion. 1,3-Alternate calix[4]arene azacrown ethers were prepared by reacting 25,27-dipropyloxy-26,28-bis(5-chloro-3-oxapentyloxy) calix[4]arenes with p-toluenesulfonamide in the presence of potassium carbonate. The coupling reaction of calix[4]arene azacrown ether with 2-hydroxy-5-nitrobenzyl bromide in the presence of triethylamine in THF gave the chromogenic calix[4]arene azacrown ether in moderate yield. These compounds show high potassium selectivity over other metal ions as shown by two-phase extraction, bulk liquid membrane, and 1H NMR studies on a ligand-metal complex. It is assumed that the OH of the chromogenic group attached on nitrogen can assist the complexation by encapsulation of the metal.     

球状壳聚糖负载噻二唑树脂的合成及其吸附性能

用苯甲醛保护胺基后,将2-氨基-5-巯基-1,3,4-噻二唑引入到大孔壳聚糖微球上,合成了亲水性的多孔球状吸附树脂(CTS-AMT)。 对比研究了CTS-AMT和母体微球(CTS)对Zn2+、Cu2+、Cd2+、Pb2+、Ag+和Hg2+的吸附性能。 结果表明,pH=5.0,T=298.15 K时,CTS-AMT树脂对上述金属离子的吸附在1.5 h内基本达到平衡,对金属离子Hg2+、Ag+和Pb2+的静态饱和吸附量分别为2.54、2.31和1.71 mmol/g。 在实验浓度范围内该树脂对Hg2+的吸附过程符合 Langmuir等温吸附模型。     

Mixed monolayers of alkylated azacrown ethers and palmitic acid at the air-water surface

The Langmuir films of two alkylated azacrown ethers at the air-water surface were characterized using surface pressure-area isotherms, ellipsometry, Brewster angle microscopy, and constant-area surface pressure relaxation. The azacrown ether molecules aggregate in the monolayer, which significantly stabilizes the film against dissolution. Mixed azacrown ether-palmitic acid monolayers were also characterized; results suggest that at high compression the two molecules interact repulsively. The influence of Cu(II) ions present in the aqueous subphase on the single components and mixed monolayer characteristics was also studied.     

含氮大环化合物的研究

总结十五年来在氮杂冠醚和大环多胺的合成和性质研究方面的主要成果：氮杂冠醚和大环多胺合成的方法学研究,氮杂冠醚和大环多胺的NMR研究,含氮杂冠醚结构单元的吲哚啉螺苯并吡喃类信息接受体的合成和性质研究,桥连环糊精二聚体的分子识别研究。