羧甲基壳聚糖对金属离子吸附的研究进展

羧甲基壳聚糖及其改性产品的吸附性能主要体现在对各种金属离子的的吸附上.为了有选择性地吸附某些金属离子,人们通过修饰、交联、接技等方法对羧甲基壳聚糖进行了各种改性研究.文章综述了1992年以来羧甲基壳聚糖及其衍生物在金属离子吸附方面的研究进展.展望了吸附剂存重金属离子废水处理过程中的巨大优势和良好的发展前景.     

壳聚糖对金属离子吸附性能改性的研究进展

壳聚糖以其优良的理化性质和吸附特性在工业废水处理中已得到广泛的应用.目前对壳聚糖进行化学改性已经成为壳聚糖开发研究的热点.本文结合国内外研究成果对壳聚糖吸附金属离子性能的改性进行了评述和展望.     

改性壳聚糖/贝壳粉复合物对含重金属废水的吸附作用研究

介绍了重金属的污染危害性,分析了改性壳聚糖/贝壳粉复合物吸附工业废水重金属离子实验,研究了改性壳聚糖/贝壳粉复合物吸附性能,对工业废水处理有一定的参考价值。     

壳聚糖与凹凸棒土对金属离子吸附作用研究

研究了壳聚糖的提取、天然凹凸棒土的改性方法以及壳聚糖和改性凹凸棒土对Cu^2＋、Pb^2＋、Cd^2＋、Zn^2＋等金属离子的吸附作用。结果表明：壳聚糖和改性凹凸棒土的混合使用有利于降低成本,提高吸附效率。     

壳聚糖及其衍生物在重金属污染治理中的应用

壳聚糖是一种生物相容性和可生物降解的天然高分子有机聚合物，可以被改性和转化为各种壳聚糖衍生物。介绍了壳聚糖的制备方法、表征方法及其改性方法，阐述了壳聚糖及其衍生物在去除废水中重金属的应用研究进展。壳聚糖经过改性后显著提高了其表面的活性基团及其对金属离子的吸附效果。综述壳聚糖的相关信息以探索壳聚糖作为吸附剂去除废水中金属离子的潜力。     

改性壳聚糖材料处理难降解废水的研究进展及其应用

难降解废水严重影响着生态环境和人们的健康安全,因此研究如何有效处理难降解废水极为紧迫。改性壳聚糖具有吸附容量高、成本较低、不产生二次污染等特点,且在处理含染料、重金属离子、油等难降解废水的研究中表现出良好的吸附效果,因此得到相关人员的广泛关注。基于现有对改性壳聚糖的研究,介绍了壳聚糖和改性壳聚糖的性能和特点,着重分析了壳聚糖与无机物负载的物理改性方法和接枝共聚法、交联法、复合改性法等的化学改性方法,根据改性壳聚糖在处理难降解废水中的应用,总结了其吸附机理,指出了未来研究方向。     

壳聚糖及其衍生物去除金属离子的研究进展

壳聚糖具有来源广泛、无毒无害、功能基团丰富、化学活性强等特点,广泛应用于化工、环保、医药、食品等领域.围绕壳聚糖分子链上活性基团对金属离子的吸附能力,综述了壳聚糖及其衍生物在去除溶液中金属离子方面的研究工作及进展.介绍了对壳聚糖单体进行官能团置换或重组的化学改性法和改变壳聚糖物理形态的物理改性法,详细阐述了交联改性法、接枝改性法、磁化改性法、分子印迹法的基本原理、应用效果和优缺点,并对壳聚糖微球、壳聚糖膜的制备方法和材料性能进行了归纳.结合壳聚糖及其衍生物在制备和应用过程中存在的问题,提出了将化学改性和物理改性相结合制备新型印迹壳聚糖基聚合物,从而实现高效和选择性去除金属离子的研究方向.     

壳聚糖膜的改性及在废水处理中的应用进展

着重从提高壳聚糖膜吸附性能的角度出发,结合水处理机理,从表面改性、共混改性、纳米复合改性、离子印迹改性、接枝改性及其他改性方法六个方面综述了近年来改性壳聚糖膜的方向及其在处理染料废水、重金属离子废水及其他水生污染物中的应用进展。介绍了壳聚糖膜的成膜机理和制备方法,并探讨了膜的重复使用性。总结改性壳聚糖膜的优缺点,展望了壳聚糖膜的改性新方向。     

壳聚糖膜的改性及在废水处理中的应用进展

着重从提高壳聚糖膜吸附性能的角度出发,结合水处理机理,从表面改性、共混改性、纳米复合改性、离子印迹改性、接枝改性及其他改性方法六个方面综述了近年来改性壳聚糖膜的方向及其在处理染料废水、重金属离子废水及其他水生污染物中的应用进展。介绍了壳聚糖膜的成膜机理和制备方法,并探讨了膜的重复使用性。总结改性壳聚糖膜的优缺点,展望了壳聚糖膜的改性新方向。     

高岭土负载改性壳聚糖重金属吸附剂性能研究

壳聚糖是一种来源广泛、无毒、易降解的天然高分子材料,其分子中的羟基和氨基等官能团能与重金属离子进行螯合吸附。该研究充分利用高岭土高机械强度及多孔结构的特点,在其孔道结构中负载对重金属离子具有选择性吸附作用的改性壳聚糖,对解决传统改性壳聚糖在重金属污水处理中成本过高问题具有重要意义。通过超声和高温搅拌作用,在高岭土中负载改性壳聚糖合成新型的重金属吸附剂,幵针对其对污水中的Cu~(2+)、Mn~(2+)、Ni~(2+)、Pb~(2+)、Zn~(2+)等重金属离子的吸附效果、吸附性能及最佳吸附条件等进行了相应研究和应用前景展望。     

甲壳胺纤维的螯合性能

把甲壳胺纤维与CuSO4和ZnSO4的水溶液处理后,通过控制处理的时间可以使纤维吸附不同含量的金属离子。研究了纤维上的金属离子的含量对纤维的物理机械性能的影响。结果表明,吸附金属离子后,纤维的干强和湿强都有明显的增加。纤维上的金属离子可以被EDTA的水溶液洗去,从而可以使纤维重复地应用于废金属离子的回收利用。把甲壳胺纤维进行乙酰化处理后,纤维可以在固体状态下转化成甲壳素纤维。实验结果表明,乙酰化后的纤维失去了它们对金属离子的螯合性能,从而证明了甲壳胺纤维的螯合性能主要来自于纤维上的自由胺基团。     

羧甲基甲壳胺纤维对铜离子的吸附性能

为了提高甲壳胺纤维对重金属离子的吸附性能,用氯乙酸对纤维进行改性处理,在纤维的结构中引入羧甲基团后使纤维同时具有能结合重金属离子的胺基和羧酸基团。研究了改性后纤维在不同的改性程度、添加量、时间、温度、pH值等条件下对铜离子的吸附性能。结果表明:羧甲基化改性后的甲壳胺纤维对铜离子有很好的吸附性能。在同样的条件下,未改性的纤维对铜离子的吸附值为41.3mg/g,而改性后的纤维为79.4mg/g。经过羧甲基化改性的甲壳胺纤维对铜离子的饱和吸附容量可以达到148.1mg/g。     

磁性壳聚糖微球制备及在放射性水污染应用研究进展

磁性壳聚糖集成了壳聚糖螯合金属离子的能力和四氧化三铁的磁响应性,赋予了磁性壳聚糖吸附放射性污水中放射性金属离子能力,且具有可回收性和易再生性,使其在处理放射污水中效果显著.综述了纳米Fe3O4合成与磁性壳聚糖微球的制备方法,并讨论了在放射性污染水处理中的应用,最后展望了磁性壳聚糖研究趋势.     

壳聚糖及其衍生物对金属离子吸附研究进展

壳聚糖是一种天然高分子,分子中含有大量的氨基和羟基,对金属离子有很好的吸附能力.本文综述了壳聚糖及其衍生物对金属离子的吸附研究情况,并对其发展前景作了展望.     

Optical waveguiding and morphology of chitosan thin films

An investigation was made of the optical and waveguiding properties of thin films fabricated from solutions of chitosan-acetic acid (chitosan/HAc) and chitosan/HAc doped with rare-earth metal ions (Er⁺⁺⁺ or Nd⁺⁺⁺). For all three films, the refractive indices were approximately 1.5 and there was nearly no absorption in the range of 300 to 2700 nm. The optical loss in a waveguides was less than 0.5 dB/cm. Morphological observations disclosed that all the films possessed a dense and homogeneous amorphous structure with smooth surfaces. Extrinsic scattering, especially the scattering caused by surface impurities, was the dominating factor affecting the optical loss value. It is also interesting to note that for all the films, doped with rare-earth metal ions or not, the morphological characteristics were alike and the optical properties were similar. Doping rare-earth metal ions into chitosan thin films did not seriously influence optical waveguiding. This paper reports, we believe, the first study of chitosan films for optical applications. The experimental results demonstrate that chitosan and its derivatives are potential candidates for optical materials. © 1996 John Wiley & Sons, Inc.     

Postconsumer high‐density polyethylene/agave fiber foamed composites coated with chitosan for the removal of heavy metals

Composites of postconsumer high‐density polyethylene with agave fiber were prepared by single‐screw extrusion with azodicarbonamide as a foaming agent to increase the surface area; the composite pellets were coated with chitosan afterward. A chemical pretreatment was applied to the pellets to enhance the chitosan gel compatibility. The adsorption capacities of the composites coated with chitosan were evaluated for Cd(II) and Cu(II) removal from aqueous solutions. The coated composites were characterized by scanning electron microscopy, attenuated total reflectance infrared spectroscopy, and X‐ray photoelectron spectroscopy. Atomic absorption spectroscopy was used to measure metal uptake in batch adsorption studies. The results of this study demonstrated the composites' ability to immobilize chitosan on their surfaces and their capacity to adsorb metal ions. The equilibrium isotherms for Cd(II) and Cu(II) adsorption on the chitosan‐coated composites were described by the Langmuir model. This material represents an attractive low‐cost recycled material for adsorbing metal ions from polluted waters. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

火焰原子吸收法测定废水中Hg(Ⅱ)、Ni(Ⅱ)和Cr(Ⅵ)

采用了壳聚糖装柱法对金属离子进行吸附,研究了壳聚糖对Hg(Ⅱ)、Ni(Ⅱ)、Cr(Ⅵ)离子的吸附以及吸附时间、pH值和流速等对壳聚糖吸附的影响。通过最佳条件实验,用火焰原子吸收法测得重金属的含量并应用于工业废水的测定。     

A kinetic study of the thermal degradation of chitosan‐metal complexes

The thermal degradation of metal complexes formed by chitosan with Cu(II), Ni(II), Co(II), and Hg(II), at different metal concentrations, was studied by thermogravimetric analysis in a nitrogen atmosphere over the temperature range 25–800°C. The results indicate that thermal degradation of chitosan and chitosan‐metal ion complexes could be of one or two‐stage reaction. In the thermal degradation of chitosan with metal complexes, the temperature of initial weight loss and the temperature of maximum weight loss rate decrease. Fourier transform infrared spectroscopy was used to probe the interaction of chitosan with metal ions. The bands of ? N? H, ? C?O, ? C? O? C? groups of chitosan are shifted or change their intensity in the presence of metal. These changes in the characteristic bands are taken as evidence of the influence of metal ions on the thermal stability of chitosan. Broido's method was employed to evaluate the activation energies as a function of the degree of degradation. The presence of metal ions provoked a decrease in the thermal stability of chitosan, which became more marked when the concentration of metal was increased. The dynamic study showed that the apparent activation energy values of the main stage of the thermal degradation of chitosan‐metal complexes decrease as the strength of the polymer‐metal interaction increases. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Application of Chitosan Membranes in Separation of Heavy Metal Ions

Abstract

The authors present an application of chitosan membranes for the removal of heavy metal ions. Investigations covered membranes produced by phase inversion. Additionally, separation properties of acetylated membranes were tested. Low-viscous chitosan produced by the Sea Fisheries Institute—Poland was used in the experiments. The investigations were carried out for the transition metal ions Cr(VI), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), and Cd(II). A method for metal ions separation by means of chitosan membranes was proposed. The metal ions were complexed in the membrane during ultrafiltration of the solution. The separation ability of the membranes was investigated for individual metal ions and for a mixture. The effect of the pH of the solution on separation properties of membranes was determined. The concentration of metal ions was investigated by the method of inductively coupled plasma (ICP) atomic emission spectrometry. The investigations show the suitability of chitosan membranes produced by the phase inversion method for the removal of metal ions.