胶原纤维固化杨梅单宁对Pb^(2+)、Cd^(2+)、Hg^(2+)的吸附

ADSORPTION OF METAL IONS BY MYRTAN TANNINS IMMOBILIZED ON COLLAGEN FIBER

以胶原纤维为基质,通过醛交联剂将杨梅单宁固化在胶原纤维上,制备固化杨梅单宁(IMT)吸附材料。研究该吸附材料对Pb2+、Cd2+和Hg2+的吸附性能。实验表明:该吸附材料对这 3种金属离子的吸附容量大小顺序为:Hg2+ >Pb2+ >Cd2+。吸附容量与pH值有关,pH值 7时,对Hg2+的吸附容量最大;pH值 3时,对Pb2+和Cd2+的吸附容量最大。在上述pH值条件下,当吸附剂用量为 0. 1g,金属离子初始浓度为 200mg/L、体积为 100mL时,IMT对Hg2+、Pb2+、Cd2+的平衡吸附容量分别为 198、87和 24mg/g。通过研究温度对吸附平衡的影响以及吸附动力学,发现IMT对Hg2+的吸附主要为化学吸附,对Pb2+的吸附可能包含物理吸附和化学吸附,对Cd2+的吸附以物理吸附为主,这与金属离子在水溶液中的状态有关。当水体中同时存在Hg2+和Pb2+时,IMT对每种金属离子的平衡吸附容量几乎不受其它金属离子的影响,即可以用于同时吸附除去这些金属离子。

Using collagen fiber as matrix,the immobilized myrtan tannins (IMT) was prepared through aldehyde cross-linking reaction.As a novel adsorbent,its abilities of recovering Pb^(2+ ),Cd^(2+ )and Hg^(2+) from waste water were studied.(Experiments) showed that the sequence of adsorption capacities of the metal ion on the adsorbent were Hg^(2+ )>Pb^(2+ )>Cd^(2+).The adsorption capacity was related to pH value of solution.The highest adsorption capacity of Hg^(2+) (occurred) at pH value 7.0,whilst those of Pb^(2+) and Cd^(2+) occurred at pH value 3.0.Under the optimized pH value conditions,the equilibrium adsorption capacity of Hg^(2+) on the IMT was 198 mg/g and those of Pb^(2+) and Cd^(2+) were 87 and 24 mg/g respectively,when adsorption process was undertaken by using 0.1 g IMT and 100 mL metal ion solution with initial concentration 200 mg/L.The characteristic of adsorption kinetics and the influence of temperature on (adsorption) isotherms were investigated,both indicated that Hg^(2+) is mainly chemically adsorbed by the IMT,the (adsorption) of Pb^(2+) includes chemical and physical processes and that of Cd^(2+) is primarily due to physical association.These are related to the forms of metal ions in aqueous solution. It was also found that,when more than one metal ion existed in aqueous solution,the equilibrium adsorption capacity of each ion was not affected by others,implying that the IMT adsorbent is effective in simultaneous removal of these ions.