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Recovery of rare metal by biosorption using algae and environmental improvement

利用藻类生物吸附回收稀有金属与环境改善

基本信息

批准号：
06555222
负责人：
KUWABARA Takao
金额：
$ 4.22万
依托单位：
Miyagi National College of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1996
项目状态：
已结题

项目摘要

1. Adsorption and elution of metal ion using packed column with algal powderMetal cations such as Cu, Ni, Co and Cd are adsorbed by packed algal layr at pH5-7, and eluted at pH 2. Therefore, aqueous solution with elevated metal ion concentration e.g. above 1000 ppm can be got from very dilute aqueous solution (e. g. 12ppm) via biosorption and elution. From this concentrated aqueous solution, metal can be electro-deposited through electrowinning.When powder of undaria pinnatifida or laminaria sp. is used for adsorption operations in packed column, aqueous solution cannot flow through the column because of the viscosity of the bulk. To oversome this trouble, aqueous paste of mixture of algal powder and a small amount of alginate salt powder is extruded into CaCl_2 aqueous solution through a nozzle. Whtn the noodle-like coagulated algal powder is packed in a column, the bulk has little viscosity, so the aqueous solution flows very well.The adsorbents made of algal powders exhibit excellent properties especially in elution oprtation. Therefore, amount of acidic reagent for elution can be reduced compared to the case of using ion exchange resin.2. Metal ion adsorption by algae and FTIR spectraBy FTIR spectra algae can be classified into two classes,(1) Algae which contain cellulose or alginate,(2) Algae which contain protein.When algal powder of class (1) above is contacted with acid aqueous solution at pH about 2 as pretreatment, IR absorbance of 1730 cm^<-1> is observed. This absorbance is considered to be the sign of the change in COOR partial structure in the algal powder.

1.藻粉填充柱对金属离子的吸附和洗脱在pH 5 -7的条件下，Cu、Ni、Co、Cd等金属离子被藻粉填充柱吸附，在pH 2的条件下被洗脱。因此，具有升高的金属离子浓度（例如高于1000 ppm）的水溶液可以从非常稀的水溶液（例如，G. 12ppm）。当裙带菜或海带的粉末用于填充柱中的吸附操作时，由于本体的粘性，水溶液不能流过柱。为了克服这个问题，将海藻粉和少量海藻酸盐粉的混合物的水糊状物通过喷嘴挤出到CaCl_2水溶液中。将面条状的藻粉凝聚体填充在柱中，由于其体积粘度小，水溶液流动性好，用藻粉制成的吸附剂具有优良的性能，尤其是在洗脱操作中。因此，与使用离子交换树脂的情况相比，可以减少用于洗脱的酸性试剂的量。藻类对金属离子的吸附和FTIR光谱根据FTIR光谱，藻类可分为两类，（1）含纤维素或藻酸盐的藻类，（2）含蛋白质的藻类，当将上述（1）类藻类粉末与pH约为2的酸性水溶液接触作为预处理时，观察到1730 cm-3的红外吸收<-1>。该吸光度被认为是藻类粉末中COOR部分结构变化的标志。