胞外聚合物对Cu^(2+)、Cr^(3+)和Ni^(2+)的吸附性能研究

Study on Adsorption of Cu^(2+),Cr^(3+) and Ni^(2+) by EPS

以天津大学中水回用系统的膜生物反应器活性污泥为原料,采用热提法从中提取出了胞外聚合物(EPS)。经分析,该EPS的主要成分为蛋白质和多糖,含有的主要官能团为羧基、羟基和氨基。研究了EPS对Cu2+、Cr3+和N i2+三种重金属离子的去除效果,结果表明:EPS吸附Cu2+、Cr3+和N i2+三种重金属离子的适宜pH值分别为(3~5)、(4~6)、(4~6),适宜的投加比(EPS∶重金属离子)分别为(1.8∶1)、(1.6∶1)、(2∶1);EPS对Cu2+、Cr3+和N i2+的最大吸附容量分别为0.81、0.62、0.50 mg/mgEPS。EPS对不同重金属离子的吸附机理不同,对一种重金属离子吸附饱和后对其他重金属离子仍有吸附作用。

Heating extraction method was used to extract extracellular polymeric substances （EPS） from activated sludge coming from the membrane bioreactor （MBR） of wastewater reuse system for the bathing wastewater treatment in Tianjin University. The primary components of EPS are protein and polysaccharide, and the main functional groups are carboxyl, hydroxyl and amino. The study on the adsorption of Cu^2＋ , Cr^3＋ and Ni^2＋ shows that the proper pH values range from 3 to 5, from 4 to 6 and from 4 to 6 respectively, and the proper dosing proportions （mass ratio of EPS to heavy metal ions） are 1.8 ： 1, 1.6 ： 1 and 2 ： 1. The highest adsorption capabilities of Cu^2＋ , Cr^3＋ and Ni^2＋ by EPS are 0.81, 0.62 and 0.50 mg/mgEPS. The adsorption mechanism of different metal ions by EPS is not the same. Therefore, when the adsorption of one kind of metal ion reaches saturation, EPS can still adsorb the other kinds of metal ions.