亚氨乙酸型螯合吸附材料IAA-PEI/SiO2对重金属离子的螯合吸附行为

将聚胺大分子聚乙烯亚胺(PEI)接枝于微米级硅胶微粒表面，制得接枝微粒PEI/SiO2，然后使氯乙酸与PEI大分子中的伯、仲胺基发生亲核取代反应，形成亚氨乙酸(IAA)型螯合吸附材料IAA-PEI/SiO2. 研究了IAA-PEI/SiO2对重金属离子的螯合吸附行为和吸附机理. 结果表明，由于亚氨乙酸基团与重金属离子之间的静电作用与配位螯合作用，IAA-PEI/SiO2对重金属离子可产生强的螯合吸附作用，对Ni2+的吸附容量可达1.4 mmol/g；吸附过程为放热过程；在可抑制重金属离子水解的pH范围内，pH值越高，吸附能力越强；IAA-PEI/SiO2对重金属离子的吸附容量顺序为Ni2+> Pb2+>Cu2+>Cd2+.

Chelating Adsorption Behavior of Imido-acetic Acid-type Composite Chelating Adsorption Material IAA-PEI/SiO2 for Heavy Metal Ions

Polyamine polyethyleneimine (PEI) was grafted onto micron-sized silica gel particles, obtaining the grafted particles PEI/SiO2. Subsequently, the nucleophilic substitution reaction between chloroactic acid and the first and secondary amino groups of PEI/SiO2 was performed, forming the imido-acetic acid (IAA)-type composite chelating adsorption material IAA-PEI/SiO2. The chelating adsorption characteristics of IAA-PEI/SiO2 to heavy metal ions, and the adsorption mechanism were investigated. The experimental results showed that IAA-PEI/SiO2 possesses strong adsorption ability for heavy metal ions by right of the synergism of electrostatic interaction and coordination chelating action between imido-acetic acid groups and heavy metal ions. The adsorption process of IAA-PEI/SiO2 towards heavy metal ions is exothermic. In the pH range, the hydrolysis of the heavy metal ions can be inhibited, the chelating adsorption ability of IAA-PEI/SiO2 to heavy metal ions increases with increasing pH value. The adsorption ability order of IAA-PEI/SiO2 to heavy metal ions is Ni2+>Pb2+>Cu2+>Cd2+.