The adsorption and remove of heavy metal ions is still a real challenge in water treatment. Research for novel adsorbents with excellent properties is the most important issue in remediation of heavy metal pollution. Polyethyleneimine (PEI) is multi-functional polymer material. It was widely used in gene transfer

papermaking

catalysis

flocculant

dye- fixing agent

fiber modification

textile auxiliaries and ion exchange resin. The amine groups of PEI exist in primary

secondary and tertiary forms with a branching site at every 3~3. 5 nitrogen atom in any given chain segment

each with potential to be protonated. Thus

it has a high cationic charge density in acid solution and can form coordination complex with heavy metal ions in neutral or basic solution. As a novel sorbent

PEI has good hydrophilicity

high adsorption capacity

rapid chelating rate

good selectivity and it is also an environment friendly material. The character of PEI has attracted wide attention of researchers

and its applications in detection and adsorption separation fields of metal ions are developing. The adsorption properties of PEI were widely investigated. However

chelating mechanism of PEI was still limited. Mechanism study was summarized including: (1) Coordination process; (2) Electrostatic interaction; (3) Ion exchange effect. On the other side

applications on original PEI were much less due to its leachability and high costs. To solve this problem

research on PEI derivative was developed

including immobilization

grafting and modification of PEI. Moreover

combination of PEI with opto or electrical element to exploit novel photoelectric sensor was also discussed. The aim of this work is give a brief review of research on PEI as novel metal ions adsorbents

as well as its characteristic

adsorption and chelating mechanism. The modification and application of PEI was summarized with emphasis. This review provided a reference for broadening the potential application of PEI and developing new techniques for monitoring and treatment of heavy metal ions.