The heavy metal scavenger of Cu-2, Zn2 +, Cr3 +, Pb2 +, Cd2 + and other heavy metal ions in the strong negative electric field chelating wastewater generated by the polar group in the molecule of the molecule can produce insoluble flocculent precipitates. (Such as: EDTA, NH3, citric acid, etc.) can also play a full role, and has the advantages of high settling speed, high efficiency, energy saving, environmental protection, recycling, convenient and cheap, and solve the problem of heavy metal coexisting salt and complex salt At present, heavy metal capture agent has a one-time consumption of reagents, can not be recycled, toxic, slow settling, resulting in large volume of sludge, high water content, late filtration and other shortcomings.