| The technique of removing heavy metals nowadays had been summarized systematically in this paper. From the trends and the acceptability of the environment, a new kind of heavy metals capturing agent had been synthesized by cornstarch in detail. Otherwise, the research had been used chelating-ultrafiltration water treatment technique innovatively. Then the contradiction between the advantage of high efficiency of the soluble agent and the separation of the water after treatment had been solved perfectly. Also, the treatment conditions and the performances of removing seversal metals had been studied. There was a lot of contemporary instrument analysis methods had been used in the study, including MPT-AES, AAS, FTIR, Zeta micro-electropHoresis meter etc.. Then, the concentration of the heavy metals and pHysical or chemical properties, which the water had been treated before and after, had been crorrectly measured. Meanwhile, the mechanism of removing heavy metals also had been studied.1. The optimum reaction conditions of the synthesis of carboxymethyl starch were: basification temperature was 35°C, etherification temperature was 40°C, etherification time was 3 hours, ethanol concentration was 80%, basification time was 70min, the inputing dosage of sodium hydroxide during basification process was 50%, the ratio between starch and chloroaetic acid was 0.8, the ratio between sodium hydroxide and starch was 2.4, the concentration of starch was 4 mL/g. The optimum reaction conditions of the synthesis of crosslinked carboxymethyl starch were: cross-linked temperature was 35°C, etherification temperature was 40°C, etherification time was 3 hours, ethanol concentration was 80%, basification time was 70min, the inputing dosage of sodium hydroxide during basification process was 50%, the ratio between starch and chloroaetic acid was 0.8,the ratio between, sodium hydroxide and starch was 2.4, the concentration of starch was 4mL/g, the inputing of cross-linked agent was 0.04% to the mass of starch.2. The optimum conditions of the treatment of 10.00 mg/L lead imulation water sample by carbonmethyl starch were: pH=7.00, the inputing of capturing agent was 30.00 mg/L, the degree of substitution was 0.59, reaction time was 50min, the efficiency of removing of lead was 100%. The optimum conditions of the treatment of 10.00 mg/L nickle simulated water sample by cross-linked carboxymethyl starch were: pH=7.00, the inputing of capturing agent was 372.00 mg/L, the degree of substitution was 0.60, reaction time was 40min, the efficiency of removing of nickle was 96.4%.3. Under the condition of pH=7.00, it had been made use of chelating-ultrafiltration water treatment technique with cross-linked carboxymethyl starch in order to let the ions of copper, zinc, lead, cadmium water sample under the national criterion. The optimum dosages of usingcapuring agent were:i . The copper concentration was 20.00 mg/L, the degree of substitution was 0.60, reaction time was 40min, and the inputing of capturing agent was 90.00 mg/L.ii. The zinc concentration was 20.00 mg/L, the degree of substitution was 0.60, reaction time was 40min, and the inputing of capturing agent was 154.00 mg/L.iii. The lead concentration was 20.00 mg/L, the degree of substitution was 0.60;.reaction time was 40min, and the inputing of capturing agent was 70.00 mg/L.iv. The cadmium concentration was 20.00 mg/L, the degree of substitution was 0.60, reaction time was 40min, and the inputing of capturing agent was 546.00 mg/L.4. Under equal molar of copper, zinc, nickel, lead and cadmium, using chelating-ultrafilatration water treatment technique with cross-linked carbonmethyl starch to measure the order of capturing metals were Pb>Cu>Cd>Zn>Ni.5. There were competition between this new capturing agent and other materials in adsorbing heavy metals, such as acid and other chelating agent. Different kind of acid and chelating agent could give different desorption order. The desorption order which was used EDTA had been measured.That was Cd>Pb> Ni> Zn *?Cu.6. The mechanism of this new capturing agent was studied as follow: i . Chelating effect. ii .High polymer bridge effect, iii' Ions'exchange effect, iv. Web winding effect...
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