A novel macromolecule heavy metal chelating flocculant ISXA was prepared by grafting xanthate with chelating function and amide group with flocculation function to crosslinked starch. Through single factor experiment and orthogonal experiment, the optimal conditions for the preparation were concluded as follows: in starch-crosslinking phase, the mass ratio of epichlorohydrin to starch was 1.2 ∶ 10, the reaction temperature was 40 ℃, the pH value was 10.0; in xanthation phase, the mass ratio of carbon disulfide to starch was 6.3 : 10, the reaction temperature was 35 ℃, the pH value was 11; in acrylamide(AM)-grafting phase, the mass ratio of acry-lamide to starch was 1.5:10, the reaction temperature was 45℃, the pH value was 5. Through the FTIR and el-emental analysis, it was found that, ISXA had structures of xanthate and amide group simultaneously. The results of chelating flocculation test showed that, ISXA had good trapping and sedimentation efficiency in weak acid condition, when the pH value was 6.0, separately dosing 24, 90 and 200 mg/L of ISXA into the solution with Cu2+mass concentrations of 5, 20 and 50 mg/L respectively, the removal rates of Cu2+all reached as high as 99%; the flocs was dense and presented a good settleability under different pH conditions. The ISXA-Cu chelation sedi-ment was formed through the coordination reaction between sulfur atoms in xanthate and Cu2+. Adsorption bridg-ing and sweep coil trapping were main mechanisms of ISXA flocculation process.%将具有螯合功能的黄原酸基和酰胺基接枝到交联淀粉分子结构中，制备了高分子重金属螯合絮凝剂ISXA。通过单因素试验和正交试验获得了ISXA的最佳制备条件为：淀粉交联阶段，环氧氯丙烷与淀粉质量比为1.2∶10，反应温度为40℃， pH值为10；黄原酸化阶段， CS2与淀粉质量比为6.3∶10，反应温度为35℃， pH值为11；丙烯酰胺（AM)接枝阶段， AM与淀粉质量比为1.5∶10，反应温度为45℃， pH值为5。经FTIR、元素分析， ISXA具有黄原酸基及酰胺基结构。对Cu2+的螯合絮凝试验结果表明， ISXA在在弱酸性下有很好的捕集沉淀效果， pH值为6时，对于Cu2+质量浓度分别为5、20和50 mg/L的溶液， ISXA的投加量分别为24、90及200 mg/L， Cu2+去除率可达99%。絮体颗粒密实，在不同pH值下沉降性能良好。黄原酸基中的硫原子与Cu2+发生配位反应而形成ISXA-Cu螯合沉淀物，吸附架桥和网扫卷捕是ISXA絮凝反应的主要机理。
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