以乙二胺为改性剂、双氰胺和甲醛为原料，制备了改性脱色絮凝剂（EDA-DCDF），利用FT-IR、XRD和SEM对絮凝剂结构及形貌特性进行表征。考察了原料配比、絮凝剂投加量、废水初始pH、无机盐和表面活性剂等对染料脱色性能的影响。结果表明，改性双氰胺甲醛颗粒属无定形结构，相对于未改性双氰胺甲醛DCDF，改性后的EDA-DCDF获得了更好的脱色性能，对活性红195的最大脱色率可达到98.7%，明显高于DCDF。EDA-DCDF在酸性至微碱性条件下使用可获得良好的脱色性能，无机盐、表面活性剂对絮凝剂脱色性能产生了不同影响，在实验浓度范围内，EDA-DCDF展示了较好的抗盐性，而表面活性剂SDBS对脱色性能产生明显的负面影响。

EDA-DCDF, a modified decolorizing flocculant is synthesized by using dicyandiamide and formaldehyde as raw materials, and ethylenediamine as the modifying agent.The structure and morphological characteristics of EDA-DCDF are characterized by means of SEM, XRD and FT-IR.The influences of the molar ratio between raw materials, flocculant dosage, pH of initial wastewater, inorganic salts and surfactant on the decolorating ability of EDA-DCDF to dyestuffs are systematically investigated.According to experimental results, EDA-DCDF shows an amorphous structure, and exhibits higher decolorization efficiency compared to the unmodified DCDF.The decolorization rate of EDA-DCDF to reactive red 195 can reach 98.7%, apparently higher than that of DCDF.Under acidic to weak alkaline condition, EDA-DCDF can bring about high decolorization efficiency.Different impacts of inorganic salts and surfactant on the decolorization efficiency of EDA-DCDF are found.In the experimental concentration range, EDA-DCDF exhibits good resistance to inorganic salts, while surfactant SDBS affects adversely the decolorization performance of EDA-DCDF.