A chitosan-based bead was synthesized by crosslinking as well as sulfhydryl modification reaction and its removal ability of Pb²⁺, Cu²⁺ and Cd²⁺ was investigated. The test results showed that the crystal structure of chitosan was destroyed completely and the specific surface area was greatly increased after modification. The adsorption of Pb^{2+, Cu2+ and Cd2+ by the beads was} carried out at different pH, ionic strength, contact time and initial concentration and the maximum adsorption capacities were 273.7 mg/g, 163.3 mg/g and 183.1 mg/g, respectively. Furthermore, due to the large ion radius of Pb²⁺, its adsorption was seriously disturbed by other ions in the competitive adsorption process. Finally, the adsorption processes of Pb²⁺, Cu²⁺ and Cd²⁺ were well fitted by the Langmuir isotherm model and the pseudo second-order kinetics model, respectively. Combined with the results of X-ray photoelectron spectroscopy, chemical coordination is the main adsorption mechanism.

通过交联和巯基改性反应合成了壳聚糖基珠，并研究了其对Pb ²⁺、Cu ²⁺和Cd ^{2+ 的}去除能力。测试结果表明，改性后壳聚糖的晶体结构被完全破坏，比表面积大大增加。^珠对Pb 2 ^{+、Cu2+和Cd2+}的吸附在不同pH、离子强度、接触时间和初始浓度下进行，最大吸附容量分别为273.7 mg/g、163.3 mg/g和183.1 mg/g . 此外，由于 Pb ²⁺的大离子半径，其吸附在竞争吸附过程中受到其他离子的严重干扰。最后，Pb ²⁺、Cu ²⁺和Cd ²⁺的吸附过程分别由Langmuir 等温线模型和准二级动力学模型拟合。结合X射线光电子能谱的结果，化学配位是主要的吸附机制。