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壳聚糖与三聚磷酸钠离子交联后,再与环氧氯丙烷共价交联形成二次交联壳聚糖。该二次交联壳聚糖对Pb2+具有良好的吸附能力,FTIR图谱表明壳聚糖分子中的-OH和-NH2基团参与了吸附反应。吸附过程符合准二级动力学模型,随着温度的升高,速率常数k2增大而平衡吸附量qe下降。吸附平衡符合Langmuir吸附等温式,平衡常数KL和饱和吸附量qm随温度的增高而降低。热力学参数吉布斯自由能ΔG(,焓变ΔH°和熵变ΔS°均为负值,说明二次交联壳聚糖对Pb2+的吸附是放热和自发进行的。
Chitosan and sodium tripolyphosphate ion crosslinking, and then epichlorohydrin covalent cross-linked to form a secondary cross-linked chitosan. The secondary cross-linked chitosan has a good adsorption capacity for Pb2 +, and the FTIR spectrum indicates that the -OH and -NH2 groups in the chitosan molecule participate in the adsorption reaction. The adsorption process accords with the quasi-second-order kinetic model. As the temperature increases, the rate constant k2 increases and the equilibrium adsorption capacity qe decreases. The adsorption equilibrium is in accordance with the Langmuir adsorption isotherm. The equilibrium constant KL and the saturated adsorption capacity qm decrease with increasing temperature. The thermodynamic parameters Gibbs free energy ΔG (enthalpy change ΔH ° and entropy change ΔS ° are negative, indicating that secondary cross-linked chitosan adsorption of Pb2 + is exothermic and spontaneous.