壳聚糖纳微粒棉织物表面平衡吸附研究

Equilibrium Studies on the Adsorption of Chitosan Nano-/ Micro-particles onto Cotton Fabric Surfaces

通过热重分析法（TGA）系统地研究了不同温度下壳聚糖纳微粒（CNs）在棉织物表面的平衡吸附行为,并借助Langmuir、Freundlich及Dubinin-Radushkevich等温模型拟合曲线计算了吸附过程热力学参数.结果发现,三种等温吸附模拟均可对CNs棉织物表面平衡附着行为进行一定程度地描述,且在5～75℃下无交联剂吸附过程的标准吉布斯自由能变（△Go）、焓变（△H0）及熵变（△S0）均小于0,表明CNs在棉织物表面的附着行为是一个自发、放热且体系混乱度降低的过程.同时随着温度的降低,吸附过程的平均附着能（E）及△Go绝对值均不断增大,表明温度下降有利于吸附反应的进行,CNs与棉织物间的结合作用增强,且逐渐表现出化学吸附特性.

The equilibrium adsorption behaviors of the chitosan nano/micro-particles （CNs） onto cotton fabric surfaces were studied by Thermo Gravimetric Analysis （TGA） under different temperatures. Additionally, the fitting curves of Langmuir, Freundlich, and Dubinin-Radushkevich isotherm models were employed to calculate the adsorption thermodynamics parameters. The results suggested that the three isotherm models were also viable for de- scribing the equilibrium adsorption of CNs onto cotton fabrics. In addition, the negative values of the standard Gibbs free energy changes （ AG~） , enthalpy changes （ AH~） , and entropy changes （ AS~） of the adsorption at 5 75 ~C indicated that the process of CNs onto cotton fabric surfaces was exothermic and spontaneous with a decrease in randomness. Furthermore, the absolute values of the average energies （E） and △G0 of the adsorption process progressively increased with the decreasing temperature. This finding confirmed that more powerful interactions could be formed between CNs and cotton fabrics, and the adsorption process exhibit chemisorption properties under a low temperature.