交联羧甲基纤维素吸附阳离子染料的动力学和热力学特性

摘要

以取代度为0.82的羧甲基纤维素钠[CMC(0.82)]为原料,通过固相合成法制备取代度为0.43的交联羧甲基纤维素[CCMC (0.43)],将其应用于对碱性品红(BF)和亚甲基蓝(MB)的吸附,分析吸附动力学和热力学特性.动力学研究结果表明,在CCMC吸附MB(BF)实验中,吸附90 min后,吸附基本达到饱和;吸附过程符合准二级动力学模型.液膜扩散为染料扩散的控速步骤.热力学研究结果表明,Langmuir吸附等温式拟合度更好,CCMC(0.43)对MB(BF)的吸附作用为单分子层吸附,且为优惠吸附,吸附过程是自发进行且为放热过程.用红外光谱(FTIR)和热重(TGA)等手段表征CCMC.%Using sodium carboxymethyl cellulose (CMC) with the degree of substitution of 0.82 as raw material,a crosslinked carboxymethyl cellulose (CCMC) with the degree of substitution of 0.43 [CCMC (0.43)] was prepared by solid phase heating reaction under the existence of acid,which was applied to basic fuchsin(BF) and methylene blue (MB) adsorption and adsorption kinetic and thermodynamic were analyzed.The results show that the adsorption quantity reached saturation after 90 min.The adsorption process was in accordance with pseudo-second-order kinetic model and liquid film diffusion was the controlling step.Langmuir isotherm fits better to the adsorption behavior,which is monolayer adsorption and favorable adsorption for CCMC (0.43),the adsorption process is spontaneous exothermic process.The structure of CCMC (0.43) was characterized by infrared spectroscopy (FTIR) and thermal gravimetric analyses (TGA).