电化学间接测量法研究谷胱甘肽在多壁碳纳米管和活性炭上的吸附

选取谷胱甘肽(GSH)作为小分子代表物,利用Cr(VI)与GSH的相互作用,即K2Cr2O7/H2SO4溶液加入GSH前后Cr(VI)还原峰电流值的差异,通过差分脉冲伏安法(DPV)的测定,可以间接测出GSH的含量.尝试将这种电化学间接测量法应用于研究多壁碳纳米管(MWCNTs)与商业活性炭(AC)对GSH的吸附行为.利用该方法可以确立GSH在二者的吸附量(Q)与吸附平衡浓度(Ce)的关系,绘制吸附等温曲线.根据Langmuir方程和Freundlich方程的拟合分析,证明了与商业活性炭相比,GSH在MWCNTs上的吸附更倾向Freundlich模型,即多分子层吸附.利用扫描电子显微镜(SEM)和透射电子显微镜(TEM)进行形貌表征,发现MWCNTs具有发达的堆积孔结构,有利于GSH小分子内扩散和吸附,与实验结果一致.

Electrochemical Indirect Measurement for the Study of Glutathione Adsorption on Multiwalled Carbon Nanotubes and Activated Carbon

Because of the chemical reaction between Cr(VI)ions and glutathione,the peak reduction current of Cr(VI)ions decreases while adding glutathione(GSH)into a K 2 Cr 2 O 7 /H 2 SO 4 solution.Thus the concentration of GSH can be detected indirectly by differential pulse voltammetry(DPV)analysis.This electrochemical indirect method was used to study the adsorption of GSH on multi-walled carbon nanotubes(MWCNTs)and activated carbon(AC),and can be used to determine the equilibrium relationship between GSH adsorption and its concentration.Unlike the result obtained from the active carbon,GSH adsorption on MWCNTs agrees better with that predicted by the Freundlich equation compared to that predicted by the Langmuir equation.The morphologies of MWCNTs and activated carbon were observed with scanning electron microscopy(SEM)and transmission electron microscopy(TEM).The abundance of aggregated pores in MWCNTs is beneficial for the diffusion and adsorption of small GSH molecules,suggesting that MWCNTs could be developed as an adsorbent for small molecular substances.