硫脲基纳米螯合纤维对水溶液中Cd(Ⅱ)的吸附和密度泛函理论计算  

Experimental and DFT Studies on the Adsorption of Cd(Ⅱ) Ions from Aqueous Solutions by Nanofiber Modified Thiourea Groups

作　　者：李敏 赵纯[2] 冯钦忠 冯建[1] 孟晓静 LI Min;ZHAO Chun;FENG Qinzhong;FENG Jian;MENG Xiaojing(Department of Chemical Engineering,Chongqing University of Science and Technology,Chongqing 401331,China;College of Environment and Ecology,Chongqing University,Chongqing 400045,China;College of Resources and Environment,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]重庆科技学院化学化工学院,重庆401331 [2]重庆大学生态与环境学院,重庆400045 [3]中国科学院大学资源与环境学院,北京100049

出　　处：《高等学校化学学报》2021年第12期3680-3691,共12页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金(批准号:51708075);重庆市自然科学基金(批准号:cstc2020jcyj-msxmX0789);中国博士后基金(批准号:2021T140625,2020M673111)资助.

摘　　要：以聚丙烯腈为原料,利用静电纺丝技术和化学接枝制备得到硫脲基纳米螯合纤维,并用于水溶液中Cd(Ⅱ)的去除.结合样品的表征和密度泛函(DFT)理论计算结果,揭示了所制备纳米纤维材料对Cd(Ⅱ)的吸附机理.借助静态吸附和动态吸附实验,考察了硫脲基纳米螯合纤维对Cd(Ⅱ)的吸附性能.结果表明,纳米纤维吸附材料对Cd(Ⅱ)的最大吸附容量可达349.46 mg/g,吸附过程在90 min以内即可达到基本平衡.整个吸附过程符合准二级动力学模型和Langmuir等温吸附模型.硫脲基纳米螯合纤维吸附Cd(Ⅱ)的吸附机理为表面配位络合,增加纳米纤维表面硫脲基团的含量是提高吸附容量的重要途径.该吸附材料经6次循环使用后,最大动态吸附容量并未发生明显改变.Cadmium is a highly toxic metal,and Cd(Ⅱ)ions is a great threat to the ecological environment and human body. Herein,a new nanofiber modified thiourea groups was prepared using polyacrylonitrile(PAN)as the raw materials based on electrospinning and chemical grafting,which was used as an efficient adsorbent to remove Cd(Ⅱ)ions from aqueous solutions. Several characterized techniques,including Fourier transform infrared spectroscopy(FTIR),scanning electron microscopy(SEM),thermogravimetric analysis(TGA)and X-ray photoelectron spectroscopy(XPS)and density functional theory(DFT)theoretical calculations,were introduced to reveal the adsorption mechanism of FGTG(fiber modified by thiourea group)towards Cd(Ⅱ)ions. The adsorption behavior of Cd(Ⅱ)ions on the FGTG was investigated through batch and column experiments. The results show that the maximum uptake of Cd(Ⅱ)ions on the FGTG was 349.46 mg/g. The adsorption equilibrium was reached within 90 min and the adsorption isotherms fitted well with the Langmuir isotherm,and the obtained kinetic data support a pseudo-second order adsorption process. The adsorption mechanism of Cd(Ⅱ)ions on the FGTG is the surface coordination complexation,and it is an important way to improve the adsorption capa-city of Cd(Ⅱ)ions to enhance the content of thiourea groups in the adsorbent. Moreover,obvious change on the dynamic adsorption uptake of Cd(Ⅱ)ions was not been found even after six cycles. An adsorbent on Cd(Ⅱ)ions with low flow resistance was fabricated in this study and the adsorption mechanism was revealed by a series of characterized techniques and DFT.

关 键 词：镉离子 吸附 螯合纳米纤维 吸附机理 密度泛函理论 

分 类 号：O647.33[理学—物理化学]