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林产化学与工业 ›› 2021, Vol. 41 ›› Issue (2): 24-32.doi: 10.3969/j.issn.0253-2417.2021.02.004

• 重点研发专栏 • 上一篇    下一篇

木质素离子印迹聚合物的制备及其对Cr(VI)吸附性能的研究

刘金昱, 刘瑞霞, 邓萍萍, 刘德乡, 郭盟, 吴志平()   

  1. 中南林业科技大学 材料科学与工程学院, 湖南 长沙 410000
  • 收稿日期:2020-10-10 出版日期:2021-04-28 发布日期:2021-05-08
  • 通讯作者: 吴志平 E-mail:wuzhiping02@163.com
  • 作者简介:吴志平, 教授, 硕士生导师, 主要从事精细化学品和木质素功能材料方向的研究; E-mail: wuzhiping02@163.com
    刘金昱(1996-), 男, 湖北仙桃人, 硕士生, 研究方向为木质素基吸附材料的制备及应用
  • 基金资助:
    国家重点研发计划资助项目(2017YFD0601000);中南林业科技大学研究生创新基金(CX20192004)

Preparation of Lignin-based Ion-imprinted Polymer and Its Adsorption Properties on Cr(VI)

Jinyu LIU, Ruixia LIU, Pingping DENG, Dexiang LIU, Meng GUO, Zhiping WU()   

  1. School of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha 410000, China
  • Received:2020-10-10 Online:2021-04-28 Published:2021-05-08
  • Contact: Zhiping WU E-mail:wuzhiping02@163.com

摘要:

以Cr(VI)为模板离子,N,N-亚甲基双丙烯酰胺为交联剂,将木质素磺酸钠与功能单体丙烯酰胺(AM)接枝共聚制备木质素离子印迹聚合物(L-ⅡP),通过单因素试验和正交试验优化了L-ⅡP的制备条件,利用FT-IR、SEM-EDS和孔径分析对L-ⅡP的结构进行了表征,采用准一级动力学方程、准二级动力学方程、Langmuir和Freundlich等温吸附方程对实验数据进行拟合,并探讨了L-ⅡP的重复利用性。FT-IR分析表明木质素磺酸钠和AM接枝共聚成功;SEM图可见L-ⅡP比木质素非离子印迹聚合物(L-NIP)具有明显的多孔结构;L-ⅡP孔径主要集中在3~5 nm和10~20 nm,是一种介孔材料。在模板离子10 mg、丙烯酰胺0.2 g、木质素磺酸钠100 mg和交联剂0.6 g的条件下,60℃下反应24 h制得的L-ⅡP吸附量最高,达到19.39 mg/g。室温下L-ⅡP最佳吸附条件为pH=2,Cr(VI)初始质量浓度为800 mg/L。L-ⅡP对Cr(VI)的吸附更符合准二级动力学方程,R2=0.980 1;且更符合Langmuir吸附等温线模型,最大吸附量(qm)为24.94 mg/g,R2=0.992,说明L-ⅡP对Cr(VI)的吸附是以化学吸附为主导的单分子层吸附。L-ⅡP在Cr(VI)/Cu(Ⅱ)和Cr(VI)/Cr(Ⅲ)混合溶液的吸附选择性系数分别为5.925和7,具有良好的选择性吸附性能。L-ⅡP具有较好的重复利用性能,5次吸附/解吸后,吸附量仍可达到最高吸附量的80%以上。

关键词: 木质素磺酸钠, 离子印迹聚合物, 选择性吸附, Cr(VI)

Abstract:

Lignin-based ion-imprinted polymer(L-ⅡP) was prepared via graft copolymerization of sodium lignosulfonate(SL) and acrylamide(AM) with using Cr(VI) as template ion, acrylamide as functional monomer, N, N-methylene-bis-acrylamide as crosslinker and ammonium persulfate as initiator. Then the L-ⅡP's structure and adsorption performance on Cr(VI) were studied. The preparation conditions of L-ⅡP were optimized by single factor experiment and orthogonal experiment. The structure of L-ⅡP was characterized by FT-IR, SEM-EDS and pore size analysis. The adsorption experimental data were fitted by quasi-first-order kinetic equation, quasi-second-order kinetic equation, Langmuir and Freundlich isothermal adsorption equation, and the reuse of L-ⅡP was discussed. FT-IR analysis showed that the grafting copolymerization of sodium lignosulfonate and AM was successful. SEM images showed that L-ⅡP had more porous structure than lignin non-ionic imprinted polymer(L-NIP). L-ⅡP was a kind of mesoporous material with pore size of 3-5 nm and 10-20 nm. When the mass of template ion, functional monomer, sodium lignosulfonate and crosslinker were 10 mg, 0.2 g, 100 mg and 0.6 g, respectively, and the reaction was performed at 60 ℃ for 24 h, the obtained L-ⅡP exhibited the best adsorption performance of Cr(VI). The optimum adsorption conditions at room temperature were pH value of 2 and initial concentration of Cr(VI) of 800 mg/L.The adsorption of Cr(VI) was described well with the pseudo-second-order model with R2 of 0.980 1, when L-ⅡP was used as absorbent. And the adsorption isotherm was consistent with the Langmuir model with qmof 24.94 mg/g and R2 of 0.992. The results indicated that the adsorption of Cr(VI) by L-ⅡP was a monolayer adsorption dominated by chemical adsorption. The selectivity coefficients of L-ⅡP for Cr(VI) of Cu(Ⅱ) and Cr(Ⅲ) were 5.925 and 7 respectively, indicating of its excellent selective adsorption properties. L-ⅡP had good reusability, after 5 times of adsorption/desorption, the adsorption capacity could still retain more than 80% of the maximum adsorption capacity.

Key words: sodium lignosulfonate, ion-imprinted polymer, selective adsorption, Cr(VI)

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