title: Facile preparation of highly hydrophilic, recyclable high-performance polyimide adsorbents for the removal of heavy metal ions.
abstract: To obtain high-performance adsorbents that combine excellent adsorption ability, thermal stability, service life and recycling ability, polyimide (PI)/silica powders were prepared via a facile one-pot coprecipitation process. A benzimidazole unit was introduced into the PI backbone as the adsorption site. The benzimidazole unit induced more hydroxyls onto the silica, which provided hydrophilic sites for access by heavy metal ions. By comprehensively analyzing the effect of hydrophilcity, agglomeration, silica polycondensation, specific surface area and PI crystallinity, 10% was demonstrated to be the most proper feed silica content. The equilibrium adsorption amount (Qe) for Cu(2+) of PI/silica adsorbents was 77 times higher than that of pure PI. Hydrogen chloride (HCl) was used as a desorbent for heavy metal ions and could be decomplexed with benzimidazole unit at around 300°C, which was lower than the glass transition temperature of PI. The complexation and decomplexation process of HCl made PI/silica adsorbents recyclable, and the adsorption ability remained steady for more than 50 recycling processes. As PI/silica adsorbents possess excellent thermal stability, chemical resistance and radiation resistance and hydrophilicity, they have potential as superior recyclable adsorbents for collecting heavy metal ions from waste water in extreme environments.
authors.affiliation: State Key Laboratory of Polymer Material and Engineering, College of Polymer Science and Engineering, Sichuan University, Chengdu 610065, PR China.
authors.forename: Jieyang
authors.initials: J
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Polymer Material and Engineering, College of Polymer Science and Engineering, Sichuan University, Chengdu 610065, PR China.
authors.forename: Yaxin
authors.initials: Y
authors.lastname: Zheng
authors.affiliation: State Key Laboratory of Polymer Material and Engineering, College of Polymer Science and Engineering, Sichuan University, Chengdu 610065, PR China.
authors.forename: Longbo
authors.initials: L
authors.lastname: Luo
authors.affiliation: State Key Laboratory of Polymer Material and Engineering, College of Polymer Science and Engineering, Sichuan University, Chengdu 610065, PR China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Feng
authors.affiliation: State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University, Chengdu 610041, PR China.
authors.forename: Chaoliang
authors.initials: C
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Polymer Material and Engineering, College of Polymer Science and Engineering, Sichuan University, Chengdu 610065, PR China. Electronic address: wx19861027@163.com.
authors.forename: Xu
authors.initials: X
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Polymer Material and Engineering, College of Polymer Science and Engineering, Sichuan University, Chengdu 610065, PR China. Electronic address: lxy6912@sina.com.
authors.forename: Xiangyang
authors.initials: X
authors.lastname: Liu
keywords: Adsorbents; Heavy metal; High performance; Polyimide; Recycle