title: Macrocyclic receptors immobilized to monodisperse porous polymer particles by chemical grafting and physical impregnation for strontium capture: a comparative study.
abstract: Separation of strontium is of great significance for radioactive waste treatment and environmental remediation after nuclear accidents. In this work, a novel class of adsorbent (Crown-g-MPPPs) was synthesized by chemical grafting a macrocyclic ether receptor to monodisperse porous polymer particles (MPPPs) for strontium adsorption. Meanwhile, a counterpart material (Crown@MPPPs) with the receptor molecules immobilized to the MPPPs substrate by physical impregnation was prepared. To investigate how the immobilization manner and distribution of the receptors influence the adsorption ability, a comparative study on the adsorption behaviour of the two materials towards Sr(II) in HNO3 media was accomplished. Due to the shorter diffusion path and covalently-bonded structure, Crown-g-MPPPs showed faster adsorption kinetics and better stability for cycle use. While Crown@MPPPs had the advantages of facile synthesis and higher adsorption capacity, owing to the absence of conformational constraint to form complexation with Sr(II). Kinetic functions (Lagergren pseudo-first-order/pseudo-second-order functions) and adsorption isotherm models (Langmuir/Freundlich models) were used to fit the experimental data and examine the adsorption mechanism. On this basis, a chromatographic process was proposed by using Crown@MPPPs for an effective separation of Sr(II) (91%) in simulated high level liquid waste (HLLW).
authors.affiliation: Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing, PR China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Song
authors.affiliation: Department of Chemical Engineering, Laboratory for Advanced Materials, Tsinghua University, Beijing, PR China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Du
authors.affiliation: Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing, PR China.
authors.forename: Dachao
authors.initials: D
authors.lastname: Lv
authors.affiliation: Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing, PR China. Electronic address: yegang@tsinghua.edu.cn.
authors.forename: Gang
authors.initials: G
authors.lastname: Ye
authors.affiliation: Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing, PR China.
authors.forename: Jianchen
authors.initials: J
authors.lastname: Wang
mesh_terms: D000327:Adsorption; D043844:Crown Ethers / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D016062:Porosity; D013324:Strontium / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D043844:Crown Ethers; D011108:Polymers; D013324:Strontium
keywords: Adsorption; Chemical grafting; High level liquid waste; Macrocyclic ether; Porous polymer particles; Strontium