Crown Ether-Immobilized Cellulose Acetate Membranes for the Retention of Gd (III).

Oana Steluta Serbanescu,Stefan Ioan Voicu,Augustin Semenescu,Madalina Oprea,Vijay Kumar Thakur,Andreea Madalina Pandele

doi:10.3390/polym13223978

Abstract

This study presents a new, revolutionary, and easy method of separating Gd (III). For this purpose, a cellulose acetate membrane surface was modified in three steps, as follows: firstly, with aminopropyl triethoxysylene; then with glutaraldehyde; and at the end, by immobilization of crown ethers. The obtained membranes were characterized by Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS), through which the synthesis of membranes with Gd (III) separation properties is demonstrated. In addition, for the Gd (III) separating process, a gadolinium nitrate solution, with applications of moderator poison in nuclear reactors, was used. The membranes retention performance has been demonstrated by inductively coupled plasma mass spectrometry (ICP-MS), showing a separation efficiency of up to 91%, compared with the initial feed solution.

Highlights

Gadoliniumbased salts have two main applications. They are used as contrast agents for clinical nuclear magnetic resonance (NMR) [8,9] and as moderator poison in nuclear reactors for fission reaction control [10], but small amounts of complexed Gd (III)-based solutions may remain in the brain, causing toxic effects [11,12], or need to be removed entirely from the nuclear reactor moderator system
To modify the membrane surface, we used our previous study about cellulose acetate membranes surface modification, in which the following steps were presented: hydrolysis of acetyl groups to increase the number of hydroxyl groups at the membrane surface; immobilization of aminopropyl triethoxysilane (APTES) and the reaction with glutaraldehyde (GA) at APTES amino groups; followed by crown ethers immobilization
APTES was used for the immobilization of magnetic particles [45], the compatibilization of nanocellulose with polyethersulfone [46] or polyvinyl alcohol [47], the hydrophobization of cellulose-based fabrics [48,49], or the reactive retention of dyes for wastewater purification [50,51,52,53]

Summary

Introduction

Researchers have a high interest in Gd (III), its applications and methods for its retention [1,2,3,4,5,6,7], the literature is inferior in methods for retaining this element and in methods for controlling this element’s concentration in solution. This is the case since the main applications of gadolinium-based salts are strictly regulated.

Methods

Results

Discussion

Conclusion