Synthesis and Characterization of Cellulose Acetate Membranes with Self-Indicating Properties by Changing the Membrane Surface Color for Separation of Gd(III)

Oana Steluta Serbanescu,Florin Miculescu,Stefan Ioan Voicu,Andreea Madalina Pandele

doi:10.3390/coatings10050468

Oana Steluta Serbanescu, Florin Miculescu + Show 2 more

Open Access

https://doi.org/10.3390/coatings10050468

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Abstract

This study presents a new, revolutionary, and easy method for evaluating the separation process through a membrane that is based on changing the color of the membrane surface during the separation process. For this purpose, a cellulose acetate membrane surface was modified in several steps: initially with amino propyl triethoxysilane, followed by glutaraldehyde reaction and calmagite immobilization. Calmagite was chosen for its dual role as a molecule that will complex and retain Gd(III) and also as an indicator for Gd(III). At the contact with the membrane surface, calmagite will actively complex and retain Gd(III), and it will change the color of the membrane surface during the complexation process, showing that the separation occurred. The synthesized materials were characterized by Fourier transform infrared spectroscopy (FT-IR), thermal analysis (TGA-DTA), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy, demonstrating the synthesis of membrane material with self-indicating properties. In addition, in the separation of the Gd(III) process, in which a solution of gadolinium nitrate was used as a source and as a moderator in nuclear reactors, the membrane changed its color from blue to pink. The membrane performances were tested by Induced Coupled Plasma–Mass Spectrometry (ICP-MS) analyses showing a separation process efficiency of 86% relative to the initial feed solution.

Highlights

Gadolinium-based complexes and salts are used for two main applications: as contrast agent components for clinical and research magnetic resonance imaging (MRI) examinations [1,2] and poison for nuclear reactors in order to control the nuclear reaction [3]
This study presents a new, revolutionary, and easy method for evaluating the separation process through a membrane that is based on changing the color of the membrane surface during the separation process
At the contact with the membrane surface, calmagite will actively complex and retain Gd(III), and it will change the color of the membrane surface during the complexation process, showing that the separation occurred

Summary

Introduction

Gadolinium-based complexes and salts are used for two main applications: as contrast agent components for clinical and research magnetic resonance imaging (MRI) examinations [1,2] and poison for nuclear reactors in order to control the nuclear reaction [3]. Besides the fact that it is a highly toxic element, one of the biggest advantages of using this element in its currently known application is given by the practical situation that it cannot be present in environment, because contrast MRI agents are subject to very strict regulations, and the water that is used as the nuclear reactors’ moderator never goes into the environment due to the same strict regulations. From these reasons, the removal of Gd(III) from water is limited. Higher yields for retention can be obtained using mixed bed (MB) resin column consisting of Strong Acid Cation (SAC) resin and Strong Base Anion (SBA) resin [7], achieving a retention of 250 mg

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