An Efficient Method for Selective Desalination of Radioactive Iodine Anions by Using Gold Nanoparticles-Embedded Membrane Filter

Summary

An efficient method for the rapid and ion-selective desalination of radioactive iodine in several aqueous solutions is described by using gold nanoparticles-immobilized cellulose acetate membrane filters.

Abstract

Here, we demonstrate a detail protocol for the preparation of nanomaterials-embedded composite membranes and its application to the efficient and ion-selective removal of radioactive iodines. By using citrate-stabilized gold nanoparticles (mean diameter: 13 nm) and cellulose acetate membranes, gold nanoparticle-embedded cellulose acetate membranes (Au-CAM) have easily been fabricated. The nano-adsorbents on Au-CAM were highly stable in the presence of high concentration of inorganic salts and organic molecules. The iodide ions in aqueous solutions could rapidly be captured by this engineered membrane. Through a filtration process using an Au-CAM containing filter unit, excellent removal efficiency (>99%) as well as ion-selective desalination result was achieved in a short time. Moreover, Au-CAM provided good reusability without significant decrease of its performances. These results suggested that the present technology using the engineered hybrid membrane will be a promising process for the large-scale decontamination of radioactive iodine from liquid wastes.

Introduction

For several decades, huge amount of radioactive liquid wastes has been generated by medical institutes, research facilities, and nuclear reactors. These pollutants have often been a palpable threat to environment and human health^1,2,3. Especially, radioactive iodine is recognized as one of the most hazardous elements from nuclear plant accidents. For example, an environmental report on the Fukushima and Chernobyl nuclear reactor demonstrated that the amount of released radioactive iodines including ¹³¹I (t_1/2 = 8.02 days) and ¹²⁹I (

Protocol

1. Synthesis of Citrate-Stabilized Gold Nanoparticles

1. Wash a two-neck round-bottom flask (250 mL) and a magnetic stir bar with aqua regia, a mixture of concentrated hydrochloric acid and concentrated nitric acid in a 3:1 volume ratio.
   CAUTION: Aqua regia solution is extremely corrosive and may result in explosion or skin burns if not handled with extreme caution.
2. Rinse the glassware thoroughly with deionized water to remove residual aqueous acid.
3. Add 120 mL of chloroauric acid solution (HAuCl₄, 1 mM) to the two-neck round-bottom flask (250 mL) and heat it to reflux under constant stirring.
4. Add 12 mL of sodium....

Results

We have demonstrated simple methods for the fabrication of Au-CAM using citrate-stabilized AuNPs and cellulose acetate membrane (Figure 1a). The surface of Au-CAM was observed by SEM which showed that the nanomaterials were incorporated stably on the cellulose nanofibers (Figure 2). The nanoparticles incarcerated on the membrane were sustained stably and were not released from the membrane by continual washing wi.......

Discussion

In recent year, various engineered nanomaterials and membranes have been developed to remove hazardous radioactive metals and heavy metals in water based on their specific functionality in adsorption techniques^{25,26,27,28,29,30,31,32,}

Materials

Name	Company	Catalog Number	Comments
Hydrochloric acid	DUKSAN	1129
Nitric acid	JUNSEI	37335-1250
Chloroautic chloride trihydrate (HAuCl4·3H2O)	Sigma Aldrich	254169
Sodium citrate tribasic dihydrate	Sigma Aldrich	71402
[125I]NaI	Perkin-Elmer	NEZ033A010MC
Sodium chloride	Sigma Aldrich	S9888
Sodium iodide	Sigma Aldrich	383112
Sodium hydroxide	Sigma Aldrich	S5881
Lithium L-lactate	Sigma Aldrich	L2250	Synthetic urine
Citric acid	Sigma Aldrich	C1909	Synthetic urine
Sodium hydrogen carbonate	JUNSEI	43305-1250	Synthetic urine
Urea	Sigma Aldrich	U1250	Synthetic urine
Calcium chloride	JUNSEI	18230-0301	Synthetic urine
Magnesium sulfate	SAMCHUN	M0146	Synthetic urine
Potassium dihydrogen phosphate	JUNSEI	84185A1250	Synthetic urine
Dipotassium hydrogen phosphate	JUNSEI	84120-1250	Synthetic urine
Sodium sulfate	JUNSEI	83260-1250	Synthetic urine
Ammonium chloride	Sigma Aldrich	A9434	Synthetic urine
Sea water	Sigma Aldrich	S9148
1x PBS	Thermo	SH30256.01
Cellulose acetate membranes (pore size: 0.20 μm, diameter: 25 mm)	Advantec MFS	25CS045AS
Cellulose acetate membranes (pore size: 0.20 μm, diameter: 47 mm)	Advantec MFS	C045A047A
47 mm Glass Microanalysis Holders	Advantec MFS	KG47(311400)
Petri dish (50 mm diameter ´ 15 mm height)	SPL	10050
Gamma counter	Perkin-Elmer	2480 WIZARD2	Model number
UV-vis spectrophotometer	Thermo	GENESYS 10	Model number
Transmission electron microscopy	Hitachi	H-7650	Model number
Field Emission Scanning electron microscope	FEI	Verios 460L	Model number