Electrodriven Selective Transport of Cs⁺ Using Chlorinated Cobalt Dicarbollide in Polymer Inclusion Membrane: A Novel Approach for Cesium Removal from Simulated Nuclear Waste Solution

Abstract

The work describes a novel and cleaner approach of electrodriven selective transport of Cs from simulated nuclear waste solutions through cellulose tri acetate (CTA)/poly vinyl chloride (PVC) based polymer inclusion membrane. The electrodriven cation transport together with the use of highly Cs+ selective hexachlorinated derivative of cobalt bis dicarbollide, allows to achieve selective separation of Cs+ from high concentration of Na+ and other fission products in nuclear waste solutions. The transport selectivity has been studied using radiotracer technique as well as atomic emission spectroscopic technique. Transport studies using CTA based membrane have been carried out from neutral solution as well as 0.4 M HNO3, while that with PVC based membrane has been carried out from 3 M HNO3. High decontamination factor for Cs+ over Na+ has been obtained in all the cases. Experiment with simulated high level waste solution shows selective transport of Cs+ from most of other fission products also. Significantly fast Cs+ transport rate along with high selectivity is an interesting feature observed in this membrane. The current efficiency for Cs+ transport has been found to be ∼100%. The promising results show the possibility of using this kind of electrodriven membrane transport methods for nuclear waste treatment.

Decreasing Seawater Desalination Footprint by Integrating Bipolar-Membrane Electrodialysis in a Single-Pass Reverse Osmosis Scheme

“…The higher the S i Na , the purer was the product NaOH. Notably, in accordance with the literature, 34 due to the higher ion transport rate (Figure 3a−c), caused by the higher driving force 37 for ion permeation, a higher voltage resulted in a lower S i Na . The CEM was almost non-selective (∼1.1, Table 3) for Na + over Ca 2+ at 24 V. As a result, a significant amount of Ca 2+ and Mg 2+ impurities (that could not be precisely quantified due to probable precipitation) were detected in the product NaOH.…”

“…Equation was used to calculate the transport selectivity for Na + over other cations (K + , Mg 2+ , and Ca 2+ ) from their respective time-dependent concentrations in the feed stream where S i Na is the transport selectivity for Na + over other cations “i” at time t 1 , F Na is the fraction (with respect to its initial amount in the feed) of Na + transported from the feed solution in time t 1 , and F Na is the fraction (with respect to its initial amount in the feed) of cation “i” transported from the feed in time t 1 .…”

“…Calculations. Equation 1 was used to calculate the transport selectivity for Na + over other cations (K + , Mg 2+ , and Ca 2+ ) from their respective time-dependent concentrations in the feed stream 34…”

Carboranes in the chemist's toolbox

“…Fig. 159 Supported liquid membrane (SLM) techniques are also being applied to the problem, and a recent report describes a flat sheet SLM process for 137 Cs extraction that employs the hexachlorinated cobalt dicarbollide anion in 40% n-dodecane/60% 2-nitrophenyloctyl ether. 154 Metal ion separation technology has been advanced by several recent modifications, including the development of membrane-based systems which require less solvent and generate less waste than solvent extraction or ion exchange methods.…”

“…With the PVC membrane, the process can be conducted in high acid concentrations (3 M HNO 3 ). 159 Supported liquid membrane (SLM) techniques are also being applied to the problem, and a recent report describes a flat sheet SLM process for 137 Cs extraction that employs the hexachlorinated cobalt dicarbollide anion in 40% n-dodecane/60% 2-nitrophenyloctyl ether. 160…”