Speaker
Description
Column ion exchange technology has been used globally for many decades in the nuclear industries. Yet, several critical limitations to ion exchange column operation result in low throughputs, such as the limitation of adsorbent size to reduce frictional pressure drop issues [1] and the slow adsorption kinetics [2]. To tackle this issue, and create a more sustainable and efficient treatment solution, research was undertaken using tubular horizontal column ion exchange using agitated tubular reactors (ATRs). ATRs are intensified plug-flow reactors [3, 4], where high-rate horizontal shear is generated with inner agitator bar, decoupling mixing dynamics from the bulk flow. Prajitno et al. [5] conducted the experiments by comparing the performance of static vertical column ion exchange with the horizontal column ion exchange using ATR (Figure 1) on strontium removal using natural clinoptilolite zeolite with particle size ~ 300 m average as the adsorbents. The results showed that the ATR had ~30% increase in performance (in terms of both adsorption capacity and breakthrough values) and a 2-3 times faster relative flow rate than static vertical column. Improvements were due to enhanced mixing and adsorption kinetics from the lateral shear imparted in the ATR [5]. This can be an alternative solution for new remediation treatment plants, which can lead to more space efficient and sustainable process future. Current work is also investigating how such technologies may be embedded with other downstream unit operations for an integrated waste management approach.
References
1. Dyer, A., et al., The use of columns of the zeolite clinoptilolite in the remediation of aqueous nuclear waste streams. Journal of Radioanalytical and Nuclear Chemistry, 2018: p. 1-19.
2. Abusafa, A. and H. Yücel, Removal of 137 Cs from aqueous solutions using different cationic forms of a natural zeolite: clinoptilolite. Separation and Purification Technology, 2002. 28(2): p. 103-116.
3. Derksen, J.J., Mixing in an agitated tubular reactor. The Canadian Journal of Chemical Engineering, 2019. 97(2): p. 523-527.
4. He, Y., et al., Flow behaviour of an agitated tubular reactor using a novel dynamic mesh based CFD model. Chemical Engineering Science, 2020. 212: p. 115333.
5. Prajitno, M.Y., et al., Kinetic Studies of Cs+ and Sr2+ Ion Exchange Using Clinoptilolite in Static Columns and an Agitated Tubular Reactor (ATR). ChemEngineering, 2021. 5(1): p. 9.
