Schematic view of the experimental set-up
  • September 2023


  • Conference: 18th International Conference on Environmental Science and Technology CEST2023, 30 August to 2 September 2023, Athens, Greece
  • At: Athens, Greece


Katarina Licht

  • University of Zagreb Faculty of Civil Engineering
Ivan Halkijevic at University of Zagreb

Ivan Halkijevic

Hana Posavcic at University of Zagreb

Hana Posavcic

Goran Loncar at University of Zagreb

Goran Loncar

Abstract and Figures

3D numerical simulations and measurements on an electrochemical reactor were used to analyze the efficiency of strontium removal from water, with and without simultaneous ultrasound treatment. Ultrasound was generated using 4 ultrasonic transducers with an operating frequency of 25 kHz. The reactor used 8 aluminum electrodes arranged in two blocks. Strontium ions in water are modeled as particles characterized by a charge of 3.2•10-19 C and a diameter of 1.2•10-8 m. The numerical model was created in Flow-3D software using the basic hydrodynamic module, electrostatic module, and general moving objects module. The performance of the studied reactor variants by numerical simulations is defined by the ratio of the number of model strontium particles permanently retained on the electrodes at the end of the simulation period to the initial number of particles in the water. For the laboratory reactor, the effect of strontium removal is defined by the ratio of the homogeneous strontium concentration in the water at the end and at the beginning of the experiments. The results show that the use of ultrasound increases the effect of strontium removal from 10.3% to 11.2% after 180 seconds of water treatment. The results of numerical simulations agree with the results of measurements on a reactor with the same geometrical characteristics.


numerical model, electrochemical reactor, strontium

1. Introduction

Strontium (Sr) is a naturally occurring element found in many sedimentary rocks and some calcite minerals. Significant anthropogenic sources include industrial activities, fertilizers, and nuclear fallout (Scott et al., 2020). Sr concentrations greater than 1.5 mg L-1 in water can cause strontium rickets and other health problems in humans, especially in children (Epa et al., n.d.; Peng et al., 2021; Scott et al., 2020). Elevated Sr concentrations have been reported in drinking water worldwide, with concentrations as high as 52 mg L-1 in groundwater in the northern USA (Luczaj and Masarik, 2015; Peng et al., 2021; Scott et al., 2020). One of the possible remediation technologies for Sr is an electrochemical process (Kamaraj and Vasudevan, 2015). These processes are based on in-situ coagulant formation through the application of electric current to metal electrodes. The process consists of dissolution of the sacrificial anode, formation of hydroxide ions and hydrogen at the cathode, electrolyte reactions at the electrode surface, adsorption of coagulants on colloidal impurities and electrodes, and removal of the resulting flocs by precipitation or flotation (Mollah et al., 2001). One of the main drawbacks of the process is the polarization and passivation of the electrodes, which can be minimized by combining it with ultrasonication (Dong et al., 2016; Ince, 2018; Moradi et al., 2021). Ultrasonic cavitation can result in solute thermolysis and the formation of reactive species such as hydroxyl radicals and hydrogen peroxide (Mohapatra and Kirpalani, 2019). It also increases the mass transfer rates of solutes and enhances the surface properties of solid particles (Fu et al., 2016; Ziylan et al., 2013). The aim of this research is to evaluate the efficiency of the electrochemical (EC) batch reactor with and without the additional use of ultrasound (US), which is intended for the purification of water mainly contaminated with an increased concentration of Sr. The results of the 3D numerical simulations are verified by measurements in the laboratory EC reactor.


Dong, B., Fishgold, A., Lee, P., Runge, K., Deymier, P. and Keswani, M. (2016), Sono-electrochemical recovery of metal ions from their aqueous solutions, Journal of Hazardous Materials, 318, 379–387.

EPA. (2014), Announcement of Final Regulatory Determinations for Contaminants on the Third Drinking

Water Contaminant Candidate List. Retrieved from

Fu, F., Lu, J., Cheng, Z. and Tang, B. (2016), Removal of selenite by zero-valent iron combined with ultrasound:

Se(IV) concentration changes, Se(VI) generation, and reaction mechanism, Ultrasonics Sonochemistry, 29,

328–336. Ince, N.H. (2018), Ultrasound-assisted advanced oxidation processes for water decontamination, Ultrasonics Sonochemistry, 40, 97–103.

Kamaraj, R. and Vasudevan, S. (2015), Evaluation of electrocoagulation processfor the removal of strontium and cesium from aqueous solution, Chemical Engineering Research and Design, 93, 522–530.

Luczaj, J. and Masarik, K. (2015), Groundwater Quantity and Quality Issues in a Water-Rich Region: Examples from Wisconsin, USA, Resources, 4(2), 323–357.

Mohapatra, D.P. and Kirpalani, D.M. (2019), Selenium in wastewater: fast analysis method development and advanced oxidation treatment applications, Water Science and Technology: A Journal of the International Association on Water Pollution Research, 79(5), 842–849.

Mollah, M.Y.A., Schennach, R., Parga, J.R. and Cocke, D.L. (2001), Electrocoagulation (EC)- Science and

applications, Journal of Hazardous Materials, 84(1), 29–41. Moradi, M., Vasseghian, Y., Arabzade, H. and Khaneghah, A.M. (2021), Various wastewaters treatment by sono-electrocoagulation process: A comprehensive review of operational parameters and future outlook, Chemosphere, 263, 128314.

Peng, H., Yao, F., Xiong, S., Wu, Z., Niu, G. and Lu, T. (2021), Strontium in public drinking water and associated public health risks in Chinese cities, Environmental Science and Pollution Research International, 28(18), 23048.

Scott, V., Juran, L., Ling, E.J., Benham, B. and Spiller, A. (2020), Assessing strontium and vulnerability to

strontium in private drinking water systems in Virginia, Water, 12(4).

Ziylan, A., Koltypin, Y., Gedanken, A. and Ince, N.H. (2013), More on sonolytic and sonocatalytic decomposition of Diclofenac using zero-valent iron, Ultrasonics Sonochemistry, 20(1), 580–586.