Study of ultrasound, initial concentration and electrode material on the electrochemical removal of selenium and strontium

Abstract

Since high concentrations of selenium and strontium in water can potentially harm human health, various methods have been developed for their treatment. The objective of this paper was to validate previously published studies on the electrochemical removal of selenium and strontium, while also reducing the reactor operating time and using an ultrasound assisted process. After careful evaluation of the preliminary experiments, a combination of aluminum and iron electrodes was identified as the most suitable option for further investigation. The Design of Experiments approach was utilized to study the effects of ultrasound intensity (0%, 50%, 100%), operating time (2, 6, 10 minutes), applied current (2.5, 7.5, 12.5 A), and initial concentrations of selenium and strontium (1, 3, 5 mg L−1) on the sono-electrochemical removal of selenium and strontium from a synthetic solution. A modified ultrasonic bath, operating at 25 kHz, was used for all the experiments. The results showed that ultrasound and the initial selenium and strontium concentrations had no effect on the removal efficiency. The obtained reduced quadratic models predicted a removal efficiency of 93% for selenium and 34% for strontium under the optimal conditions, which included 10 minutes of operation and 12.5 A of current.