Removal of boron by boron selective resin-filled electrodeionization

Abstract

Boron exists in the earth’s crust mainly in the form of borates or boric acid. Boric acid is a weak electrolyte and does not completely dissociate in aqueous solutions. Due to such features, it is not always possible to remove it efficiently by conventional water treatment technologies. In this work, it is the first time of the usage of boron selective resin-filled electrodeionization (EDI) to remove boron from aqueous solutions. While the experiments were carried out in constant voltage mode, however it was revealed that the applied potential and feed flow rate have significant effects on boron removal. On the other hand, variation in the electrolyte conductivity did not result in any notable changes in the boron removal efficiency. The removal performance of the boron selective resin-filled EDI cell was evaluated by calculation of flux, mass transfer coefficient, and power consumption. The results demonstrated that the feed flow rate has a significant effect on the mass transfer coefficient and flux of boron. The mass transfer coefficient of boron is found to be 7.78 × 10−4m∕s which is much higher than previously reported values in the literature. The energy consumption of boron selective resin-filled-EDI was in the range of 6.64 × 10−3–1.11 × 10 −1 Wh/g. The boron concentration in the solution decreased from 5 mg/L to 0.3 mg/L with a boron removal rate up to 94%.