Removal of boron from aqueous solutions by a hybrid ion exchange–membrane process

Abstract

For irrigation water boron is required for certain metabolic activities in plants. However, higher boron levels accelerate plant decay and expiration. Different plants can withstand different boron levels. For example, the optimal boron concentration range is 0.3–0.5 mg/L for citrus and grapes but is 0.5–0.75 mg/L for corn. Thus, the B-reduction in irrigation waters seems to be the most important challenge for environmental engineers as well as food producers. The WHO recommends a maximum concentration limit of boron of 0.5 mg B/L for drinking water. The general objective of this study was to explore the suitability and performance of the hybrid ion exchange–microfiltration process for boron removal from aqueous solutions. The efficiency of this novel separation technology for boron removal was investigated and compared to conventionally used ion-exchange processes. For experimental tests, commercially available chelating ion-exchange resins containing N-methyl glucamine groups were used. The effect of particle size of chelating resins on their kinetic performance for boron removal was compared using both processes.