Separation and Purification Technology, Vol.213, 587-598, 2019
Conversion and pre-concentration of SWRO reject brine into high solubility liquid salts (HSLS) by using electrodialysis metathesis
An electrodialysis metathesis (EDM) technology aimed at efficiently converting and pre-concentrating SWRO reject brine into high solubility liquid salts was proposed. In terms of process influence factors, effects of surface flow velocity, applied voltage and number of repeating units were investigated. Results showed that the applicable range of surface flow velocity should be set to 2.20-2.95 cm/s. 2 V per repeating unit seems appropriate for the operation. Increasing the number of repeating units in a certain region (>= 3) would be beneficial. For the ion migration analysis at optimized conditions, it was found that the ions leakage and co-ions migration were extremely weak. In the multiple batches pre-concentrating process, the TDS values of concentrating solutions gradually increased from 0 to about 200 g/L after 72 h, and scaling phenomenon was not found. This process thus provides a suitable way for producing high concentration liquid salts with high solubility feature.