Comparative study on the treatment of simulated brominated butyl rubber wastewater by using bipolar membrane electrodialysis (BMED) and conventional electrodialysis (ED)

• The treatment of wastewater of brominated butyl rubber using two kinds of ED was firstly compared.
• The influences of operation parameters on the performance of two EDs were fully investigated.
• The economics were also investigated.

A large amount of wastewater containing sodium bromide (NaBr) is generated during the production of brominated butyl rubber. In our previous job, bipolar membrane electrodialysis (BMED) was used to regenerate hydrobromic acid (HBr) and sodium hydroxide (NaOH) from a simulated NaBr wastewater. To give a comparison with previously presented research paper, a desalinization of sodium bromide by using ED was also performed. The effects of operation parameters, such as current density, sodium bromide concentration, and initial acid and base concentrations in the concentrate, on desalinization were analyzed. In comparison, BMED has higher desalinization ratio and current efficiency, and much lower voltage drop and energy consumption. The process cost is estimated to be 0.82 $/kg NaBr for BMED and 1.01 $/kg NaBr for ED. Notably, BMED can also regenerate NaOH and HBr. Therefore, BMED will be more economically attractive and environmental benignity due to the regeneration of useful resource and prevention of secondary pollution.