Bipolar membrane electrodialysis and ion exchange hybridizing for dilute organic acid solutions treatment

In this work, treatment of very dilute effluents of organic acids by means of an electro-membrane hybrid process is studied. Dilute organic acids effluents are generated by numerous processes. Converting such effluents into pure more concentrated fluxes is a key step in the valorization process. An experimental study has been performed to recover acetic acid by bipolar membrane electrodialysis (BMED). The experiments performed when coupling BMED and ion exchange have clearly demonstrated that hybridization reduces energy consumption. This improvement is due to the decrease of the electrical resistance of the diluted compartment thanks to the ionic conductivity provided by the resins. The effect of back diffusion on the current efficiency was also studied. In the case of acetic acid effluent treatment, investigation of the influence of the resin initial form showed that hydroxyl and acetate initial forms result in very close performances. It is therefore useless regenerating the resin bed.