Comparison of membrane-based acid-recovering processes under different driving forces using tailor-made proton permselective membrane

Membrane technologies should have great practical significance in the reclamation of waste acid. In this work, based on unique proton transfer mechanism, a proton permselective membrane is optimally prepared by self-assembly method and used for the waste acid reclamation by the membrane-based processes under different driving forces, such as pressure (PDMP), electric field (EDMP) and concentration gradient (CDMP). Above all, as-prepared membranes are understood from relevant perspectives, including chemical composition, structural morphology and fabricating conditions. Moreover, the effects of series of operating conditions on the corresponding work performances of waste acid recycling processes are explored. At last, a work performance index (WPI) is defined to compare the above membrane processes. Results indicate that PDMP has high processing capacity, whereas EDMP can recover acid with a high concentration. By contrast, CDMP is less energy-consuming. Accordingly, there is no single membrane process which can be regarded as the best choice because they all embrace their own strengths and weaknesses. That is, the combined use of multiple membrane processes and even coupling with other unit operations will be the highlight of future development.