Selective ammonia recovery from wastewater by SDS-AC based microfiltration membrane flow electrode capacitor deionization

Flow Electrode Capacitance Deionization (FCDI) has been frequently used for NH 4 + recovery from wastewater as a low-energy, high-efficiency electrochemical technique. However, issues such as high cost (mainly due to the use of ion-exchange membranes) and weak selectivity have limited the expansion of their applications. In this study, SDS-AC was prepared and applied in microfiltration membrane FCDI (MFFCDI) to recover ammonia (NH 4 + ). The material characterization results showed that the surfactant was stably loaded on the AC surface, and the adsorption capacity of modified AC for NH 4 + was greatly enhanced. During the recovery process, NH 4 + migrated to the electrode chamber and immobilized on the SDS-AC, while Na + migrated to the electrode chamber and then released to the desalination chamber due to co-ion repulsion. Based on this principle, selective recovery of NH 4 + was achieved (selectivity = 3.51). At the end of the recovery, more than 70 % of the NH 4 + was immobilized on the SDS-AC and the NH 4 + could be desorbed with NaOH. The results of the recycling experiments showed good stability of the SDS-AC-based MFFCDI system, and the recovery of food waste fermentation liquor demonstrated that the system could realize the selective recovery of NH 4 + from complex feed water. In summary, the SDS-AC-based MFFCDI technology has great potential for the application of NH 4 + recovery from wastewater. Although the scale of this study was limited to the laboratory stage, it still shows potential for application in engineering. In the future, larger scale applications in engineering will be carried out and the environmental and economic benefits of the technology will be assessed through a full life cycle analysis.