Electrochemically selective ammonium recovery from wastewater via coupling hydrogen bonding and charge storage

Electrochemical ammonium (NH4+) storage (EAS) has been established as an efficient technology for NH4+ recovery from wastewater. However, there are scientific difficulties unsolved regarding low storage capacity and selectivity, restricting its extensive engineering applications. In this work, electrochemically selective NH4+ recovery from wastewater was achieved by coupling hydrogen bonding and charge storage with self -assembled bilayer composite electrode (GO/V2O5). The NH4+ storage was as high as 234.7 mg N g(-1) (> 10(2 )times higher than conventional activated carbon). Three chains of proof were furnished to elucidate the intrinsic mechanisms for such superior performance. Density functional theory (DFT) showed that an excellent electron -donating ability for NH4+ (0.08) and decrease of diffusion barrier (22.3 %) facilitated NH(4)(+ )diffusion onto electrode interface. Physio- and electro-chemical results indicated that an increase of interlamellar spacing (14.3 %) and electrochemical active surface area (ECSA, 388.9 %) after the introduction of GO were responsible for providing greater channels and sites toward NH4+ insertion. Both non-ionic chemical -bonding (V-5(+)=O center dot center dot center dot H, hydrogen -bonding) and charge storage were contributed to the higher capacity and selectivity for NH4+. This work offers underlying guideline for exploitation a storage manner for NH4+ recovery from wastewater.