Ammonium cation-mediated interfacial hydrogen-bond network reconstruction on dual-reaction-center interfaces for enhanced water self-purification

Wastewater containing high levels of ammonia nitrogen (NH 3 -N) poses a major challenge to catalytic purification because excessive ammonium (NH 4 + ) is generally considered to compete with emerging contaminants (ECs) and dissolved oxygen (DO) for interfacial adsorption and activation sites. Here, we convert livestock manure into a value-added dual-reaction-center (DRC) catalyst (GZHU-RPM), through sequential ball milling and cascade calcination. At the GZHU-RPM interface, NH 4 + mediates the reconstruct of the local hydrogen bond network of interfacial water, facilitating mass transfer and the spatially coupled oxidative cleavage of ECs at electron-poor centers and reductive activation of DO at electron-rich centers. Meanwhile, partial conversion of NH 4 + -derived nitrogen to nitrate (NO 3 - ) was detected, consistent with an oxidative pathway associated with the electron-poor centers. This NH 4 + -mediated interfacial reconfiguration enables the rapid removal of diverse antibiotics without externally supplied oxidants or energy input during treatment. Especially, under low-ammonia conditions, tetracycline (TC) removal increased by 10% relative to the control within 5 min. In real ammonia-rich wastewater, GZHU-RPM achieved 43% NH 3 -N removal and 30% COD removal within 60 min and maintained stable purification during 528 h of continuous-flow operation. Compared with conventional Fenton treatment, the GZHU-RPM system reduced life-cycle environmental impacts by more than 85% and treatment costs by 98%, demonstrating the sustainability of this waste-derived catalytic platform for ammonia-rich wastewater purification.