Hybrid alkali-acid urea-nitrate fuel cell for degrading nitrogen-rich wastewater

Electrochemical Urea Oxidation in Different Environment: From Mechanism to Devices

“…More importantly, the anodic potentials in some situations will even suppress the potentials of cathodic oxygen reduction (ORR), meaning the failure configuration of DUFCs system. Some efforts have been put forward to overcome this issue by constructing a hybrid alkali‐acid electrochemical device, where the alkaline anodic UOR and acidic cathodic ORR or other reduction reactions appears simultaneously with a critical bipolar membrane separator (BPM) equipped [92] . Although this asymmetrical strategy could significantly generate a higher theoretical cell voltage than those of the reported symmetrical DUFCs, a built‐in electric filed will actually form by the pH gradient at BPM interface, inducing a contact or interfacial potential usually involved between the junction zone of the two membranes [115] .…”

“…Also, the integrated N 2 RR j j UOR system could maintain a relative stability during 4 h chronopotentiometry electrolysis and the efficiency of NH 3 production after seven recycle tests. Furthermore, an integrated alkaline urea oxidation reaction (UOR) and acidic nitrate reduction reaction (NO 3 À RR) was established to simultaneously treat nitrogen-rich wastewater in a hybrid fuel cell through a functional bipolar membrane (more discussions seen in the next part), [92] also providing a potential cathodic counter reaction with UOR in a coupling electrolyzer but not broadly investigated ever.…”

Strategies for designing more efficient electrocatalysts towards the urea oxidation reaction

“…27 In conclusion, the UOR underpins these promising environmental and clean energy technologies such as urea-assisted water splitting, electrochemical treatment of urea-containing wastewater, and direct urea fuel cells. 28–30…”

Silvered TiO2 for Facet-Dependent Photocatalytic Denitrification

“…Nitrate (NO 3 – ) contamination of coastal water and groundwater, mainly arising from the increasing usage of nitrogenous fertilizers and inadequate treatment of disposed wastes, has become an urgent environmental issue and has caused great damage to organisms. , High concentration of NO 3 – is harmful to human health since it can be reduced to nitrite, which may cause “blue baby” syndrome and cancer. − The maximum concentration of NO 3 – in drinking water is 50 mg L –1 recommended by the World Health Organization. Therefore, it is an imperative requirement for efficient removal of the highly stable NO 3 – with a half-life of 2–3 years. , To date, numerous techniques, such as ion exchange, reverse osmosis, physicochemical treatment, and biological denitrification, have been developed for the reduction of NO 3 – . − However, these methods still suffer from the drawback of being time-consuming and hard to implement, intolerance to high concentration, and generation of secondary effluents.…”

“…) contamination of coastal water and groundwater, mainly arising from the increasing usage of nitrogenous fertilizers and inadequate treatment of disposed wastes, has become an urgent environmental issue and has caused great damage to organisms. 1,2 High concentration of NO 3 − is harmful to human health since it can be reduced to nitrite, which may cause "blue baby" syndrome and cancer. 3−5 The maximum concentration of NO 3 − in drinking water is 50 mg L −1 recommended by the World Health Organization.…”