Novel 3D Pd-Cu(OH)/CF cathode for rapid reduction of nitrate-N and simultaneous total nitrogen removal from wastewater.

Removal of NO is a challenging problem in wastewater treatment. Electrocatalysis shows a great potential to remove NO but selectively converting NO to N is facing a low efficiency. Here, a novel 3D Pd-Cu(OH)/CF cathode based electrocatalytic (EC) system was proposed that can rapidly and selectively convert NO to NH, and further convert to N simultaneously. The special designs for the system include: Cu(OH) nanowires were firstly grown on copper foam (CF) with excellent conductivity that features high specific surface area in enhancing NO absorption and conversion to NO. Then, palladium (Pd) with a superior photons activation capacity was doped on the Cu(OH) nanowires to promote the reduction of NO to NH. Then NH was quickly oxidized into N by active chlorine. Finally, total nitrogen (TN) could easily be removed completely via above exhaustive cycle reactions. The 3D Pd-Cu(OH)/CF cathode exhibits a 98.8 % conversion of NO to NH in 45 min with the reported highest removal rate of 0.017 cm min, which is 19.4 times higher than that of CF. The converted NH was finally exhaustively oxidized to N with a 98.7 % of TN removal in 60 min.