Rapid and economic removal of N-nitrosodimethylamine
(NDMA) calls for advanced treatment strategies due to its mutagenic
and carcinogenic effects, small molecular size, high polarity, and
uncharged properties. Herein, a sequential Pd-modified polymeric ultrafiltration
(UF) membrane coated on a carbon paper substrate (CpPdM) was designed
for the complete elimination of NMDA in one single pass with low energy
consumption, with the synergetic processes of direct electrochemical
reduction and Pd-catalyzed hydrogenation. The hydrogen gas, produced
from direct electrochemical reduction, could trigger the Pd-catalyzed
hydrogeneration to improve the NDMA destruction performance. In addition,
the pre-rejection of interfering substances in the water matrix by
the frontmost UF layer hugely mitigates the fouling issues on the
electrode, thus improving the stability. Moreover, the flow-through
operation mode overcame the mass transfer limitation of traditional
electrodes in the flow-by mode (100% NDMA removal within 12.6 s of
residence time at −2.3 V), resulting in 2 orders of magnitude
enhancement in modified reaction kinetics. Furthermore, the combined
treatment of the CpPdM and nanofiltration was superior to the conventional
reverse osmosis process in NDMA removal and energy use. This work
is expected to provide a new strategy for developing an energy-efficient
advanced wastewater treatment system.