Oxidation of N‐nitrosodimethylamine in a heterogeneous nanoscale zero‐valent iron/ H 2 O 2 Fenton‐like system: influencing factors and degradation pathway

BACKGROUND N‐nitrosodimethylamine ( NDMA ) is an emerging disinfection byproduct, which is also classified as a potential carcinogen and mutagen. Advanced oxidation processes based on hydroxyl radical (• OH ) have been suggested as an effective NDMA elimination method. This study focused on investigating the mechanism of oxidative degradation of NDMA using a nanoscale zero‐valent iron ( nZVI ) induced heterogeneous Fenton system. RESULTS The results show that nZVI was stable in the system. NDMA (≤1 mg L −1 ) was completely removed in 60 min under the following optimal conditions: initial pH =3.0, H 2 O 2 concentration =2 mmol L −1 and nZVI dose =56 mg L −1 . Major dissolved species (such as HCO 3 − , Cl − and humic acid) in a natural water matrix reduced the degradation rate of NDMA . During the degradation of NDMA , eight degradation intermediates were detected and confirmed, including methylamine ( MA ), dimethylamine ( DMA ), ammonia ( AM ), nitromethane ( NM ), hydroxyurea ( HU ), acetaldehyde ( AA ), NO 2 − and NO 3 − . Based on the identified intermediates, a tentative degradation pathway of NDMA in the nZVI / H 2 O 2 system was proposed. CONCLUSION Results indicate that nZVI as the catalyst used in the heterogeneous Fenton system is an effective alternative to remove NDMA . © 2016 Society of Chemical Industry