Effective Control of N-Nitrosamines Formation from Water by Layered Double Oxide/Biochar Spheres: Research on the Adsorption of Precursors

Nitrogenous compounds in raw water favor the formation of N-nitrosamines during disinfection and pose serious health concerns to consumers. Here, we prepared layered double oxide-biochar sphere nanocomposites (LDO/BSs) to control the formation of trace N-nitrosamines from different source waters. The adsorption capacity of six representative aliphatic secondary amines can be significantly enhanced by LDO/BSs in water mainly through complexation between N in the skeleton of pollutants and Ni of LDO/BSs. Importantly, LDO/BSs can obviously decrease the levels of potential N-nitrosamine precursors, such as organic nitrogen content (67%–76%) and fluoresceous-dissolved organic matter content (78% removal of protein-like component and 70% removal of humic-like component) in source waters from four drinking water treatment plants. These reduced the N-nitrosodimethylamine formation potential from 30.9 to 12.6 ng/L in source waters treated with LDO/BSs, which was lower than that in the finished water from drinking water plants. Regeneration of the material can be achieved by peroxymonosulfate activation. This study provides a new strategy to effectively control disinfection byproducts in water, protecting human health and the ecological environment.