Catalytic impact of activated carbon on the formation of nitrosamines from different amine precursors

N-nitrosamines are emerging carcinogenic contaminants and can be generated from transformation of amines. Activated carbon (AC) materials with micro- and nano-porous structures are commonly used for extraction of nitrosamines in water, and for removal of micropollutants in water and wastewater treatment. Recent research demonstrated that AC materials may catalyze transformation of amine precursors to yield nitrosamines under environmentally relevant conditions. AC catalyzes the formation of nitrosamine primarily via two different types of reactions: (I) catalyzing nitrosation of amine with nitrite or nitrate to yield nitrosamine, and (II) catalyzing oxidation of amine in the presence of molecular oxygen and nitrogen to generate nitrosamine. The AC-catalyzed nitrosamine formation is highly influenced by AC's properties, amine precursors' structures and reaction conditions. Considering the widespread usage of AC in environmental and industrial applications, a better understanding of the catalytic impact of AC on nitrosamine formation is critical to minimize undesirable nitrosamine formation where co-existence of AC and amine precursors is encountered.