Cyclic coupling of photocatalysis and adsorption for completely safe removal of N-nitrosamines in water

The incomplete removal of N-nitrosamines in water through current degraded techniques and the carcinogenicity of N-nitrosamines call for alternative complete and safe removal approaches. Here, we describe a cyclic coupling process of photocatalysis and adsorption enabling N-nitrosamines in water thoroughly and safely removed. Among them, the immobilized TiO2/Ti photocatalyst degraded N-nitrosamines into primary and secondary amines up to 100% by attacking on nitrosyl nitrogen via center dot OH originated from its nanowire film morphology. Furthermore, the affinity of HY zeolite to primary and secondary amines led to efficient adsorption through corresponding to Lagergren adsorption rate equation of second order. And then the cyclic coupling process of photocatalysis and adsorption realized complete and safe removal of N-nitrosamines with various concentration ranging from 0.1 mM to 1 mM in water, significantly higher than the existing reports on the removal rate of Nnitrosamines and the formation potential of N-nitrosamines. This study will lead to new avenues for complete and safe eliminaton of hardly degradable hazardous substances in water.

Automated summary

A cyclic coupling process of photocatalysis and adsorption enables the complete and safe removal of N-nitrosamines in water. The immobilized TiO2/Ti photocatalyst degrades N-nitrosamines into primary and secondary amines, while HY zeolite exhibits efficient adsorption of these amines. This study offers new avenues for the complete and safe elimination of hardly degradable hazardous substances in water.