Kinetics and mechanisms of pH-dependent degradation of halonitromethanes by UV photolysis

► pH-dependent photodegradation kinetics and pathways of different HNMs were studied. ► The degradation rates of mono- and di-HNMs increased sharply at their pKa values. ► The quantum yield of HNM photolysis follows the order of TCNM > DBNM > DCNM > BNM. ► Degradation pathways could be different for protonated and deprotonated HNMs.