Transformation of chloropicrin in the presence of iron-bearing clay minerals

Chloropicrin (trichloronitromethane, CP) reacted with reduced ferruginous smectite (SWa-1) in aqueous suspension. SWa-1 promoted CP-dechlorination to produce dichloro(DCNM) and chloronitromethane (CNM) with yields of up to similar to 80% within 30 min. The simultaneous formation of DCNM and CNM suggests that CP and SWa-1 surface participate in two electron-transfer pathways. A series of CP-adsorption and dechlorination rate constants in the presence of SWa-1 showed a strong correlation with the Fe(II) content of SWa-1 (r(2) = 0.96 and 0.98, respectively), {Fe(II)}. This study indicates that the oxidation state of structural Fe greatly alters surface chemistry and has a large impact on electron transfer during clay-organic interactions.