PNNL

Abstract

This study investigated the reaction pathway of 2,4-dinitroanisole (DNAN) on pyrogenic carbonaceous matter (PCM) to assess the scope and mechanism of PCM-facilitated DNAN hydrolysis. DNAN degradation was observed at pH 11.5 and 25°C with model PCM, graphite, whereas no significant decay occurred without PCM. Graphite exhibited a 1.78-fold enhancement toward DNAN decay at 65°C relative to the homogenous solution by lowering the activation energy for DNAN hydrolysis by 54.3±3.9%. Chemically modified activated carbon performed the best by reducing DNAN half-life from 185 to 2.5 days while maintaining its reactivity for ten cycles. Nitrite formation during DNAN decay confirmed denitration pathway whereas demethylation, the preferred pathway of homogeneous DNAN hydrolysis, produces 2,4-dinitrophenol (DNP). Denitration catalyzed by PCM is advantageous to demethylation because nitrite is less toxic than DNAN and DNP. These findings may be helpful in designing reactive adsorbent for in-situ remediation.