Anaerobic biotransformation of nitroanilines enhanced by the presence of low amounts of carbon materials

Abstract

Three microporous activated carbons -original (AC0), chemical oxidized with HNO3 (ACHNO3) and thermal treated (ACH2)-, and three mesoporous carbons - xerogels (CXA and CXB) and nanotubes (CNT)-, were tested on the biological reduction of o-, m- and p-nitroaniline (NoA) at a concentration above the half maximal inhibitory concentration (IC50) for a methanogenic consortium degrading a mixture of volatile fatty acids (VFA) containing acetate, propionate and butyrate. NoAs were only partially reduced in the absence of carbon materials (CM). Rates were dependent on the nitro group position, increasing in the order metha>para>ortho. CM lead to NoAs almost total reduction and at higher rates. With AC0 and ACH2, rates increased 3-fold, 4-fold and 8 fold for o-, m- and p-NoA, respectively.