Anaerobic biodegradation of aniline under different electron accepting conditions

Abstract

Aromatic amines are important industrial chemicals. Due to their high toxicity and persistency in both water and soils, they are of environmental concern. Aniline is not biodegradable in normal anaerobic condition. A novel approach of anaerobic biodegradation coupled with selective redox mediators, is proposed. Different redox mediators, namely manganese dioxide, Ferric citrate, ferrous chloride and magnetic iron oxide nanoparticle were tested. Fe3O4 nanoparticles, with size of 10 nm, were shown as the best, leading to 98 % of aniline removal efficiency within 24 h of operation at 37 °C. Biodegradation of aniline followed a pseudo first order kinetic model. Products of reaction were identified by GC/MS, revealing that the biodegradation occurred via catechol pathway. Methanogenic activity tests suggest that an IC50 of aniline is ~10 mM and that Fe3O4 nanoparticles are not toxic on un-adapted biomass.