Development of a Novel Internal Electrolysis System by Iron Connected with Carbon: Treatment of Nitroaromatic Compounds and Case of Engineering Application

摘要

Nitroaromatic compounds (NACs), such as nitrophenol (NP) and nitrobenzene (NB), are common environmental contaminants because of their use as insecticides, pharmaceuticals, and industrial feedstock chemicals for dyes and so on (Zhang et al. 200724). Due to the toxic nature, the presence of NACs in wastewaters leads to the decline of conventional biological treatment efficiency. It is known that aromatic amines, the reduction products of NACs, are biodegradable (Agrawal and Tratnyek 19961; Yuan et al. 200622; Zhang et al. 200724). Therefore, the reduction in NACs to aromatic amines prior to biological process is critical for the successful treatment of wastewaters containing NACs. Zero-valent iron has been widely used as a reactive material in permeable reactive barriers for groundwater remediation since the mid-1990s (Gillham and O’Hannesin 19947; Korte 200110; Birke et al. 20073; Henderson and Demond 20078). It was also successfully applied in the pretreatment of industrial wastewaters to improve the biodegradability (Mantha et al. 200113; Mu et al. 200415). Contaminant removal by Fe0 was considered as a surface-mediated reaction via electron transfer or atomic hydrogen reduction in the 1990s (Matheson and Tratnyek 199414; Weber 199621). Recently, this mechanism was challenged by Noubactep (200716, 200817), who considered adsorption and coprecipitation as the fundamental removal mechanism of any species in a Fe0-H2O system. The redox sensitive specie may be subsequently (i) reduced by the electrons from Fe0, from structural FeII or H/H2, or (ii) oxidized by HO radicals in the oxide film.