▎ 摘　　要

The deposition of slag from a realgar tailing mine has caused serious land degradation to those farming and mining coexisting areas. However, nanomaterial-mediated biogeochemical arsenic cycle from arsenic-enriched soil was severely limited. In this study, the environmental impact of graphene oxide (GO) and reduced GO (rGO) on the speciation and mobilization of Fe/As from the flooding of arsenic-enriched soil was investigated. Regarding overall performance, rGO exhibited a more significant facilitation than GO on mediating microbial reduction of Fe(III)/As(V). The maximal levels of soluble Fe(II) and As(III) in the soil supplemented with acetate alone were 53.58 g.m(-3) and 9592 mg.m(-3) during the 50-day culture period. Nearly 1.37-fold and 1.15-fold of As(III) levels were released when amending with rGO acetate and GO acetate. Meanwhile, approximately 1.40-fold and 1.24-fold of Fe(II) levels were released under the same conditions. The underlying mechanism was correlated with the interactions between graphene and microbial activities. The properties of GO have been evolved through microbial reduction and eventually exhibited characteristics similar to rGO. Additionally, the application of graphene potentially altered the compositions of the microbial community and increased the abundance of some metal-reducing bacteria (e.g., Bacillus, Geobacter, and Desulfitobacterium), thereby favouring the dissolved organic matter bioavailability for bioreduction of Fe(III)/As(V). In addition, promotion of the electron transfer process of As(V)/Fe(III) reduction was predominantly responsible for the crucial role that rGO exhibited as a special redox-active mediator and electrical conductor. These findings might provoke more consideration of the integrated ecological effects of graphene and evaluate their environmental impact on land degradation.