Effect of MWCNT-modified graphite felts on hexavalent chromium removal in biocathode microbial fuel cells. Issue 85 (24th November 2017) - Wu, Xiayuan
Abstract : Oxidized MWCNT-modified graphite felt significantly improved Cr(vi ) removal in biocathode MFCs due to its affinity towards microbes and Cr(vi ). Abstract : Multi-walled carbon nanotubes (MWCNTs) and oxidative acid pretreated MWCNTs (oxidized MWCNTs, O-MWCNTs) were used to modify graphite felts as biocathode electrodes in Cr(vi )-reducing microbial fuel cells (MFCs). The results showed that both MWCNT modifications improved the efficiency of the Cr(vi )-reducing biocathode. In particular, the O-MWCNT modification led to a better performance due to the induced oxygen-containing functional groups on the O-MWCNTs. The O-MWCNT-modified graphite felt significantly promoted the Cr(vi ) removal and electricity generation of the MFC. The Cr(vi ) removal rate increased to 2.00 ± 0.10 mg L −1 h −1, which was 2.05 times higher than that of the unmodified control. The improvement was ascribed to the strong affinity and capacity of the O-MWCNTs towards microorganisms and Cr(vi ) ions. In addition, this study further confirmed that the ex situ biocathode acclimatization method could be an efficient way to screen potential biocathode materials for Cr(vi )-reducing MFCs.