Microbial fuel cell (MFC) technology is utilized to treat hexavalent chromium (Cr(VI)) from wastewater and to generate electricity simultaneously. The Cr(VI) is bioelectrochemically reduced to non-toxic Cr(III) form in the presence of an organic electron donor in a dual-chambered MFC. The Cr(VI) as catholyte and artificial wastewater inoculated with anaerobic sludge as anolyte, Cr(VI) at 100 mg/L was completely removed within 48 h (initial pH value 2.0). The total amount of Cr recovered was 99.87% by the precipitation of Cr(III) on the surface of the cathode. In addition to that 78.4% of total organic carbon reduction was achieved at the anode chamber within 13 days of operation. Furthermore, the maximum power density of 767.01 mW/m2 (2.08 mA/m2) was achieved by MFCs at ambient conditions. The present work has successfully demonstrated the feasibility of using MFCs for simultaneous energy production from wastewater and reduction of toxic Cr(VI) to non-toxic Cr(III). © IWA Publishing 2015.

Praveena Gangadharan

Department of Civil Engineering

I.M. Nambi

Fulltext

Indian Institute of Technology Palakkad&nbsp;(IIT Palakkad or IIT PKD) is a public autonomous&nbsp;engineering&nbsp;and&nbsp;research&nbsp;institute located in&nbsp;Palakkad,&nbsp;Kerala. It was&nbsp;one of the five new&nbsp;IITs&nbsp;proposed in the&nbsp;2014 Union budget of India. The campus was inaugurated on 3 August 2015. The institute has 94 faculty, 978 students, and 63 non-teaching staffs.

IT Palakkad currently offers four-year Bachelor of Technology (B.Tech) and two years MS programmes in 8 different engineering disciplines including&nbsp;Computer Science, Electrical, Mechanical, Civil among others.

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IIT Palakkad

Water Science and Technology

The study investigates the performance of Cu2+ as dissolved cathodic electron-shuttle mediator (dcESM) for simultaneous Cr6+ reduction and electricity generation in a microbial fuel cell (MFC) at pH 2 and 4 conditions. The dcESM behavior of Cu2+ on carbon cloth (CC) catalyzes the reduction of Cr6+ into Cr3+ at pH 2 by undergoing redox reactions. However, at pH 4, a simultaneous reduction of Cu2+ and Cr6+ was observed. Cyclic voltammetry studies were performed at pH 2 and 4 to probe the dcESM behavior of Cu2+ for Cr6+ reduction on CC electrode. Also, at pH 2, increasing the concentration of Cu2+ from 50 to 500 mg L- 1 favors the Cr6+ reduction by reducing the reaction time from 108 to 48 h and improving the current production from 3.9 to 6.2 mA m- 2, respectively. Nevertheless, at pH 4, the efficacy of Cr6+ reduction and electricity generation from MFC is decreased from 63 to 18% and 4.4 to 1.1 mA m- 2, respectively, by increasing the Cu2+ concentration from 50 to 500 mg L- 1. Furthermore, the performance of dcESM behavior of Cu2+ was explored on carbon felt (CF) and platinum (Pt) electrodes, and compare the results with CC. In MFC, at pH 2, with an initial concentration of 100 mg L- 1, the reduction of Cr6+ in 60 h is 9.6 mg L- 1 for CC, 0.2 mg L- 1 for CF, and 51.3 mg L- 1 for Pt cathodes. The reduction of Cr6+ (initial concentration of 100 mg L- 1) at pH 4 in 120 h is 44.7 mg L- 1 for CC, 32.1 mg L- 1 for CF, and 70.9 mg L- 1 for Pt cathodes. Maximum power densities of 1659, 1509, and 1284 mW m- 2 were achieved when CF, CC, and Pt, respectively were employed as cathodes in the MFC. © 2020 The Author(s).

Journal	Water Science and Technology
Publisher	IWA Publishing
ISSN	02731223