Hexavalent chromium reduction and energy recovery by using dual-chambered microbial fuel cell

Abstract

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).

Metals removal and recovery in bioelectrochemical systems: A review

“…Modification of the cathode with rutile (natural form of TiO 2 ) coating was suggested for improving Cr ( While 67.5% of V(V) had been reduced, most of the vanadium (V(IV) and residual V(V)) was present in the solution and requires an additional step such as hydroxide precipitation for removal and recovery. Cr(VI) present in the wastewater was bioelectrochemically reduced to Cr(III) in the presence of an organic electron donor in a dual-chambered MFC with simultaneous generation of electricity (Gangadharan and Nambi, 2015). The Cr(VI) as catholyte (100 mg/L) was completely removed within 48 h (initial pH 2.0) by precipitation on the cathode.…”

Feasibility Study of Disposed LCD Monitor and Carbon Cloth Electrodes for Synchronized Removal/Recovery of Cr6+ by Microbial Fuel Cells

“…PEM was pretreated with 30% H 2 O 2 , 0.5 M H 2 SO 4 , and deionized water for 1 h [5]. In MFC CC , non-wet proof plain carbon cloth (CC) (10.5 cm 2 ; Synergic India Pvt.…”

“…The sludge was washed several times with 0.85% of NaCl (w/v) solution, and the methanogenic activity was suppressed by applying heat shock treatment (100 °C, 2 h) [5]. The synthetic wastewater was prepared by mixing an appropriate quantity of macronutrients of NH 4 Cl, 125 mg/L; NaHCO 3 , 125 mg/L; MgSO 4 .7H 2 0, 51 mg/L; CaCl 2 .2H 2 O, 300 mg/L; FeSO 4 .7H 2 O, 6.25 mg/L, and 1.25 mL/L of micronutrients [11].…”

“…However, the usage of conventional catholyte is restricted for large scale application due to the toxicity of ferricyanide and large activation loss of oxygen. Recently, a few studies were successfully demonstrated Cr 6+ as catholyte in two-chambered MFC (t-MFC) due to its high reduction potential [5]. In fact, the standard half-cell potential (25 o C) of Cr 6+ displays moderately higher value than that of the half-cell potential of oxygen as shown in the Eqn.…”

Liquid crystal polaroid glass electrode from e-waste for synchronized removal/recovery of Cr +6 from wastewater by microbial fuel cell

“…The reduction of toxic Cr 6+ to non-toxic Cr 3+ in MFCs gains much more attention due to the lack of energy requirements, chemical consumption, generation of a large quantity of secondary pollutants and toxic waste sludge. However, most of the relevant studies performed were focused on the use of conventional expensive electrodes (Gangadharan and Nambi, 2015;Li et al, 2008). Hence, it is essential to find a novel, cheap electrode material for chromium reduction in MFCs.…”