Journal of Electroanalytical Chemistry, Vol.764, 38-44, 2016
A urine/Cr(VI) fuel cell - Electrical power from processing heavy metal and human urine
This work shows a strategy of reducing Cr(VI) by human urine with self-generation electricity via a urine/Cr(VI) fuel cell (UCrFC), in which urine functions as fuel and Cr(VI) severs as oxidant. Fresh urine is electro-oxidized on carbon supported nano-Ni catalyst at anode and strong acidic Cr(VI) synthetic wastewater is electro-reduced at catalyst-free cathode. An ion selective separator, consisting of an anion exchange membrane and a cation exchange membrane, is introduced to improve the cell performance by hindering the crossover of dichromate and ammonium. Using 50 mg L-1 Cr(VI) in 0.25 M H2SO4 as catholyte, neat urine as anolyte, the maximum power density of UCrFC reached 3.4 W m(-2) with an open circuit voltage (OCV) of 1.3 V. More than 90% of Cr(VI) was reduced with coulombic efficiency of more than 98%, meanwhile total carbon and nitrogen in urine was also removed with efficiency about 78%. The effects of initial Cr(VI) and H2SO4 concentration were investigated. The specific capacity of UCrFC reached 4417 mAh per liter of human urine. (C) 2016 Elsevier B.V. All rights reserved.
Keywords:Electrochemical energy conversion;Wastewater treatment;Nitrogen removal;Hexavalent chromium;Ion exchange membrane