Control of exposure to hexavalent chromium concentration in shielded metal arc welding fumes by nano-coating of electrodes

2020

Sustain Environ Res

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.

Section: Resultsmentioning

confidence: 98%

“…In recent years, hexavalent chromium (Cr 6+ ) is exceedingly prevalent in various industrial effluents, and is often discharged from metallurgy, electroplating, leather tanning, and textile industries [1]. Cr 6+ is a well-known mutagen, teratogen, and carcinogen [2].…”

Section: Introductionmentioning

confidence: 99%

The performance of Cu2+ as dissolved cathodic electron-shuttle mediator for Cr6+ reduction in the microbial fuel cell

2020

Sustain Environ Res

“…However, simultaneous reductions of Cu 2+ and Cr 6+ were occurred owing to the high cathodic potential as presented in Eqs. (1) and (5), respectively. The pH was observed to increase from 4 to 5.54 and the color of the effluent was changed from orange-yellow to pale yellow.…”

Section: The Dcesm Behavior Of Cu 2+ For Cr 6+ Reductionmentioning

confidence: 99%

The performance of Cu2+ as dissolved cathodic electron-shuttle mediator for Cr6+ reduction in the microbial fuel cell

2020

Preprint

The study investigates the performance of Cu 2+ as dissolved cathodic electron-shuttle mediator (dcESM) for simultaneous Cr 6+ reduction and electricity generation in a microbial fuel cell (MFC) at pH 2 and 4 conditions. The dcESM behavior of Cu 2+ on carbon cloth (CC) catalyzes the reduction of Cr 6+ into Cr 3+ at pH 2 by undergoing redox reactions. However, at pH 4, a simultaneous reduction of Cu 2+ and Cr 6+ was observed. Cyclic voltammetry (CV) studies were performed at pH 2 and 4 to probe the dcESM behavior of Cu 2+ for Cr 6+ reduction on CC electrode. Also, at pH 2, increasing the concentration of Cu 2+ from 50 mg L -1 to 500 mg L -1 favors the Cr 6+ reduction by reducing the reaction time from 108 h to 48 h and improving the current production from 3.94 mA m -2 to 6.24 mA m -2 , respectively. Nevertheless, at pH 4, the efficacy of Cr 6+ reduction and electricity generation from MFC is decreased from 62.91% to 18.21% and 4.42 mA m -2 to 1.10 mA m -2 , respectively, by increasing the Cu 2+ concentration from 50 mg L -1 to 500 mg L -1 . Furthermore, the performance of dcESM behavior of Cu 2+ 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 Cr 6+ in 60 h is 9.63 mg L -1 for CC, 0.17 mg L -1 for CF, and 51.32 mg L -1 for Pt cathodes. The reduction of Cr 6+ (initial concentration of 100 mg L -1 ) at pH 4 in 120 h is 44.72 mg L -1 for CC, 32.13 mg L -1 for CF, and 70.85 mg L -1 for Pt cathodes. Maximum power densities of 1659 mW m -2 , 1509 mW/m -2 , and 1284 mW/m -2 were achieved when CF, CC, and Pt, respectively were employed as cathodes in the MFC.

“…In recent years, hexavalent chromium (Cr 6+ ) is exceedingly prevalent in various industrial effluents, and are often discharged from metallurgy, electroplating, leather tanning, and textile industries [1]. Cr 6+ is a well-known mutagen, teratogen, and carcinogen [2].…”

Section: Introductionmentioning

confidence: 99%

The performance of Cu2+ as dissolved cathodic electron-shuttle mediator for Cr6+ reduction in the microbial fuel cell

2020

Preprint

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 (CV) 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 mg L− 1 to 500 mg L− 1 favors the Cr6+ reduction by reducing the reaction time from 108 h to 48 h and improving the current production from 3.94 mA m− 2 to 6.24 mA m− 2, respectively. Nevertheless, at pH 4, the efficacy of Cr6+ reduction and electricity generation from MFC is decreased from 62.91–18.21% and 4.42 mA m− 2 to 1.10 mA m− 2, respectively, by increasing the Cu2+ concentration from 50 mg L− 1 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 9.63 mg L− 1 for CC, 0.17 mg L− 1 for CF, and 51.32 mg L− 1 for Pt cathodes. The reduction of Cr6+ (initial concentration of 100 mg L− 1) at pH 4 in 120 h is 44.72 mg L− 1 for CC, 32.13 mg L− 1 for CF, and 70.85 mg L− 1 for Pt cathodes. Maximum power densities of 1659 mW m− 2, 1509 mW/m− 2, and 1284 mW/m− 2 were achieved when CF, CC, and Pt, respectively were employed as cathodes in the MFC.