A sodium hyposulfite fuel cell for efficient Cr(VI) removal

Area of Science:

• Environmental Chemistry
• Electrochemistry
• Wastewater Treatment

Background:

• Hexavalent chromium (Cr(VI)) poses significant environmental and health risks.
• Conventional Cr(VI) remediation methods can be costly and generate secondary pollutants.
• Simultaneous pollution treatment and energy generation is a desirable goal.

Purpose of the Study:

• To develop an efficient and eco-friendly method for Cr(VI) reduction.
• To investigate the feasibility of generating electricity during Cr(VI) remediation.
• To evaluate the performance and reusability of a novel dual-chamber non-biological fuel cell (D-nBFC) system.

Main Methods:

• Utilized a dual-chamber non-biological fuel cell (D-nBFC) with graphite felt (GF) electrodes.
• Employed sodium hyposulfite (Na2S2O3) for electro-oxidation at the anode.
• Achieved electro-reduction of Cr(VI) to Cr(III) at the GF/CCP cathode in acidic solution, with an agar salt bridge completing the circuit.

Main Results:

• Achieved a high Cr(VI) removal efficiency of 97.0% within 4 hours.
• Generated electricity with a maximum current of 110 μA and a maximum power density of 13.4 mW m⁻².
• Demonstrated excellent reusability over five cycles with a low relative standard deviation of 3.4%.

Conclusions:

• The D-nBFC system offers a promising, sustainable approach for simultaneous Cr(VI) remediation and electricity generation.
• The system's high efficiency, reusability, and eco-friendly nature highlight its potential for treating heavy metal pollution.
• This technology shows potential for broader applications in remediating other heavy metal contaminants.