Implementation of a Sulfide-Air Fuel Cell Coupled to a Sulfate-Reducing Biocathode for Elemental Sulfur Recovery

Area of Science:

• Environmental Biotechnology
• Electrochemistry
• Wastewater Treatment

Background:

• Bio-electrochemical systems (BES) offer a versatile platform for wastewater treatment and valuable product recovery.
• Sulfate-rich wastewaters often lack electron donors, posing treatment challenges.
• Elemental sulfur (S⁰) recovery from sulfate is a potential solution for such wastewaters.

Purpose of the Study:

• To propose and evaluate a novel BES configuration for simultaneous sulfate reduction and elemental sulfur recovery.
• To assess the efficiency of elemental sulfur production and sulfate removal.
• To compare the energy consumption of the proposed system with conventional methods.

Main Methods:

• A novel BES configuration was developed, integrating bio-electrochemical sulfate reduction in a biocathode with a sulfide-air fuel cell.
• The system's performance was evaluated based on elemental sulfur production rates and sulfate removal efficiency.
• Energy consumption was quantified and compared to conventional electrochemical sulfur recovery systems.

Main Results:

• The proposed BES achieved high elemental sulfur production rates, reaching up to 386 mg S⁰-S L^-1 d^-1.
• 65% of the removed sulfate was successfully recovered as elemental sulfur (S⁰).
• The system demonstrated a 12% lower energy consumption per kg of S⁰ produced compared to conventional methods.

Conclusions:

• The novel BES configuration is effective for treating sulfate-rich wastewater and recovering elemental sulfur.
• This approach offers a more energy-efficient method for elemental sulfur recovery.
• The study highlights the potential of integrated BES for sustainable wastewater management and resource recovery.