Aeration-driven piezocatalytic fuel cell with single-atom Fe-doped MoS2 anode for efficient sulfide removal

An aeration-driven piezocatalytic fuel cell (PzFC) was tested for sulfide removal. • Single-atom Fe-doped MoS 2 piezoanode enhanced the oxidation of sulfide. • The PzFC achieved sulfide removal of 2.53 kg/(m 3 ·d) with 83% selectivity of S 0 /S n 2- . Sulfide (S 2- , HS - , and H 2 S) can be directly oxidized by air, but the reaction kinetics are sluggish, and the resulting sulfate product is stable but of low value. To accelerate sulfide oxidation to recoverable value-added products, we constructed an aeration-driven piezocatalytic fuel cell (PzFC) with single-atom Fe 1 @MoS 2 catalysts, in which mechanical strain was induced by continuous air bubbling. Herein, the sulfide was oxidized and selectively converted to low-toxicity products: about 83% elemental sulfur/polysulfides (S 0 /S n 2- ), with minor soluble sulfate (SO 4 2- ) and thiosulfate (S 2 O 3 2- ). S 0 /S n 2- can be used to enhance biological denitrification in wastewater treatment. Notably, the PzFC achieved 93% sulfide removal (initial concentration: 170 mg/L) within 90 min and exhibited stability over six consecutive cycles. Key operational parameters (temperature, pH, initial sulfide concentration, and aeration rate) were systematically evaluated, achieving a maximum desulfurization capacity of 20.68 g/(m 2 ·h) (i.e., 4.96 kg/(m 3 ·d) at an initial concentration of 470 mg/L). Furthermore, the influences of self-bias and single-atom Fe loading on PzFC performance were systematically clarified, and the underlying catalytic mechanism was proposed. This work establishes a low-carbon, efficient strategy for wastewater desulfurization by integrating single-atom piezocatalysts Fe 1 @MoS 2 and PzFC. Download: Download high-res image (240KB) Download: Download full-size image