Decreasing sulfide in sediment and promoting plant growth by plant–sediment microbial fuel cells with emerged plants

Four plant–sediment microbial fuel cells (plant-SMFCs) with four plant species, Oryza sativa, Acorus calamus, Spathiphyllum petite and Chamaedorea elegans, were built to investigate sulfide concentrations, pH and oxidation–reduction potential (ORP) in the sediment as well as plant growth. Sulfide concentrations at 1 and 2 cm depth of sediment in plant-SMFCs and their control reactors were 1.66 ± 0.30, 9.29 ± 3.46, 2.38 ± 0.10 and 24.20 ± 1.02 μmol g−1, respectively. The ORP in water and sediment of 1 and 2 cm depth in plant-SMFCs was 106.0 ± 7.7, − 142 ± 30 and − 209 ± 9 mV, respectively. The ORP in the three control reactors was 119.0 ± 11.5, − 209 ± 9 and − 386 ± 2 mV, respectively. Harvest of O. sativa, A. calamus, Spathiphyllum petite and C. elegans was 0.218 ± 0.009, 0.136 ± 0.007, 0.127 ± 0.007 and 0.340 ± 0.007 gDW g−1GW in the plant-SMFCs, while that of their control reactors was 0.179 ± 0.011, 0.127 ± 0.008, 0.102 ± 0.007 and 0.318 ± 0.006 gDW g−1GW, respectively. The results showed that sulfide concentrations decreased in sediments of plant-SMFCs, while the ORPs in both the overlying water and sediments increased. Moreover, plant growth due to operating plant-SMFCs was promoted. Running plant-SMFCs abates the toxicity of sulfide to the emerged plants as well as decreases the sulfide emission in water–plant–sediment systems.