Remediation of saline-sodic soil by plant microbial desalination cell.

Abstract Saline-sodic soil is widely distributed around the world and has induced severe impacts on ecosystems and agriculture. Plant microbial desalination cell (PMDC) and soil microbial desalination cell (SMDC) were constructed to migrate excessive salt in the soil in this study. Compared with SMDC, PMDCs generated higher voltage ranging from 150 mV to 410 mV (500Ω) and the maximum power density reached 34 mW/m2. Higher desalinization efficiency was obtained by PMDCs, the soil conductivity reduced from initial 2.4 mS/cm to 0.4 ± 0.1 mS/cm and pH decreased from initial 10.4 to 8.2 ± 0.1. Soils desalination in PMDCs was achieved through multiple pathways, including ion migration in PMDCs driven by electrokinetic process, plant absorption and bioremediation by plant roots and anode microorganism activity. Geobacter was the dominant electrogenic bacteria at the PMDC anode. The electrochemical and desalinating performance of PMDCs was enhanced by plants and provided a new method for remediation of saline-sodic soil.