Effective removal of mercury (Hg) contamination from wastewater is of great</p><p>significance due to the extremely high toxicity of Hg, especially MeHg. Reducing of</p><p>Hg(II) to Hg(0) by the reducibility of iron minerals in constructed wetlands (CWs) is an</p><p>effective strategy to avoid the formation of MeHg and enhance Hg removal. While the</p><p>surface passivation of iron minerals limited its application.