Interfacial solar evaporation driven lead removal from a contaminated soil

Abstract

Interfacial solar steam generation is a green and sustainable technology which has been intensively studied in the fields of seawater desalination and wastewater purification for clean water production. Here, this technology is further developed for soil remediation. A new photothermal evaporator is designed to accelerate the extraction of lead (Pb) from soil solution, thereby successfully rapidly remediating a Pb contaminated soil. Within 2 weeks, this solar-driven evaporative remediation (SDER) simultaneously decreases the bioavailable Pb fraction by 38.4% (from 359 to 221 mg kg−1) with no excessive nutrient loss nor secondary pollution. Post remediation plant assay indicates that the treated soil is significantly less phytotoxic, with shoot/root Pb contents decreasing by 50%. Since SDER involves no external energy input; other than solar irradiation; ongoing operating costs are low leading to significant potential for sustainable practical applications. Overall, this study demonstrates for the first time that interfacial solar evaporation can be successfully applied to soil remediation. (Figure presented.).