High-efficient solar steam generation assisted removal of radioactive iodine ions from water by carbonized conjugated microporous polymer-based photothermal conversion materials

Abstract

Solar steam generation has recently received much attention as a new green and environmentally responsible technology for seawater desalination or wastewater treatment. Hence, a novel and efficient strategy is proposed for removal of radioactive iodine ions from wastewater by SSG method using carbonized conjugated microporous polymers (CCMPs) as photothermal conversion materials. Because of the porous structure and strong light absorption of the CCMPs-based interfacial evaporator and the excellent thermal insulation of the expandable polyethylene sponge, CCMP-1 evaporator achieved a high photothermal conversion efficiency (95.39%) and stable water evaporation rate (1.5879 kg m−2 h−1) at one solar irradiation. In addition, the using of green solar energy as evaporation driving force could accelerate the transferring of iodine ions containing water through CMPs derived solar evaporator, which in turn improved the mass transfer. More importantly, the results of interfacial evaporation experiments on aqueous solutions containing iodine ions (0.2 mmol L−1) revealed that the concentration of iodine ions in the collected condensate was only 0.0027 mmol L−1, which decreased nearly three orders of magnitudes of initial concentration. Also, the iodine ions in water were almost completely enriched by the interfacial evaporator CCMP-1. In view of the fact of big challenge of removal of radioactive iodine ions from wastewater, remaining in current technologies, the findings of this study might provide a simple and efficient solution for treatment of radioactive pollutions contained in wastewater using green solar energy as deriving force via the SSG method.