A Fenton-integrated siphon evaporator for efficient removal of volatile fecal odors during interfacial steam generation

Solar interfacial evaporation (SIE) is a prospective technology to overcome global freshwater shortages, but most current solar interfacial evaporators fail to treat fecal wastewater due to the presence of unpleasant volatile odors. Herein, a functional solar interfacial evaporator was developed to efficiently remove volatile fecal odors by integrating solar interfacial evaporation with Fenton oxidation in a continuous capillary-driven siphon mode. The evaporation interface was prepared by sequentially loading β-FeOOH and polydopamine-modified reduced graphene oxide (PDA-RGO) on a hydrophilic nonwoven substrate as the Fenton catalyst and photothermal material for simultaneous removal of pollutants during evaporation. Significantly, the prepared evaporator achieved a 100 % removal rate for volatile fecal odors and good removal efficiency of other organic pollutants in condensate and percolate, which was 7.29 times than that of the sole solar interfacial evaporator (13.7 %). Meanwhile, the unique capillary-driven siphon mode allowed continuous production of clean condensate and percolate without volatile fecal odors maintaining excellent stability in fifteen cycles. This development is considered to provide a feasible strategy for purifying wastewater to supply potable water without volatile fecal odors by using solar interfacial evaporation.