Polypyrrole‐Reinforced N,S‐Doping Graphene Foam for Efficient Solar Purification of Wastewater

Abstract

Solar vapor generation is a sustainable and cost‐effective approach to addressing the issue of water shortage. However, the challenges of solar steam generation still exist for achieving a high evaporation efficiency combined with long‐term stability in the wastewater containing heavy metal ions and wide degrees of acidity and alkalinity (pH = 1–14). Herein, polypyrrole (PPy) loading on the N,S‐doped graphene oxide (N,S‐GO) foam is used for high‐efficiency solar evaporation of treating wastewater. With the advantages of excellent broadband solar absorption ( >97%), extremely low emissivity (0.70), and outstanding hydrophilicity, the N,S‐GO/PPy foam achieves a high evaporation efficiency of 90.5% under 1 sun illumination. More notably, the N,S‐GO/PPy foam has strong adsorption of heavy metal ions (Fe3+, Cu2+, and Cr6+) for treating wastewater synchronously evaporates at higher efficiencies of 94.7–98.4%. Interestingly, the high‐toxicity Cr6+ can be reduced to low‐toxicity Cr3+ effectively by the synergistic effect of N,S‐GO and PPy. In addition, the N,S‐GO foam shows a better long‐term resistance of acidity and alkalinity for 45 days. A new insight is offered into high‐efficiency solar evaporation for treating wastewater and water purification.