Efficient purification of methylene blue dye wastewater by integrated photocatalysis and photothermal evaporation

Abstract Herein, a novel NH 2 –MIL–53(Fe)/polypyrrole@cellulose fiber (NMF/PPy@CelF) composite was prepared based on cellulose fiber (CelF) by a double in-situ growth method, consisting of polypyrrole (PPy) and NH 2 –MIL–53(Fe) (NMF). The interfacial photocatalysis and photothermal properties of the obtained composite was systematically evaluated by treating 20 ml·L − 1 methylene blue (MB) sulotion under 1 kW·m − 2 illumination. The NMF/PPy@CelF composite showed good photocatalytic activity with a degradation rate of 76.90% of MB within 180 min. Moreover, the photothermal conversion efficiency of NMF/PPy@CelF reached 92.16%. The PPy layer not only improved the visible light absorption range and interfacial temperature of the composite, but also facilitated the separation of photoelectrons and holes, endowing the NMF/PPy@CelF composite with good photothermal and photocatalytic properties. Furthermore, superior stability of the NMF/PPy@CelF composite was observed in repeated cycles. In addition, the photocatalytic mechanism was proposed. This work combines the photothermal effect with solar-driven photocatalysis, simultaneously achieving complete degradation of dyes and the recovery of clean water from dye wastewater.