A photothermal hydrogel-fabric architected with polyvinyl alcohol decorated polypyrrole nanoparticles for efficient brine distillation

• Published in: Applied surface science 2024-07, Vol.662, p.160110, Article 160110
• Main Authors: Han, Li, Yang, Man, Zhou, Haifeng, Hong, Chenxiao, Li, Jingye, Ma, Hongjuan, Zhang, Bowu
• Format: Article
• Language: English
• Subjects: Acetalization; Desalination; Photothermal hydrogel-fabric; Polypyrrole; Solar evaporator
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2024.160110

[Display omitted] •PVA decorated PPy nanoparticles is prepared and used to architect photothermal hydrogel-fabric with good durability.•Photothermal hydrogel-fabric breaks through the thermodynamic upper limit of 2D evaporator.•A 3D cylindric evaporator achieves stable evaporation in long time for high-salt water.•3.43 kg m−2 of fresh water generated in 4 h outdoor evaporation even in the winter. Herein, water-dispersible polypyrrole (PPy)-based nanoparticles were synthesised from polyvinyl alcohol (PVA) via acetalization with pyrrole-2-carboxaldehyde and in situ graft redox polymerization of pyrrole. The PVA decorated PPy nanoparticles were facilely anchored onto cotton fabric via drop-casting and borate-crosslinking to form a robust photothermal hydrogel-fabric (PHF). The new PHF material achieves strong sunlight absorption capacity (>92 %) and high evaporation rate (1.62 kg m–2 h−1) of pure water on 2D platform under 1-sun irradiation. Further, a self-floating 3D evaporator (3D-PHF) was constructed by wrapping the PHF material on an expanded polyethylene cylinder, which unexpectedly exhibits high evaporation rate from pure water (2.03 kg m–2 h−1) and brines with different concentrations (1.95 kg m–2 h−1 for 3.5-wt% and 1.85 kg m–2 h−1 for 10-wt%). Cumulative 100 h long-time evaporation confirms the 3D-PHF evaporator even maintained a stable evaporation efficacy to 20-wt% brine (1.55 kg m–2 h−1) due to its self-renewal features triggered by the gravity of deposited salt on upper surface. This study paves a simple pathway to architect novel photothermal material with good solar evaporation efficacy, which contributes to the applications of solar evaporation to saline water treatment.