Superwetting B4C bilayer foam for high cost-performance solar water purification

• Published in: Materials today energy Vol. 18; p. 100498
• Main Authors: Zhao, Q., Huang, Z., Tian, S., Cui, X., Wan, Y., Li, X., Xiao, Y., Li, S., Lee, C.-S.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.12.2020
• Subjects: Absorber; Boron carbide; Hierarchical network; Seawater desalination; Solar steam; Wastewater purification; Wastewater purification; Solar steam; Hierarchical network; Seawater desalination; Boron carbide; Absorber
• ISSN: 2468-6069; 2468-6069
• DOI: 10.1016/j.mtener.2020.100498

Solar water evaporation holds great promising for future seawater desalination and wastewater purification via solar energy harvesting and efficient steam generation. While many performance advances have been achieved, up to now the low cost-performance remains a serious hindrance to practical applications. To overcome the limitations, herein we developed a boron carbide bilayer foam (BCBF) based solar evaporator to achieve a record high cost-effectiveness on seawater desalination and wastewater purification. Via integrating full-solar absorbing boron carbide into a porous PVA framework, the BCBF achieves a good hydrophilic wettability, heat-shielding and solar-thermal conversion to offer a high evaporation rate as high as 2.8 kg/m2/h with 93% solar evaporation efficiency under 1 sunlight radiation. Prepared in one step using commercially available low-cost raw materials, the BCBF evaporator is demonstrated to possess an ultra-high cost-effectiveness of 778 g/h/$, far beyond previously reported solar evaporation systems. Practical freshwater production from seawater and multiple wastewaters, with high stability under extreme conditions were also demonstrated. This work suggests a good performance and highly cost-effective solar evaporator for practical water purification. A boron carbide bilayer foam (BCBF) are explored for high cost-performance seawater desalination and wastewater purification. Low-cost commercial B4C powder is embedded into a porous polymer foam in one simple step to prepare boron carbide bilayer foam (BCBF) with good hydrophilic wettability, heat-shielding, and solar-thermal conversion, with a low-cost of 3.6 $/m2. Notably, under 1 sunlight illumination, the BCBF offers a high evaporation rate of 2.8 kg/m2/h with 93% solar evaporation efficiency. To best our knowledge, this BCBF evaporator is demonstrated to possess an ultra-high cost-effectiveness of 778 g/h/$, superior to recently reported solar evaporation systems. This work suggests an excellent and cost-effective solar evaporator tool for practical water purification. [Display omitted] •The boron carbide bilayer foam (BCBF) offers a high evaporation rate of 2.8 kg m-2 h-1 with 93% solar evaporation efficiency.•The composite foam evaporator possesses an ultra-high cost-effectiveness of 778 g h-1 $-1.•BCBF can maintain its function even under extreme conditions (e.g. pH∼1, pH∼14, high salinity with saturated salt concentration).