Graphene Array-Based Anti-fouling Solar Vapour Gap Membrane Distillation with High Energy Efficiency

• Published in: Nano-micro letters Vol. 11; no. 1; pp. 1 - 14
• Main Authors: Gong, Biyao, Yang, Huachao, Wu, Shenghao, Xiong, Guoping, Yan, Jianhua, Cen, Kefa, Bo, Zheng, Ostrikov, Kostya
• Format: Journal Article
• Language: English
• Published: Singapore Springer Singapore 01.12.2019; Springer Nature B.V; SpringerOpen
• Subjects: Antifouling; Arrays; Collection; Contaminants; Desalination; Distillation; Distilled water; Energy conversion efficiency; Energy efficiency; Engineering; Fouling; Graphene; Heating; Membrane separation; Membranes; Nanochannels; Nanoscale Science and Technology; Nanotechnology; Nanotechnology and Microengineering; Photothermal conversion; Plasma-made nanostructures; Power efficiency; Seawater; Separation; Solar energy; Transport; Vapors; Water purification; Water yield; Water purification; Plasma-made nanostructures; Photothermal conversion; Solar energy
• ISSN: 2311-6706; 2150-5551; 2150-5551
• DOI: 10.1007/s40820-019-0281-1

Highlights New concept of solar vapour gap membrane distillation (SVGMD) is based on synergizing of nanochannel-guided water transport, localized heating, and membrane separation from feed solution. First-time introduction of the gap enables long-term stability and non-fouling membrane. SVGMD exhibits a solar-water energy efficiency higher than state-of-the-art solar vapour systems. Photothermal membrane distillation (MD) is a promising technology for desalination and water purification. However, solar-thermal conversion suffers from low energy efficiency (a typical solar-water efficiency of ~ 50%), while complex modifications are needed to reduce membrane fouling. Here, we demonstrate a new concept of solar vapour gap membrane distillation (SVGMD) synergistically combining self-guided water transport, localized heating, and separation of membrane from feed solution. A free-standing, multifunctional light absorber based on graphene array is custom-designed to locally heat the thin water layer transporting through graphene nanochannels. The as-generated vapour passes through a gap and condenses, while salt/contaminants are rejected before reaching the membrane. The high solar-water efficiency (73.4% at 1 sun), clean water collection ratio (82.3%), excellent anti-fouling performance, and stable permeate flux in continuous operation over 72 h are simultaneously achieved. Meanwhile, SVGMD inherits the advantage of MD in microorganism removal and water collection, enabling the solar-water efficiency 3.5 times higher compared to state-of-the-art solar vapour systems. A scaled system to treat oil/seawater mixtures under natural sunlight is developed with a purified water yield of 92.8 kg m −2  day −1 . Our results can be applied for diverse mixed-phase feeds, leading to the next-generation solar-driven MD technology.