Hybrid water vapor sorbent design with pollution shielding properties : extracting clean water from polluted bulk water sources

Abstract

The shortage and contamination of local water resources have long been a challenge especially for off-grid communities without centralized water supply. The emerging solar photothermal distillation lacks the capability of handling polluted source water with a wide range of common environmental pollutants. Based on water vapor harvesting, this work reports a Simple Water Extraction Apparatus with Pollutant Shielding (SWEAPS) design which is able to efficiently produce clean water from various polluted liquid water sources and the atmosphere. SWEAPS is fabricated by encapsulating a water vapor sorbent by an omniphobic fabric. The omniphobicity of the encapsulation fabric endows SWEAPS with self-floating capability and the ability to screen out the contaminants in the source water. The self-floating properties of SWEAPS allow it to harvest clean water vapor right above the source-water-air interface where the relative humidity is close to 100%, leading to its much higher water harvesting capacity than that of the same material harvesting water vapor from the ambient atmosphere. Due to the chemical and physical stability, anti-bacterial, pollution and corrosion shielding effects of SWEAPS, it is demonstrated to produce clean water meeting the WHO drinking water standard from various polluted water resources, such as seawater, contaminated water, and amazingly untreated real domestic wastewater. SWEAPS has the potential to produce clean water for point of consumption at a decentralized scale and thus to improve the quality of life for those who need water most.