Materials for moisture and water harvesting from air

Overview

This solution introduces a composite material designed to harvest moisture and water directly from ambient air, even at moderate humidity levels. The material leverages a hydrophilic porous structure containing a low water activity substance that attracts moisture, induces microcondensation, and rapidly wicks away collected droplets before water can saturate the pores. Laboratory demonstrations have shown that this approach enables sustained water harvesting at room temperature (~25°C) and 65% relative humidity, conditions well above the traditional dew point threshold.

The technology addresses growing demand for decentralized, energy-efficient water sources in arid regions, emergency response scenarios, and off-grid applications where conventional water infrastructure is unavailable or impractical.

Technical specifications

Core material design:

• A hydrophilic matrix containing micropores provides the structural framework
• Low water activity materials (such as hygroscopic salts) are confined within the micropores to drive moisture attraction
• The composite induces microcondensation and droplet formation at humidity levels below saturation
• Rapid wicking prevents pore flooding, enabling continuous operation

Key features:

• Operates at ambient temperature without refrigeration or condensation cycles
• Harvests water from air at 60–65% relative humidity, conditions common in many indoor and outdoor environments
• Material geometry is tailored to promote droplet drainage and collection
• Compatible with simple mesh-based deployment for passive airflow operation

Demonstrated performance:

• A 0.015 m² mesh coated with 0.5 g of confined hygroscopic silver nitrate in superhydrophilic titania produced measurable water collection
• Collected water has been analyzed for pH and basic water quality parameters
• Setup uses a fan-driven air circulation system with a collection dish beneath the mesh

Technology readiness level

The technology has been validated at small laboratory scale under controlled indoor conditions. Current results demonstrate proof of concept for the harvesting mechanism and material composition. Further validation is needed through larger scale experiments, testing under varied air conditions (different temperatures and humidity ranges), and extended-duration trials to assess long-term material stability and water yield. The material is not yet ready for commercial deployment but represents a promising foundation for scale-up and field testing.