Goal
Provide affordable, safe drinking water by removing pathogens and toxic chemicals.
Problem
Contaminated drinking water containing bacteria, viruses, heavy metals (lead, arsenic), pesticides and other toxins.
Concept Summary
A low-cost water filter made from an aluminium-based composite that embeds silver nanoparticles and other nanostructured adsorbents (iron oxyhydroxide, manganese oxide, chitosan). As water passes, silver nanoparticles oxidise and release Ag^+ ions that kill microbes, while the other nanomaterials adsorb heavy metals and chemical contaminants. The filter works without electricity and can treat hundreds of litres of water before regeneration.
Detailed Description
The filter consists of a sand-like granular composite in which silver nanoparticles are isolated within a chitosan-gel matrix, preventing agglomeration and controlling ion release. Iron oxyhydroxide particles scavenge arsenic, manganese oxide adsorbs lead, and other nanomaterials target additional contaminants. The composite is fabricated at room temperature in water, requires no external power, and can be regenerated by brief hot-water flushing when ion release diminishes. Field trials in West Bengal, India, have demonstrated that a 120 g filter costing ~US$2 can supply safe water for a family of five for one year (~=1500 L filtered per 50 g of composite).
Principles
- Antimicrobial silver ion release
- Adsorption of heavy metals
- Nanocomposite filtration
- Controlled ion diffusion through polymer matrix
Scientific Domains
Materials
- Silver nanoparticles
- Aluminium composite matrix
- Iron oxyhydroxide nanoparticles
- Manganese oxide nanoparticles
- Chitosan
Mechanisms of Action
- Silver ions disrupt bacterial and viral cell membranes
- Iron oxyhydroxide chemically binds arsenic ions
- Manganese oxide chemically binds lead ions
- Polymer matrix limits nanoparticle leaching and controls ion release
Applications
- Drinking water purification in low-income and remote communities
Claimed Performance
A 120 g filter costing $2 provides safe drinking water for a family of five for one year (~=1500 L filtered per 50 g of composite without reactivation).
Experimental Evidence
Laboratory test: 50 g composite filtered 1500 L of water without reactivation. Field trials underway in West Bengal, India; pilot phase completed; commercial release planned.
Replication Status
Field trials ongoing; pilot phase completed; technology moving toward commercial scale.
Limitations
- Small amount of silver nanoparticle leaching (though below health thresholds)
- Performance declines after prolonged use; requires periodic hot-water regeneration
