{
    "title": "Cellulose-Polymer Water Filter",
    "inventor_name": "Monica EK",
    "publication_year": 2017,
    "device_name": "Cellulose-Polymer Water Filter",
    "goal": "Provide a portable, electricity-free water purification system that removes bacteria and viruses from raw water.",
    "problem_addressed": "Lack of clean drinking water in emergency or infrastructure-poor settings and need for non-toxic antibacterial filtration.",
    "concept_summary": "A filter made from wood-derived cellulose fibres coated with a positively-charged polymer (polyvinylamine) that electrostatically attracts and binds negatively-charged bacteria and viruses. Water passes by gravity; bacteria are trapped on the filter surface and the used filter can be safely burned, leaving no toxic residues.",
    "detailed_description": null,
    "category": "Materials Science & Ceramics",
    "principles": [
        "Electrostatic attraction between positively-charged polymer and negatively-charged microorganisms",
        "Contact-active antibacterial killing",
        "Gravity-driven filtration"
    ],
    "scientific_domains": [
        "Materials Science",
        "Chemical Engineering",
        "Environmental Engineering",
        "Microbiology"
    ],
    "mechanisms_of_action": [
        "Surface charge reversal to bind bacteria",
        "Adsorption of microorganisms onto polymer-coated cellulose",
        "Contact-based cell membrane disruption"
    ],
    "materials": [
        "Cellulose (wood fibres, nanofibrils)",
        "Polyvinylamine (PVAm)",
        "Polyacrylic acid (PAA) - optional multilayer component"
    ],
    "energy_sources": [
        "Gravity (no external power required)"
    ],
    "inputs": [
        "Raw water containing bacteria/viruses",
        "Filter material (cellulose-polymer composite)"
    ],
    "outputs": [
        "Purified water",
        "Bacteria-laden filter (can be burned after use)",
        "No leached toxic chemicals"
    ],
    "claimed_performance": "Traps >99.9% of bacteria; no toxic leaching; filter can be safely burned after use.",
    "experimental_evidence": "Laboratory tests showed >99.9% bacterial adhesion to the polymer-coated cellulose surface; the material was demonstrated in a gravity-driven prototype filter.",
    "replication_status": "Prototype tested in laboratory; no commercial scaling reported.",
    "keywords": [
        "cellulose",
        "polyvinylamine",
        "antibacterial filter",
        "gravity filtration",
        "portable water purification",
        "electrostatic adsorption"
    ],
    "related_technologies": [
        "Antibacterial fibres",
        "Cellulose aerogels",
        "Layer-by-layer polymer coatings"
    ],
    "controversy_level": "low",
    "confidence_score": 0.85,
    "practicability_score": 0.75,
    "fringe_score": 0.2,
    "evidence_strength": 0.7,
    "risk_score": 0.2,
    "trl_estimate": 5,
    "source_urls": [
        "https://phys.org/news/2017-03-filter-wood-portable-eco-friendly-purification.html",
        "https://phys.org/news/2013-02-eco-safe-antibacterial-fibre.html",
        "http://kth.diva-portal.org/smash/record.jsf?pid=diva2%3A1071204&dswid=2069",
        "http://kth.diva-portal.org/smash/record.jsf?pid=diva2%3A917790&dswid=195"
    ],
    "organizations": [
        "KTH Royal Institute of Technology"
    ],
    "applications": [
        "Emergency water treatment",
        "Portable water purification kits",
        "Antibacterial bandages and medical textiles",
        "Food packaging"
    ],
    "limitations": [
        "Filter must be replaced or burned after a limited usage period",
        "Effectiveness against viruses not fully quantified",
        "Scaling to large-volume water treatment not demonstrated"
    ],
    "open_questions": [
        "How many filtration cycles can the material sustain before performance degrades?",
        "What is the long-term stability of the polymer coating under field conditions?",
        "Can the technology be adapted for continuous flow systems?"
    ],
    "red_flags": [],
    "evidence_quotes": [
        "The material, which combines wood cellulose with a positively-charged polymer, can trap bacteria by attracting and binding the bacteria to the material surface.",
        "The results show that >99.9% of the bacteria adhered to the surface of the aerogels.",
        "Our aim is that we can provide the filter for a portable system that doesn't need electricity - just gravity - to run raw water through it.",
        "After it is used, the filter can be burned.",
        "The bacteria trapping material does not leach any toxic chemicals into the water, as many other on-site purification methods do."
    ]
}