{
    "title": "Graphene Oxide Desalination",
    "inventor_name": "Jijo Abraham et al.",
    "publication_year": 2017,
    "device_name": "Graphene oxide membrane (GO laminate membrane)",
    "goal": "To remove salts and other solutes from water by tunable ion sieving, enabling desalination and water purification.",
    "problem_addressed": "Conventional graphene oxide membranes swell in water, giving a pore size (~9 Angstrom) larger than hydrated ions, limiting ion sieving and desalination performance.",
    "concept_summary": "Physical confinement of graphene oxide laminates reduces interlayer spacing (d) from ~13.5 Angstrom to 6.4-9.8 Angstrom, creating size-exclusion nanocapillaries that reject hydrated ions while allowing water to pass with little resistance. The method yields membranes with ~97 % NaCl rejection and scalable fabrication.",
    "detailed_description": "The invention uses graphene oxide flakes stacked in parallel to form a laminate. By encasing the laminate with a rigid, porous encapsulating material (or by other confinement techniques) the swelling in water is limited, fixing the interlayer spacing. Membranes with spacings of 9.8 Angstrom down to 6.4 Angstrom are produced, providing a sieve smaller than the hydrated radii of common ions. Ion permeation follows thermally activated kinetics with energy barriers of 10-100 kJ mol^-^1, while water flux is only modestly reduced (factor < 2). A simple scalable production method is described, and laboratory tests show 97 % rejection of NaCl.",
    "principles": [
        "Size-exclusion (nanopore sieving) based on interlayer spacing",
        "Capillary-like pressure driving water flow in graphene nanocapillaries",
        "Thermally activated ion transport barriers"
    ],
    "scientific_domains": [
        "Materials Science",
        "Nanotechnology",
        "Chemical Engineering",
        "Environmental Engineering"
    ],
    "mechanisms_of_action": [
        "Physical confinement to control interlayer spacing",
        "Nanocapillary flow with low friction for water",
        "Electrostatic and steric exclusion of hydrated ions"
    ],
    "materials": [
        "Graphene oxide",
        "Encapsulating polymer (porous)",
        "Water"
    ],
    "energy_sources": [],
    "inputs": [
        "Feed water containing dissolved salts (e.g., NaCl)",
        "Physical confinement hardware"
    ],
    "outputs": [
        "Purified water",
        "Concentrated salt brine"
    ],
    "claimed_performance": "~=97 % NaCl rejection; water transport reduced by < 2x compared with unconstrained membranes; ion permeation barriers 10-100 kJ mol^-^1.",
    "experimental_evidence": "Laboratory membranes with d = 6.4-9.8 Angstrom demonstrated tunable ion sieving and 97 % NaCl rejection; ion permeation rates decreased exponentially with decreasing d while water flux changed little.",
    "replication_status": "Demonstrated at laboratory scale in the reported studies; no independent large-scale replication mentioned.",
    "keywords": [
        "graphene oxide",
        "desalination",
        "ion sieving",
        "nanocapillaries",
        "water purification",
        "membrane technology"
    ],
    "related_technologies": [
        "Reverse osmosis",
        "Forward osmosis",
        "Nanofiltration"
    ],
    "controversy_level": "low",
    "confidence_score": 0.9,
    "practicability_score": 0.8,
    "fringe_score": 0.2,
    "evidence_strength": 0.8,
    "risk_score": 0.1,
    "trl_estimate": 6,
    "source_urls": [
        "https://www.nature.com/articles/nnano.2017.21",
        "WO2018100384",
        "http://science.sciencemag.org/content/343/6172/752",
        "https://pubs.acs.org/doi/10.1021/acs.est.5b06032",
        "https://pubs.rsc.org/en/Content/ArticleLanding/2010/CS/B917103G#!divAbstract",
        "https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.201404054"
    ],
    "organizations": [
        "University of Manchester",
        "Rexresearch"
    ],
    "applications": [
        "Seawater desalination",
        "Brackish water treatment",
        "Industrial wastewater purification",
        "Radioactive waste decontamination"
    ],
    "limitations": [
        "Control of swelling under varying humidity",
        "Long-term mechanical stability of encapsulated laminates",
        "Scale-up of confinement process"
    ],
    "open_questions": [
        "How does membrane fouling affect performance over time?",
        "Can the confinement technique be applied to large-area modules?",
        "What is the energy cost of the encapsulation process at industrial scale?"
    ],
    "red_flags": [],
    "evidence_quotes": [
        "Membranes with d from ~9.8 Angstrom to 6.4 Angstrom are demonstrated, providing a sieve size smaller than the diameters of hydrated ions.",
        "Water transport is weakly affected (by a factor of <2) while ion permeation rates decrease exponentially with decreasing sieve size.",
        "The membranes exhibit 97 % rejection for NaCl.",
        "Ion permeation is thermally activated with energy barriers of ~10-100 kJ mol^-^1 depending on d.",
        "A simple scalable method to obtain graphene-based membranes with limited swelling is demonstrated."
    ],
    "category": "Nanotechnology"
}