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    Sabna V

    P100017CE

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    CONTENTS

    y CURRENT SCENARIO

    y NANOMATERIALS FOR WASTEWATER TREATMENT

    NANOSENSORS FOR THE DETECTION

    ADSORPTION OF POLLUTANTS

    MAGNETIC SEPERATION

    NANOFILTRATION FOR DESALINATION

    PHOTOCATALYTIC DEGRADATION BY OXIDATION REDUCTION

    DISINFECTION

    y SUMMARY & CONCLUSIONS

    y REFERENCES

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    CURRENT SCENARIO

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    World Stability

    Energy (biofuels for energy) Water

    Source depletion Increased water Demand

    Over useContamination

    Population growth

    Intensive agriculture

    Urbanization

    Industrial growth

    Environment requirements

    Alternate Source Additional supply

    Waste water reclamation and reuse

    Seawater desalination

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    Conventional methods of treatment

    Chemically, energetically intensive

    Infrastructure & capital engineering expertise

    Residuals (sludge, brines, toxic waste)

    Efficiency decreases due to accumulation

    Focused on large systems

    Reuse of waste water

    Not suitable for most of the world

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    Nanotechnology can play many roles

    Sensing ability

    No intensive use of chemicals Transformation of the pollutant

    Removal of low-concentration contaminants

    No production of toxic byproducts

    More efficient energy utilization Reclamation and re-use of wastewater

    Desalination of sea water

    Not capital intensive

    Large surface areas than bulk particles Possibility for functionalization with various chemical groups

    Increased affinity, capacity, and selectivity for heavy metals and other contaminants

    Enhanced reactivity, surface area and sequestration characteristics

    Size and shape-dependent optical, electronic and catalytic properties

    Selected nanomaterials water purification

    Nora, Savageand Mamadou S. Diallo, Nanomaterials and water purification:Opportunities and challenges, Journal of Nanoparticle Research (2005) 7: 331342

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    Pollution Detection and Sensing

    Inexpensive, sensitive, flexible, and portable devices for chemical and

    biological agents

    Detection of chemical markers and to amplify the signal

    Ag nanoparticle membrane array

    CNT for electrochemical sensors

    Antibiotics coated Magnetic nanoparticles specific to bacteria

    X. Chen, Y. Dong, L. Fan, D. Yang, Anal. Chim. Acta 582 (2007)281.

    W. Xu, J. Zhang, L. Zhang, X. Hu, X. Cao, J. Nanosci. Nanotechnol. 9 (2009) 4812.

    Surface-enhanced Raman scatteringSurface plasmon resonance

    Fluorescence

    Electrochemistry

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    Nano adsorption

    Weak and reversible binding of molecules or particles to a surface Activated carbon, silica gel, and alumina

    Nano adsorbents: separation media to remove inorganic and organic pollutants

    Two key properties : 1. Larger SSA than bulk particles

    2. Possibility for functionalization

    Auffan 2007, Banfield and Navrotsky 2003; El-Sayed 2001

    Larger surface area Greater sorption capacities Smaller sorbent volumes and

    Less waste for disposal

    Particle size decreases

    More exposed unsaturated

    surface atoms and

    closer functional groups

    Greater reactivity

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    Carbonaceous nanomaterials

    Nanoporous Activated Carbon Fibers (ACFs)

    Carbon Nanotubes

    Nanoporous Activated Carbon Fibers (ACFs)

    Average pore-size : 1.16 nmSurface areas : 171 to 483 m2/g

    Removed : Benzene, Toluene,

    p-xylene, ethylbenzene

    Higher organic sorption equilibrium constants than GAC

    Mangun C.L., Z.R Yue, J. Economy, S. Maloney, P. Kemme & D. Cropek, 2001. Adsorption of organic

    contaminants from water using tailored ACFs Carbon. Chem. Mater. 13, 23562360.

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    Adsorption properties of CNTs

    Chemically inert surfaces for physical adsorption

    High SSA than AC

    More well-defined & uniform atomic structure

    Well-defined adsorption sites available

    Highly porous & hollow structure

    Light mass density

    Possibility for functionalisation

    Strong interaction b/w functional groups &

    Pollutant

    Xnemei Ren, Changhun Chen, Masaaki Nagatsu, Xiangke Wang, 2010, Carbon Nnaotubes as adsorbents in

    environmenmtal pollution mamnagement: A review, CHEMICAL Enginnering Journel.

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    Precipitation

    Electrostatic attraction

    Physical adsorption depends on surface area, open-ended & defect sites

    Chemical interaction b/w metal ions and surface functional groups - Major

    Pb(II) adsorption on acidified MWCNTs

    Physical adsorption: 24.7%

    Chemical interaction : 75.3%

    Li Y.-H., J. Ding, Z.K. Luan, Z.C. Di, Y.F. Zhu, CL Xu, D.H. Wu & B.Q. Wei, 2003. Competitive adsorption of Pb2+, Cu2+ and Cd2+

    ions from aqueous solutions by multiwalled carbon nanotubes. Carbon 41(14), 27872792.

    MetalAdsorption on CNTs

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    Sorption of Pb(II), Cu(II) and Cd(II) onto MWCNTs

    97.08 mg/g for Pb(II)

    24.49 mg/g for Cu(II)

    10.86 mg/g for Cd(II)

    Metalion sorption on MWCNTs were 34 times larger than PAC and GAC

    CeO2-CNTs with 189 m2/g : effective sorbents for As(V).

    CeO2-CNTs with Ca(II) and Mg(II): As(V) (from 10 to 82 mg/g).

    Room temperature

    pH 5.0

    Metal ion eq. conc. : 10 mg/L

    Yan-Hui Li, Jun Ding, Zhaokun Luan, Zechao Dia, Yuefeng Zhu, CailuXu, Dehai Wu and Bingqing Wei, Competitive adsorption of Pb2+,

    Cu2+ and Cd2+ ions from aqueous solutions by multiwalled carbon nanotubes , Carbon Volume 41, Issue 14, 2003, Pages 2787-2792

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    Jiangnan Zhang, Zheng-Hong Huang, Ruitao Lv, Quan-Hong Yang, and Feiyu Kang, 2009, Effect of Growing CNTs onto

    Bamboo Charcoals on Adsorption of Copper Ions in Aqueous Solution, Langmuir, 25 (1), 269-274

    Effect of Growing CNTs onto

    Bamboo Charcoals

    onAdsorption of Copper Ions

    CBC700 lower than CBC800 & CBC900.

    small quantity of CNTs growth at 700 C.

    100 CBC800 16.34 mg/g twice of BC

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    Jiangnan Zhang, Zheng-Hong Huang, Ruitao Lv, Quan-Hong Yang, and Feiyu Kang, 2009, Effect of Growing CNTs ontoBamboo Charcoals on Adsorption of Copper Ions in Aqueous Solution, Langmuir, 25 (1), 269-274

    Precipitation of Cu(OH)2 at pH > 6Oxidation is favorable to ionization and ion exchange

    20CBC800 : 13.12 mg/g at Cu conc. Of 17.50mg/L

    20CBCO800 : 17.20 mg/g for oxidised CNT

    Application of CNT for organic molecule removal

    DCB maximum sorption capacity of 30.8 mg/g

    MWCNTs adsorbed volatile organic compounds than carbon black

    Alginate vesicles caged MWCNTs dyes (acridine orange, ethidium bromide, eosin

    bluish and orange G).

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    Influence of initial concentration

    Influence of pH

    Adsorption properties of Chitosan nanoparticles for Pb2+

    Influence of size

    Influence of amount

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    Other nanoparticles for metal adsorption

    Ofakaganeite [b-FeO(OH)]: As(V)

    Nanocrystalline akaganeite : Cr(VI)

    PO43- functionalized nanochitosan (40100 nm): Pb(II): 398 mg/g.

    Nanoparticles for the removal of organic molecules

    Incorporation of sodium dodecyl sulfate (SDS) into Mg - Al layered double hydroxides

    (LDHs) hybrid inorganicorganic nanosorbents

    Fullerenes and amphiphilic polyurethane nanoparticles: PAHs, naphthalene

    Qi & Su (2004), Peng et al.(2005) Deliyanni et al. (2003) , Lazaridis et al. (2005)

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    Zeolites

    Effective sorbents and ion-exchange media for metal ions.

    Na6Al6Si10O3212H2O zeolites high density of Na ion exchange sites.

    Functionalized nanoporous ceramic oxides with very large surface

    areas (1000 m2/g) and high density of sorption sites increase their

    selectivity toward target pollutants.

    Remove Cr(III), Ni(II), Zn(II), Cu(II) and Cd(II) from metal electroplating

    and acid mine wastewaters

    Moreno et al., Alvarez Ayuso et al. (2003)

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    Adsorption by TiO2

    Surface OH provides the ability to bind metal cations Solution pH influences the surface active site distribution

    +vely charged (Ti-OH1/2+) surface when solution pH < pzc on TiO2 surface

    -vely charged (Ti-OH1/2-) surface when solution pH > pzc on TiO2 surface

    Exhaustion : contaminant release from the adsorbent back into solution

    Morterra1988

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    Karen E. Engates & Heather J. Shipley, 2010, Adsorption of Pb, Cd, Cu, Zn, and Ni to titanium dioxide nanoparticles: effect of particle size,

    solid concentration, and exhaustion, Environ Sci Pollut Res

    Adsorption of Pb, Cd, Cu, Zn, and Ni to titanium dioxide nanoparticles

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    Negative adsorption : Release of

    previously adsorbed metal

    Nanoparticles exhausted in 3rd cycle but

    bulk particles in 2nd due to increased

    surface area

    Release of Ni & Cd occurred because of

    the occupation of open sites by Pb dueto its strong affinity for TiO2

    At pH= 8, adsorption increased

    due to pH> pzc

    pH= 6 Nano 1st

    Bulk 1st

    Pb 96 % 32 %

    Ni 6 % Exhaustion

    Cd 14 % Exhaustion

    Karen E. Engates & Heather J. Shipley, 2010, Adsorption of Pb, Cd, Cu, Zn, and Ni to titanium dioxide nanoparticles: effect of particle size,

    solid concentration, and exhaustion, Environ Sci Pollut Res

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    Cleaning Water with Nanorust,

    Magnetic Separation

    High magnetic gradient separation (HGMS) to remove compounds

    Magnetite (Fe3O4), maghemite (g-Fe2O3) and jacobsite (MnFe2O4) nanoparticles

    To remove heavy metals like Cr(VI), As etc. from wastewater

    Magnetic nano iron functionalized CNTs for removal of aromatic compounds and

    other organic pollutants

    Not affected by parameters such as pH, salinity and dissolved organic matter

    Coating Fe3O4 magnetic nanoparticles with humic acid can

    Greatly enhance the stability of dispersed nanoparticles by preventing their aggregation;

    Maintain the saturation magnetization by avoiding their oxidation; and

    Enlarged adsorption capacity due to carboxylic acid and phenolic hydroxyl functional groups

    Simply recovered from water with magnetic separations at very low magnetic field

    Michael Berger. Copyright 2008 Nanowerk LLC, August 19, 2008

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    As Removal using magnetic nanoparticles

    As in groundwater is a severe in Southeast Asia

    As is present in groundwater in the forms of AsO33- and AsO43-

    Resemblance with HPO32- and PO4

    3- ions: dominant source of their toxicity

    AsO33- and AsO4

    3- block ATP to ADP conversions by replacing PO43- groups

    Magnetite nanocrystals (Fe3O4)

    15 g nano Fe2O3 = 1.4 kg bulk Fe2O3 for g 500 g/l As from 50 l of water.

    Cafer T. Yavuz J. T. Mayo, Carmen Suchecki, Jennifer Wang , Adam Z. Ellsworth, Helen DCouto, Elizabeth Quevedo, Arjun Prakash, Laura

    Gonzalez, Christina Nguyen, Christopher Kelty, Vicki L. Colvin, 2010, Pollution magnet: nano-magnetite for arsenic removal from drinkingwater, Environ Geochem Health.

    12 nm

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    (a) AsIII at pH 3 and (b) AsV at pH 7 Reaction condition: 10mg/L

    AsIII or AsV adsorbed on 0.2 g/ L adsorbents in 0.01M NaNO3

    .

    Adsorption behavior of As III & As V on bimetal oxides magnetic nanomaterials

    Shengxiao Zhang, Hongyun Niu, Yuqi Lai,Xiaoli Zhao, Yali Shi, 2010, Arsenate and arsenite adsorption on coprecipitatedbimetal oxide magnetic nanomaterials: MnFe2O4 and CoFe2O4, Chemical Engineering Journel, 158, 599-607

    MnFe2O 4=138 m2/g

    Fe3O4 =102 m2/g

    CoFe2O4 =101 m2/g

    Adsorption on

    MnFe2O 4 %

    CoFe2O4 were

    twice that of Fe2

    O3

    M-OH group

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    Photo catalytic degradation

    Catalysts : promotes chemical reaction of other materials withoutbecoming permanently involved in the reaction

    Large surface areas and size and shape dependent optical,electronic and catalytic properties : catalysts and redox action

    Nano TiO2 and ZVI

    Degrade organic pollutants and

    Remove salts and heavy metals

    by Dispersed homogeneously in solution

    Deposited on to membrane structures

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    nZVI, 100 to 200 nm in dia, 33.5 m2/g consist of ZVI (Fe0).

    larger surface areas and reactivity than bulk Fe

    0

    particles Fe(H2O)6

    3+ + 3BH4 + 3H2O Fe0 + 3B(OH)3 + 10.5H2

    Reduce chlorinated alkanes , alkenes, benzenes (PCB), pesticides, organic dyes, nitro aromatics

    Reduce redox active metal ions such as Cr(VI) to less toxic Cr(III) precipitating Cr (III) hydroxides or

    Cr Fe hydroxide

    Reduce inorganic anions (e.g., nitrates).

    Dechlorination of trichloroethene

    C2HCl3 + 4Fe0 + 5H+ C2H6 + 4Fe

    2+ + 3Cl-

    Fe reactivity decrease due to precipitation of M-OH &M-CO3

    2- onto Fe surface

    Low reactiveZVI form hazardous byproducts.

    RNIP : 50/50 wt% mixture of iron and magnetite (Fe3O4).

    Core of the particles: elemental iron (-Fe)

    Outer shell : Fe3O4 surrounds Fe

    Zero Valent Iron

    Wang 1997

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    SEM images of the annealed (600 C) TiO2 thin films containing (a) Au, (b) Ag, and

    (c) Cu nanoparticles. (d) SEM image of the pure annealed TiO2 thin film at 600 C.

    Photoenhanced Degradation of Methylene Blue by TiO2- metal nanocomposites

    Parvaneh Sangpour, Fatemeh Hashemi, and Alireza Z. Moshfegh, Photoenhanced Degradation of Methylene Blue on

    Cosputtered M:TiO2 (M ) Au, Ag, Cu) Nanocomposite Systems: A Comparative Study

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    3D AFM images (1 1 m2) of the annealed (600 C) TiO2

    thin films containing (a) Au, (b) Ag, and (c) Cu nanoparticles.

    (d) AFM image of the pure annealed TiO2 thin film at 600 C.

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    Parvaneh Sangpour, Fatemeh Hashemi, and Alireza Z. Moshfegh, Photoenhanced Degradation of Methylene Blue on

    Cosputtered M:TiO2 (M ) Au, Ag, Cu) Nanocomposite Systems: A Comparative Study

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    Photo catalytic Activity

    The variation of normalized C/C0 of MB concentration as a function of UV irradiation time (a)

    without any catalyst nanoparticles. (b) TiO2 thin films containing Au, Ag, and Cu nanoparticles

    annealed at 600 C.

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    Degradation of phenol by nanomaterial TiO2

    Degradation of phenol by nanomaterial TiO2 in wastewater , Chemical Engineering Journal,Volume 119, Issue 1, 1 June 2006, Pages 55-59

    H+ or H is scavenged by

    oxygen to form HO2 radicals,which finally convert to OH

    radicals

    Complete mineralization of pollutants to CO2, water and mineral acids

    H may be produced through three routes:H2O + h

    + OH- + H+

    OH + aromatic ring, C-H bond break up, OH replaces H

    UV (472 kJ/mol) break O-H bond in H2O or phenol or C-H bond in phenol

    Fenitrothion (an agricultural organophosphorous pollutant) by immobilised nTiO2

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    y Strong oxidants (e.g., free chlorine, chloramines and ozone) are used as disinfectantsfor pathogens (e.g., bacteria and viruses)

    Impairment of cellular function by destruction of major constituents (cell wall)

    Interference with the pathogen cellular metabolic processes

    Inhibition of pathogen growth by blockage of the synthesis of key cellular

    constituents (e.g., DNA, coenzymes and cell wall proteins)

    y Formation of DBPs because of strong chemical oxidants used in water treatment.

    Trihalomethanes , Haloacetic acids & Aldehydes

    y Nanomaterials provide chlorine-free biocides.

    y functionalized nano surfaces mimic the structure and functionality of the

    receptors of target protein residues.

    y Can be designed with arrays of sites to trap all waterborne viral pathogens via

    binding to host receptors.

    Disinfection

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    Silver Nanoparticles

    Potential antimicrobial agent.

    Medical applications : Ag based dressings, Ag coated nanogels, nanolotions

    nAg by reducing AgNO3 with ascorbic acid

    Effective against Escherichia coli.

    Cellulose acetate (CA) fibers with embedded nAg

    biocides against Gram-positive and Gram-negative bacteria

    including Staphylococcus aureus, Escherichia coli, Klebsiella

    pneumoniaeand Pseudomonas aeruginosa.

    Adhesion to cell surface and cell membrane degradation by formation of pits.

    Formation of Reactive Oxygen Species (ROS) by reaction with thiol groups in

    cell protein.

    Sondi & Salopek-Sondi (2004)

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    Photoreversible antimicrobial properties of nAg

    nAg deposited on a TiO2 semiconductor support consisted of Ag2O

    Upon UV-A irradiation, e- in the VB of TiO2 move to CB, and then to nAg,

    reducing Ag+ to Ag

    Ag+ affect DNA replication and thus adenosine 5-triphosphate production

    Activity decreases with time, but can be regained by irradiation with visible light

    Photoinactivation depends on

    incident light flux and wavelength,

    absorption length through water,

    geometry, reactor hydrodynamics,

    contact efficiency of species in water on the photocatalysts

    the inactivation kinetics

    (Small2009, 5, 341344; George Xiu Song Zhao)

    TiO2 doped with N (TiON), or N & Pd can be activated with visible light inactivate

    viruses and pathogens with much lower energy

    MgO nanoparticles against Grampositive and Gram-negative bacteria (Escherichia

    coli and Bacillus megaterium) and bacterial spores (Bacillus subtillus).

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    y Peptides:

    Formation of nanochannels in cells and osmoticcollapse.

    y

    Chitosan: +vely charged Chitosan reacts with vely charged

    cell membrane.

    Penetration of cell wall and nucleus and bindingwith DNA.

    useful in acidic pH only.

    Coagulant/flocculant in water treatment systems. Low toxicity towards higher mammals and humans.

    y ZnO:

    Photocatalysis and formation of H2O2

    Penetration and degradation of cell membrane.

    y

    Fullerenes: ROS production.

    Exact mechanism still under debate.

    y CNTs:

    Physical interaction or oxidative stress whichcompromises cell membrane integrity.

    Qilin Li, Shaily Mahendra, Delina Y. Lyon, Lena Brunet,

    Michael V. Liga, Dong Li and Pedro J.J. Alvarez, Antimicrobial nanomaterials forwater disinfection and microbial control: Potential applications and implications

    y MWNTs form uniform nanoporous, cylindricalmembrane walls.

    y Mechanical stability,

    y ability to maintain constant pressure,

    y high thermal stability and

    y absence of defects.

    y packing of MWNTs in radial directions with

    respect to macrotube gives good cross flow,minimum blockage due to organic and

    inorganic pollutants.

    y E. coli bacteria > StaphylococcusAureus >

    Poliovirus Sabin 1 (25 30 nm) all can be

    filtered completely.

    y Repeated cleaning possible by ultrasonication

    and autoclaving (@121oC; 30 min.)

    y Can be operated at temperatures of 4000C

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    peptides, chitosan,

    carboxyfullerene, CNT,

    ZnO, nAg

    TiO2, ZnO and fullerol

    Chitosan

    DNA damage

    interruption of energy

    transduction (e.g. nAg and

    aqueous fullerene

    nanoparticles (nC60))

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    Nanofiltration Microfiltration, ultrafiltration, nanofiltration and Reverse Osmosis (RO).

    cations, natural organic matter, biological contaminants, organic pollutants, nitrates

    and arsenic from groundwater and surface water.y Nanomaterial membranes have more resistance to fouling, selectivity, functionality

    and permeability.

    zeolite filtration membranes and nanocatalysts and magnetic nanoparticles

    impregenated filters

    doping nAl2O

    3with Fe, Mn & La: increased selectivity &permeate flux through UF

    deposition of poly(styrene sulfonate)/poly(allylamine hydrochloride) onto porous

    alumina in NF: high water flux, high retention of divalent cations [Ca(II), Mg(II)]

    and Cl-)/SO42-) selectivity ratios up to 80

    TiO2 filter with SiO2 nanoparticles combines TiO2s photocatalytic property withnanosilicas physical barrier

    DeFriend K.A., M.R. Wiesner & A.R. Barron, 2003. Alumina and aluminate ultrafiltration membranes derived from aluminananoparticles. J. Membr. Sci. 224(12), 1128.

    TiO2 without SiO2 nanoparticles TiO2 with SiO2 nanoparticles

    large surface areas and c

    an be easily cleaned by back-flushing

    Less pressure is required to pass

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    Dendrimer-Enhanced Ultrafiltration (DEUF)

    Dendritic polymers relatively monodispersed and highly branched

    macromolecules with controlled composition and architecture consisting of

    three components: a core, interior branch cells and terminal branch cell

    removal of toxic metal ions, radionuclides, organic and inorganic solutes, bacteria & viruses

    Poly(amidoamine) (PAMAM) dendrimers with ethylene diamine (EDA) core and terminal

    NH2 to recover Cu(II) ions

    high Cu(II) binding capacities than linear polymers with amine groups.

    smaller intrinsic viscosities than linear polymers with same molar mass because of their

    globular shape

    comparatively smaller operating pressure and energy consumption could be achieved

    FrechetJ.M.J. & D.A. Tomalia, (Eds.). 2001. Dendrimers and Other Dendritic Polymers. New York: Wiley and Sons..Diallo M.S., 2004. Water treatment by dendrimer enhanced filtration. US Patent Pending. Unpublished.

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    Seawater Desalination

    Process of removing salt from sea water for the production of pure water

    USEPA standards and IS 10500: Drinking water TDS = 500 ppm

    Membrane process like RO, NF,UF, MF

    thermal desalination are the current desalination technologies

    Energy intensive (cost and environmental impact)

    Exploding energy costs and Inefficient energy utilization

    Requirement of Huge amount of land area

    CO2 emissions from the energy production

    Warmer Waste brine discharge Imbalance of marine habitats

    Reverse osmosis

    Recovery limited to ~ 50%Brine discharge (environmental concerns)

    Increased cost of pre-treatment

    Use prime (electric) energy (~ 2.5 kWh/m 3)

    Short membrane life time

    Limited chemical selectivity & Incomplete rejection

    Concentration polarization and membrane fouling

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    Diameters in the nm range

    Smooth and nearly-frictionless

    Hydrophobic walls

    Weak interactions with water Ultrafast transport of water

    High water permeability and flux

    Selectivity filter region with larger functionalgroups

    Selective ion transport

    Reduction in the cost of desalination

    High permeability

    Chemically inert membrane pore surface

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    Limitations

    Environmental fate and toxicity of a material

    Difficult to remove from the water after treatment

    Catalytic activity induce toxic effects when taken up by the cells

    Microbial degradation induce unwanted nanoparticles enter into environment

    High sorption capacity mobilises sequestered pollutants

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    CONCLUSIONS

    Nanotechnology offers much promise in water purification by monitoring,

    wastewater treatment, desalination, and purification.

    Application of water purification for drinking, disinfection, desalination, recycling

    and remediation of polluted water.

    Nanomaterials applied for water purification are carbon nanotubes,

    nanomembranes, nanoclays, zeolites, nanoscale metals and nanofibers,

    nanocatalysts, magnetic nanoparticles, nanosensors, etc.

    Nano-technology could potentially lead to more effective means of faster, moreeconomical and more selective filtration

    More research is needed for eliminating the limitations of toxicity of nanomaterials

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    Diallo M.S., 2004. Water treatment by dendrimer enhanced filtration. US Patent Pending. Unpublished.

    Frechet J.M.J. & D.A. Tomalia, (Eds.). 2001. Dendrimers and Other Dendritic Polymers. New York: Wiley and

    Sons.

    DeFriend K.A., M.R. Wiesner & A.R. Barron, 2003. Alumina and aluminate ultrafiltration membranes derived

    from alumina nanoparticles. J. Membr. Sci. 224(12), 1128.

    Qilin Li, Shaily Mahendra, Delina Y. Lyon, Lena Brunet, Michael V. Liga, Dong Li and Pedro J.J. Alvarez,

    Antimicrobial nanomaterials for water disinfection and microbial control: Potential applications and

    implications

    Degradation of phenol by nanomaterial TiO2 in wastewater , Chemical Engineering Journal, Volume 119, Issue1, 1 June 2006, Pages 55-59

    Parvaneh Sangpour, Fatemeh Hashemi, and Alireza Z. Moshfegh, Photoenhanced Degradation of Methylene

    Blue on Cosputtered M:TiO2 (M ) Au, Ag, Cu) Nanocomposite Systems: A Comparative Study

    Shengxiao Zhang, Hongyun Niu, Yuqi Lai, Xiaoli Zhao, Yali Shi, 2010, Arsenate and arsenite adsorption on

    coprecipitated bimetal oxide magnetic nanomaterials: MnFe2O4 and CoFe2O4, Chemical Engineering Journel,158, 599-607

    Cafer T. Yavuz J. T. Mayo, Carmen Suchecki, Jennifer Wang , Adam Z. Ellsworth, Helen DCouto, Elizabeth

    Quevedo, Arjun Prakash, Laura Gonzalez, Christina Nguyen, Christopher Kelty, Vicki L. Colvin, 2010, Pollution

    magnet: nano-magnetite for arsenic removal from drinking water, Environ Geochem Health

    References

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    Li Y.-H., J. Ding, Z.K. Luan, Z.C. Di, Y.F. Zhu, CL Xu, D.H. Wu & B.Q. Wei, 2003. Competitive adsorption

    of Pb2+, Cu2+ and Cd2+ ions from aqueous solutions by multiwalled carbon nanotubes. Carbon 41(14),

    27872792.

    Karen E. Engates & Heather J. Shipley, 2010, Adsorption of Pb, Cd, Cu, Zn, and Ni to titanium dioxide

    nanoparticles: effect of particle size, solid concentration, and exhaustion, Environ Sci Pollut Res.

    X. Chen, Y. Dong, L. Fan, D. Yang, Anal. Chim. Acta 582 (2007)281.

    W. Xu, J. Zhang, L. Zhang, X. Hu, X. Cao, J. Nanosci. Nanotechnol. 9 (2009) 4812.

    Jiangnan Zhang, Zheng-Hong Huang, Ruitao Lv, Quan-Hong Yang, and Feiyu Kang, 2009, Effect of

    Growing CNTs onto Bamboo Charcoals on Adsorption of Copper Ions in Aqueous Solution, Langmuir,

    25 (1), 269-274

    Yan-Hui Li, Jun Ding, Zhaokun Luan, Zechao Dia, Yuefeng Zhu, Cailu Xu, Dehai Wu and Bingqing Wei,

    Competitive adsorption of Pb2+, Cu2+ and Cd2+ ions from aqueous solutions by multiwalled carbon

    nanotubes , Carbon Volume 41, Issue 14, 2003, Pages 2787-2792

    Xnemei Ren, Changhun Chen, Masaaki Nagatsu, Xiangke Wang, 2010, Carbon Nnaotubes as

    adsorbents in environmenmtal pollution mamnagement: A review, Chemical Enginnering Journel.

    Mangun C.L., Z.R Yue, J. Economy, S. Maloney, P. Kemme & D. Cropek, 2001. Adsorption of organic

    contaminants from water using tailored ACFs Carbon. Chem. Mater. 13, 23562360.