Superwetting nanowire membranes for selective absorption
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Superwetting nanowire membranes for selective absorption. Authored by Jikang Yuan, Xiaogang Liu, Ozge Akbulut, Junqing Hu, Steven L. Suib, Jing Kong and Francesco Stellacci. Presented by Bryce Smith, Neal Mistry, Elliot Young, and Kyle Hamaker. Problem.

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Superwetting nanowire membranes for selective absorption

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Superwetting nanowire membranes for selective absorption

Superwetting nanowire membranes for selective absorption

Authored by Jikang Yuan, Xiaogang Liu, Ozge Akbulut, Junqing Hu, Steven L. Suib, Jing Kong and Francesco Stellacci

Presented by Bryce Smith, Neal Mistry, Elliot Young, and Kyle Hamaker


Problem

Problem

  • Need new ways to combat water pollution

    • Oil spills

    • Industrial pollution

    • Water contaminants

Source: http://www.freedrinkingwater.com/images-new/education-page/image/algae-lake.jpg


Purpose

Purpose

Construction method of nanoporous membranes for:

  • Catalyst Supports

  • Filters for Biomolecule Purification

  • Seawater desalination

    Construct a nanowire membrane that is:

  • thermally stable

  • controlled wetting behaviour ranging from superhydrophilic to superhydrophobic


What has been done

What has been done?

BP Oil Spill - Chemical Dispersants

  • Breaks down oil into smaller droplets

    Magnets and Nanotechnology

  • water-repellent nanoparticles that contain iron

    Cloth Coated with Chemical Polymer

  • both hydrophilic and oleophobic

http://upload.wikimedia.org/wikipedia/commons/6/61/C-130_support_oil_spill_cleanup.jpg


Procedure

Procedure

  • Manganese Oxide

    Autoclave

    manganese sulfate,

    potassium sulfate,

    potassium persulfate

    DI water

    Teflon

  • 3D porous nanostructures

    • capillary action

  • Oleophobic

  • Cryptomelane pore size = 10nm, 44 m2 g-1

1:2:1

Image: Yuan, J., Laubernds, K., Villegas, J., Gomez, S. & Suib, S. L. Spontaneous formation of inorganic paper-like materials. Adv. Mater. 16, 1729–1732 (2004).


Procedure1

Procedure

  • Coating of silane = superhydrophobic

    • Vapor deposition

      Polydimethysiloxane (PDMS)

      Cooling 234°C, 30min

      Heating 390°C

      Silicone coating

Image: Barron, Andrew R. "Chemical Vapor Deposition." OpenStax CNX. Rice University, n.d. Web. 21 Sept. 2014.


Non coated membrane

Non-Coated Membrane

  • Optical image of membrane

  • SEM image of cross-sectional area

  • SEM image of surface morphology of membrane

  • SEM image of nanowire networks

  • Close up SEM of nanowire bundle

  • TEM of single cryptomelane nanowire

  • Close-up view of f)

  • Wetting time vs. # water droplets deposited over a time interval

Figure adapted from reference 1.


Water contact angle

Water contact angle

Figure adapted from http://www.funsci.com/fun3_en/exper2/exper2.htm


Silane coated membrane

Silane-coated membrane

  • Water contact angle

  • SEM image of nanowires coated in silicone

  • TEM image of modified nanowires

  • High-magnification TEM image of silicone coating on nanowire

  • EDS spectrum

    Cryptomelane: K(Mn4+,Mn2+)8O16

    PDMS: (C2H6OSi)n

Figure adapted from reference 1


Surface wetting switchability

Surface wetting switchability

  • Representation of reversible wettability

  • Contact angle and hysteresis measurements taken after each transition cycle

Figure adapted from reference 1


Wettability

Wettability

  • Absorption capacities for different organic solvents and oils

b,c)Layer of blue-dyed gasoline being removed by membrane

Figure adapted from reference 1


Analysis

Analysis

  • Wettability is highly switchable

  • Mechanically robust - resists repeated ultrasonic treatment

  • Silane coating not the only reason for superhydrophobic behavior

  • Highly effective selective superabsorbance

  • Reusable


Applications

Applications

  • Removal of oil from water in case of oil spills

  • Detection of solutes with similar polarities in a solution

http://www.safety4sea.com/ship-execs-in-trouble-over-oil-spill-13790


Oil spill

Oil Spill

  • Absorbs oil while leaving water behind

  • Using ultrasonic washing, the membrane releases the oil and allows for reuse of both oil and material


Chromatography

Chromatography

The massive surface area of the nanotube membrane magnifies the difference in polarity of similar solutes in a solution

Leads to better detection of pollutants


Example solutes

Example Solutes

TOLUENE

BENZENE

http://iaspub.epa.gov/tdb/pages/contaminant/contaminantOverview.do?contaminantId=10140

http://commons.wikimedia.org/wiki/File:Toluene.png


Chromatography data

Chromatography Data

Figure adapted from Reference 1


References

References

1.Yuan, Jikang, Xiaogang Liu, Ozge Akbulut, Junqing Hu, Steven L. Suib, Jing Kong, and Francesco Stellacci. Superwetting Nanowire Membranes for Selective Absorption (2008): 332-36. Web. 19 Sept. 2014.

2.Barron, Andrew R. "Chemical Vapor Deposition." OpenStax CNX. Rice University, n.d. Web. 21 Sept. 2014.

3. Levitt, Tom. "Cleaning up Oil Spills with Nanotechnology and Magnets." CNN. CNN, 21 Sept. 2012. Web. 21 Sept. 2014.

4.Rutherglen, Chris, Dheeraj Jain, and Peter Burke. "Nanotube Electronics for Radiofrequency Applications."

Nature.com. Nature Publishing Group, 29 Nov. 2009. Web. 19 Sept. 2014.

5."Seven Technologies Used to Clean the Gulf Oil Spill." CBSNews. CBS Interactive, 5 May 2010. Web. 21 Sept. 2014.


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