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Membrane-Based Nanostructured Metals for Reductive Degradation of Hazardous Organics at Room Temperature. D. Bhattacharyya (PI)*, D. Meyer, J. Xu, L. Bachas (Co-PI), Dept. of Chemical and Materials Engineering and Dept. of Chemistry, University of Kentucky, and S. Ritchie (Co-PI), L. Wu,

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slide1

Membrane-Based Nanostructured Metals for Reductive Degradation of Hazardous Organics at Room Temperature

D. Bhattacharyya (PI)*, D. Meyer, J. Xu, L. Bachas (Co-PI),

Dept. of Chemical and Materials Engineering and Dept. of

Chemistry, University of Kentucky, and S. Ritchie (Co-PI), L. Wu,

Dept. of Chemical Engineering, Univ. of Alabama

* email: db@engr.uky.edu

* phone: 859-257-2794

Project Officer: Dr. Nora Savage, US EPA

EPA Nanotechnology Grantees Workshop

August 17-20, 2004

slide2

Functionalized Materials and

Membranes

(Nano-domain Interactions)

Tunable

Separations

(with Polypeptides)

Hollman and Bhattacharyya, LANGMUIR

(2002,2004); JMS (2004)

Smuleac, Butterfield, Bhattacharyya,

Chem. of Materials (2004)

Reactions and Catalysis

(nanosized metals,

Vitamin B12, Enzymes)

Ultra-High

Capacity Metal

Sorption (Hg, Pb etc)

Bhattacharyya, Hestekin, et al, J. Memb. Sci. (1998)

Ritchie, Bachas, Sikdar, and Bhattacharyya, LANGMUIR (1999)

Ritchie, Bachas,Sikdar, and Bhattacharyya, ES&T (2001)

*Ahuja, Bachas, and Bhattacharyya, I&EC (2004)

slide3

Why Nanoparticles?

  • High Surface Area
  • Significant reduction in materials usage
  • Reactivity (role of surface defects, role of dopants such as, Ni/Pd)
  • Polymer surface coating to alter pollutant partitioning
  • Alteration of reaction pathway (ex, TCE -- ethane)
  • Bimetallic (role of catalysis and hydrogenation,
  • minimizing surface passivation)
  • Enhanced particle transport in groundwater
synthesis of metal nanoparticles in membranes and polymers
Synthesis of Metal Nanoparticles in Membranes and Polymers
  • Chelation (use of polypeptides,poly(acids), and polyethyleneimine)
    • Capture and borohydride reduction of metal ions using polymer films containing polyfunctional ligands.
  • Mixed Matrix Cellulose Acetate Membranes
    • Incorporation of metallic salts in membrane casting solutions for dense film preparation. Formation of particles within the membrane occurs after film formation.
    • External Nanoparticle synthesis followed by membrane casting
  • Thermolysis and Sonication
    • Controlled growth of metal particles in polymeric matrices by decomposition of metal carbonyl compounds thermally or by sonication.
  • Di-Block Copolymers
    • The use of block copolymers containing metal-interacting hydrophilic and hydrophobic segments provide a novel approach for in-situ creation of nanostructured metals (4-5 nm) in the lamellar space of self-assembled thin films.
preparation of supported iron nanoparticles
Preparation of supported iron nanoparticles
  • Synthesis reaction:

5 ml NaBH4 (5.4M) solution drop-wisely

N2 in

N2 out

Mixing

Casting

Water in oil micelle

CA acetone solution

Iron naoparticlesin Cellulose acetone solution

Washed using methanol

Iron nanopartilces

Ethanol bath

  • The weight content of iron is 6.6% by AA (Atomic Absorption).
tem characterization of pre produced iron particles
TEM Characterization of pre-produced iron particles
  • TEM bright field image of pre-produced iron particles
  • TEM bright field image of CA membrane-supported iron nanoparticles
mixed matrix membrane preparation

Cellulose Acetate in Acetone

Fe2+/Ni2+ (aq)

NaBH4(aq or ethanol)

Mixed-Matrix Membrane Preparation

Phase Inversion

Wet Process (nonsolvent gelation bath)

Water or ethanol

Dry Process

Cellulose Acetate/Fe2+/Ni2+ Mixed-Matrix Membrane

Reduction

Cellulose Acetate/Nanoscale Fe-Ni Mixed-Matrix Membrane

Meyer, Bachas, and Bhattacharyya, Env. Prog (2004)

slide9

M2+ + PAA-Na+ M2+-PAA + Na+

COO-

COO-

COO-

Mo: Nanosized Mo in membrane phase

Nano-structured Metal Formation and Hazardous Organic Dechlorination with Functionalized Membranes (with simultaneous recapture/reuse of dissolved metals).

Metal Reduction

(Borohydride or electrochemical)

M2+ Recapture with membrane-bound PAA Carboxylic Groups

(loss of metals and metal hydroxide pptn. On Mo surface prevented)

Mo + PAA

PAA:Poly-amino acid

Or Poly-acrylic acid

Selective Sorption

Chlorinated organics in water R-Cl

Mo M2+ + 2e-

In Membrane

R-Cl + H+ + 2e- R-H + Cl-

slide10

Nanoparticle Synthesis in Membrane (use of PAA)

Nano Fe/Ni or Fe/Pd particles immobilized in membrane

Membrane support

Cross-section

Post coating with Ni or Pd

Polyether sulfone

(PES)

Polyvinylidene

fluoride (PVDF)

PAA+Fe2++EG

Dip Coating

NaBH4 solution

Ethylene glycol

(EG)

Polyacrylic acid (PAA)

110 °C 3 hour

Uncrosslinked PAA-Fe2+

Crosslinked PAA-Fe2+

slide11

A

B

(A) SEM surface image of nanoscale Fe/M particles immobilized in PAA/MF composite membrane (reducing Fe followed by metal deposition) (100,000); (B) Histogram from the left SEM image of 150 nanoparticles. The average particle size is 28 nm, with the size distribution standard deviation of 7 nm.

slide13

Reducing Fe followed by Ni deposition

Fe

Fe

Ni

Ni

Simultaneous reduction of Fe and Ni

STEM-EDS Mapping (using JOEL 2010)

slide14

TCE Dechlorination by Fe/Ni and Fe/Pd

Nanoparticles in Membrane

Metal loading:45mg/40mL

Initial TCE: 10µg/ml

Fe: Ni= 4:1 (in PES support)

slide15

C: TCE concentration

kSA: surface-area-normalized reaction rate

as: specific surface area

m: mass concentration of metal

t: time

()Fe/Ni (simultaneous reduction);

()Fe/Ni (Ni deposition on Fe);

()Fe/Ni (solution phase)

() Fe/Pd

Surface-Area-Normalized Dechlorination Rate (wide variation of kSA showing the importance of surface – active sites and role of hydrogenation)

Fe/Ni

Fe/Pd

Other source kSA*

* From B. Schrick, J.L. Blough, A.D. Jones, T.E. Mallouk, Hydrodechlorination of Trichloroethylene to Hydrocarbons Using Bimetallic Nickel-Iron Nanoparticles. Chem.Mater. 2002, 14, 5140-5147.

slide16

Effect of Ni content in Fe/Ni particles on KSA

Initial TCE: 20mg/L

Reaction volume: 110mL

Fe/Ni in PVDF support (Posting coating Ni)

Fe

Ni

All experiments were performed in batch systems using nanosized Fe/Ni particles (Post coating Ni) immobilized in PAA/PVDF membrane.

slide17

Main intermediates at short time: 2,5,2’-trichlorobiphenyl, 2,2’-dichlorobiphenyl, 2-chlorobiphenyl

Metal loading:22mg/20mL

Pd = 0.4 wt%

Initial organic concentration:8.4mg/L

in 50% ethanol/water

Reactions of 2,3,2’,5’-Tetrachlorobiphenyl (PCB)with Fe/Pd (~30 nm) in PAA/PVDF membrane

slide18

Dechlorination Study under Convective Flow Mode(PVDF-MF membrane & Fe/Pd nanoparticles)

  • 22 mg Fe/Pd (Pd=0.4wt%) in PAA/PVDF
  • membrane (4 samples of membranes in stack)
  • Membrane area = 13.5 cm2
  • Membrane thickness = 125m  4
  • Membrane Permeability = 210-4 cm3cm-2bar-1s-1
  • Pressure:0.3~4 bar

2,2’- Chlorobiphenyl Degradation

acknowledgements
Acknowledgements
  • US EPA- STAR Program Grant # R829621
  • NSF-IGERT Program
  • NIEHS-SBRP Program
  • Dow Chemical Co.
  • Undergrads: UK--Melody Morris, Morgan Campbell, Alabama--Cherqueta Claiborn