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

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

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  1. 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

  2. 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)

  3. 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

  4. 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.

  5. 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).

  6. 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

  7. Change of chloride ions in aqueous phase (TCE degradation to Cl-)

  8. 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)

  9. 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-

  10. 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+

  11. 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.

  12. Image of Fe/Ni particles Prepared in a TEM Grid (Ni post-Coated) 50.8 nm

  13. Reducing Fe followed by Ni deposition Fe Fe Ni Ni Simultaneous reduction of Fe and Ni STEM-EDS Mapping (using JOEL 2010)

  14. 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)

  15. 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.

  16. 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.

  17. 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

  18. 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

  19. 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

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