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Paul Mines 1,2 , Jeehye Byun 2 , Y. Hwang 1 , H. Patel 2 , H. Andersen 1 , C. Yavuz 2

<8 TH Annual Meeting of DWRIP 2014, January 30 >. Hybrid composites of nano-sized zero valent iron and covalent organic polymers for groundwater contaminant degradation. Paul Mines 1,2 , Jeehye Byun 2 , Y. Hwang 1 , H. Patel 2 , H. Andersen 1 , C. Yavuz 2.

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Paul Mines 1,2 , Jeehye Byun 2 , Y. Hwang 1 , H. Patel 2 , H. Andersen 1 , C. Yavuz 2

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  1. <8TH Annual Meeting of DWRIP 2014, January 30> Hybrid composites of nano-sized zero valent iron and covalent organic polymers for groundwater contaminant degradation Paul Mines1,2, Jeehye Byun2, Y. Hwang1, H. Patel2, H. Andersen1, C. Yavuz2 1 Department of Environmental Engineering, DTU, Denmark 2Graduate School of Energy, Environment, Water and Sustainability, KAIST, Korea

  2. Introduction – Nano-sized Zero Valent Iron (nZVI) Extremely effective at degrading a wide variety of contaminants in water sources • Chlorinated organics, azo dyes, pesticides, inorganic ions • Compounds are often not amenable to biodegradation Reaction scheme for nZVI with chlorinated organics: Ref: Daniel Cha, U. of Delaware TCE acetylene ethene ethane

  3. Introduction – nZVI Stabilization Conventional technology – permeable reactive barriers(PRBs) • Limited by stability of ZVI in groundwater • Fe0 aggregates together, forms large particles, settles out, becomes inactive Widespread application requires that nZVI remains stable and maintains its reactivity • Applicable for in situ PRBs or ex situ pump-n-treat operations PRB Ref: EnviroMetal, Inc. Ref: PNF Nano-Engineering & Manufacturing Co.

  4. Introduction – Covalent Organic Polymers (COPs) • Hybrid materials improving on conventional covalent organic framework (COF) technology at lower cost. • No post-processing or cross-linking necessary • Offer extremely high surface areas • Up to 600 m2/g • Proven adsorbent for CO2 capture applications • Up to 5600 mg-CO2/g-COP (@200bar/318K) (Patel et al., 2012)

  5. COP Chemistry

  6. Overall Objectives • Stabilization • Prove feasibility of COP materials as effective supporting and stabilizing agents for nZVI • Remediation of azo dyes • Poses significant environmental risk due to toxicity and widespread global application • Acts as model pollutant for degradation of other recalcitrant chemicals • Prove a synergistic effect of the composite material • Show effective decolorization of azo dye with COPs • Combining adsorption from COP material and degradation from impregnated nZVI • Eventual target  halogenated organics (TCE, PCE, etc.)

  7. Materials and Methods 1. Synthesis of nZVI impregnated COPs

  8. Materials and Methods 2. Characterization • Transmission electron microscopy (TEM) • Inductively coupled plasma – mass spectrometry (ICP-MS) • Total iron content within composites • X-ray diffraction (XRD) • Confirmation of presence of Fe0 • BET surface area 3. Stabilization Test • Optical absorbance at 508nm using UV-Vis spectrometer (Phenrat et al., 2007) 4. Reactivity Test • Azo-dye decolorization - Acid Black I (60µM) / HEPES buffered (10mM) - Reaction solution: 1.5g composite/L dye solution

  9. TEM Imaging COP6/nZVI COP19/nZVI

  10. Iron Contained in Composites (ICP-MS)

  11. Presence of Fe0 (XRD) Pure nZVI COP19/nZVI

  12. Composite BET Surface Area Analysis

  13. Composite Stability Testing Sedimentation Test • Optical absorbance @ 508nm COP/nZVI composites show increased stability vs. pure nZVI

  14. Acid Black I Decolorization Images Alias: Naphthol blue black Molecular Formula: C22H14N6Na2O9S2 Molecular Weight: 616.499 g/mol Peak Absorbance (λmax): 618nm COP1/nZVI t=0 t=30 D.I. 1,2,7-triamino- 8-hydroxynaphthalene- 3,6-disulfonate COP19/nZVI t=0 + t=30 D.I. aniline + COP60/nZVI t=30 D.I. t=0 p-nitro-aniline p-phenylene-diamine

  15. Dye Decolorization UV-Vis Spectra COP1 COP1/nZVI • Combination of dye adsorption and degradation COP19/nZVI • Primarily dye adsorption COP60/nZVI • Little to no adsorption or degradation COP19 COP60

  16. Acid Black I - Peak Absorbance vs. Time

  17. COP6: Polymer vs. Composite Decolorization

  18. Surface Area vs. Decolorization

  19. Conclusions nZVI/COP Synthesis • Successfully impregnated nZVI within the COP matrices (~10%) Effective Stabilization of nZVI • Loading nZVI into the COP matrix proves much more stable than bare nZVI Successful Azo Dye Decolorization • Depending on the COP, achieved decolorization in the form of adsorption, degradation, or a combination of both Wettability of the Polymer • Decolorization is highly dependent on the wettability of the COP material • Migration of the azo dye in the aqueous phase must be possible and depends on the nature of the composite material Surface Area of the Composite Material • Decolorization is also dependent on the total surface area of the nZVI/COP material

  20. Thank you for attention Any questions & comments?

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