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  • Zeolites are aluminosilicate materials commonly used as adsorbents
  • Iron core shell --- oxidized--- electron donor (so lises e-) The organic compound is reduced
  • aquifer is a wet underground layer of water-bearing permeable rock
  • Each step Cl- is knocked out Benign product ---ethene
  • 1.Borohydride is dropped into ferrous 2.Vaccum dried(figure a and b) 3. Agglomeration 4.XRD peak indicative of Fe0 not oxide!
  • 2 factor: factor 1(2 treatments- – bare and encapsulated) Factor 2: (concentration) 4 concentrations –triplicates ---2 factors(bare and encapsulated) 24 experimental k values More interested in type of NZVI Difference in treatments means (k) difference in treatment means concentration!(same type of reaction) Ho- there is no difference in means of K Ha: there is a difference in means for Conc: p=o reject Ho for bare/encapsulated : p=0.211 accept ho alpha =0.05
  • Sharanya Presentation

    1. 1. Alginate Encapsulated Nanoparticle-Microorganism System for Trichloroethylene Remediation
    2. 2. Outline <ul><li>Nanoparticles </li></ul><ul><li>NZVI and TCE </li></ul><ul><li>Need Statement, Objectives, and Hypotheses </li></ul><ul><li>Prior Work </li></ul><ul><li>Research Phase I : TCE Degradation with NZVI </li></ul><ul><li>Research Phase II : TCE degradation with Pseudomonas and NZVI </li></ul><ul><li>Research Phase III : TCE degradation with Dehalococcoides and NZVI </li></ul><ul><li>Conclusions and Future Work </li></ul><ul><li>Acknowledgements </li></ul>
    3. 3. Introduction
    4. 4. Global Nano Market US$ in Billion (2015) Source: NSF
    5. 5. Nanoparticles (NPs) <ul><li>(NPs) < 100 nm </li></ul><ul><li>NPs : Colloidal particles, Reactive species </li></ul><ul><li>NPs Classification </li></ul><ul><ul><li>Metallic (gold, iron, nickel, cobalt) </li></ul></ul><ul><ul><li>Semiconductor (quantum dots) </li></ul></ul><ul><ul><li>Polymeric (poly (L-lactic acid or PLA)) </li></ul></ul><ul><ul><li>Others (Clay NPs) </li></ul></ul>ASTM International, 2006; Liu et al., 2006
    6. 6. Applications of Nanoparticles <ul><li>Natural processes: Ubiquitous </li></ul><ul><li>Cosmetics: TiO 2 , ZnO </li></ul><ul><li>Hand Sanitizers: Ag NPs </li></ul><ul><li>Lipsticks as pigments: Iron oxide NPs </li></ul><ul><li>Dental fillers, prosthetic implants, drug carriers: SiO 2 NPs </li></ul><ul><li>Environmental applications </li></ul>
    7. 7. NPs for Environmental Remediation <ul><li>Water quality improvements </li></ul><ul><li>Treatment - contaminated soils, sediments and solid wastes </li></ul><ul><li>Halogenated/ Polychlorinated hydrocarbons, certain pesticides (DDT, lindane) </li></ul><ul><li>Hydrocarbons, dyes, and other inorganic anions such as nitrate, perchlorate, dichromate, and arsenate </li></ul><ul><li>US EPA, 2007; Thompson et al., 2010; Zhang, 2003 </li></ul>
    8. 8. NPs for Water Remediation Nanoparticles Contaminant Reference Nano Zeolites Toluene, nitrogen dioxide Song et al. (2004) Carbon nanotubes (CNTs) p-nitrophenol, benzene, toluene, heavy metal ions,dimethylbenzene Jin et al. (2007) Bimetallic nanoparticles (Pd/Fe) PCBs, chlorinated methane, ethene, Trichloroethylene (TCE) Xu and Bhattacharyya (2005) Xu and Zhao (2007) Wang and Zhang (1997) Kim et al. (2010) Ni/Fe and Pd/Au nanoparticles TCE and PCBs He and Zhao (2005) TiO 2 photocatalyst Heavy metal ions Pentachlorophenol (PCP) Pena et al. (2005) Quan et al. (2005) NZVI Herbicides (Alachlor) Thompson et al. (2010) NZVI Nitrate Bezbaruah et al. (2009) NZVI TCE Bezbaruah et al. (2011)
    9. 9. Why NZVI? <ul><li>Non-toxic and inexpensive </li></ul><ul><li>Feº is a potential reducing agent </li></ul><ul><li>Reactive species </li></ul><ul><li>High surface area </li></ul><ul><li>Can reductively degrade contaminants </li></ul>Image Credit : Matheson, and Tratnyek, 1994 Fe 0  Fe 2+ + 2e - R-X + 2e - + H +  R-H + X - Bezbaruah et al. 2009; Thompson 2010; Zhang 2003
    10. 10. Contaminant <ul><li>Trichloroethylene (TCE) </li></ul><ul><li>Solvent / Degreasing agent </li></ul><ul><li>WHY TCE? </li></ul><ul><li>Ranked as one of the most hazardous compounds (worst 10%) </li></ul><ul><li>Most commonly detected volatile organic in groundwater </li></ul><ul><li>Suspect carcinogen /Endocrine toxicant/Kidney toxicant </li></ul><ul><li>EPA permissible levels: 5 ppb </li></ul>U.S. EPA, 2011
    11. 11. TCE Contaminated Sites <ul><li>61% NPL sites contaminated with TCE </li></ul><ul><li>Valley City, ND </li></ul><ul><li>Baytown township groundwater contamination site (Minnesota) – monitored by MPCA </li></ul><ul><li>Hibbing, Minnesota </li></ul>USEPA 2007
    12. 12. In-situ Injection Injection Well Groundwater Flow TCE Contaminated plume NZVI Aquifer
    13. 13. Present Study
    14. 14. Challenges <ul><li>High mobility causes NZVI to sediment out in the aquifer pores and become unavailable for contaminant remediation </li></ul><ul><li>Existing technology for TCE removal is not efficient enough </li></ul>
    15. 15. More on TCE Remediation Methods <ul><li>Physical Methods: Expensive/Maintenance </li></ul><ul><li>Chemical Methods: By-product generation, short life span </li></ul><ul><li>Bioremediation: Slow/ Time consuming </li></ul><ul><li>There is a need to develop a more efficient method </li></ul>
    16. 16. Objectives <ul><li>To engineer a metal-microorganism system for TCE remediation </li></ul><ul><li>Specific Objectives </li></ul><ul><li>Encapsulation of NZVI (in Ca-alginate capsules) </li></ul><ul><li>TCE remediation with encapsulated NZVI </li></ul><ul><li>Encapsulation of TCE degrading bacteria </li></ul><ul><li>TCE remediation with encapsulated bacteria </li></ul><ul><li>TCE remediation with NZVI-microorganism system </li></ul><ul><li>Quantify the reaction kinetics of TCE degradation </li></ul>
    17. 17. Hypotheses <ul><li>NZVI can reduce TCE as the first step in the degradation process and then the microorganisms can preferentially take over the process </li></ul><ul><li>NZVI-microorganism system will effectively dechlorinate TCE to benign end products </li></ul>
    18. 18. TCE Degradation Mechanism - NZVI C=C Cl Cl H Cl Fe 0 Cl - e - C=C H Cl H Cl Fe 0 Cl - e - C=C H Cl H H Fe 0 Cl - e - C=C H H H H TCE DCE VC Ethene
    19. 19. Model Microorganisms <ul><li>Pseudomonas putida F1 strain </li></ul><ul><li>Capable of oxidizing organic contaminants </li></ul><ul><li>Dehalococcoides sp. </li></ul><ul><li>Reductive dechlorination </li></ul><ul><li>Converts TCE  benign products (ethene) </li></ul><ul><li>Some strains convert TCE  VC </li></ul><ul><li>D. BAV1 : TCE  Ethene </li></ul>www.miller-mccune.com http://gtresearchnews.gatech.edu/
    20. 20. Prior Work
    21. 21. P. putida F1 Interactions with NZVI Shabnam, 2011
    22. 22. E. coli 8739 interactions with NZVI
    23. 23. Experimental Design
    24. 24. Experimental Design Microorganisms Pp F1 D. BAV1 Encapsulated Microorganisms Combined NZVI-Microorganism System TCE Degradation NZVI Bare Encapsulated Encapsulated NZVI Research Phase I
    25. 25. Research Phase I Encapsulated NZVI System
    26. 26. Research Phase I <ul><li>Synthesis of NZVI </li></ul><ul><li>Preparation of Ca-alginate Capsules (Reactors) </li></ul><ul><li>Encapsulation of NZVI </li></ul><ul><li>Batch Experiments: </li></ul><ul><li>Diffusion Studies </li></ul><ul><li>TCE Degradation Studies </li></ul><ul><li>Summary </li></ul>
    27. 27. Synthesis of NZVI <ul><li>NZVI-synthesized by borohydroxide reduction method </li></ul><ul><li>2Fe 2+ + BH 4 - + 3H 2 O  2Fe 0 ↓ + H 2 BO 3 - + 4H + + 2H 2 </li></ul>TEM image of clustered nanoparticles Krajangpan et al. 2009; Bezbaruah et al. 2009; Bezbaruah et al. 2011 a b a and b : Dried NZVI XRD spectrum of NZVI
    28. 28. Encapsulation <ul><li>“ Encapsulation ” confining compounds within a matrix or membrane in particulate form </li></ul><ul><li>Encapsulated particles/compounds are free to move </li></ul><ul><li>“ Entrapment” embedding of compounds within a matrix </li></ul><ul><li>Entrapped particles/compounds are not free to move </li></ul><ul><li>Mobility and settlement problems can be overcome using NZVI </li></ul><ul><li>(Bezbaruah et al., 2009; Bezbaruah et al., 2011) </li></ul>
    29. 29. Why alginate? <ul><li>Bio-degradable </li></ul><ul><li>Non-toxic </li></ul><ul><li>Porous </li></ul><ul><li>Inexpensive </li></ul><ul><li>Used in bacterial cell immobilization </li></ul>Hill and Khan, 2008
    30. 30. Preparation of Capsules a : Capsules 30 mg NZVI 1.33% Iron loss Bezbaruah et al., 2011 b b : Encapsulated NZVI 4 g Maltodextrin 6 mL DI water 0.25 g CaCl 2 50 mL alginate Peristaltic pump Stirrer 6 cm b a
    31. 31. Batch Experiments <ul><li>DIFFUSION STUDIES </li></ul><ul><li>Empty alginate capsules used </li></ul><ul><li>45 mL reactors containing 30 and 40 mg TCE /L </li></ul><ul><li>Shaken in a rotary shaker </li></ul><ul><li>Samples (40 µL) collected over specific time intervals </li></ul><ul><li>Experiments done in triplicates </li></ul>Capsules TCE Solution 40 mL Vial
    32. 32. Diffusion Study Results <ul><li>Bulk TCE concentration decreased and then began to level off ~45 min </li></ul><ul><li>Establishes that: NO major mass transfer barrier for contaminant diffusion through Ca-alginate capsules </li></ul>
    33. 33. TCE Degradation Batch Studies Encapsulated NZVI <ul><ul><li>Samples collected over time </li></ul></ul><ul><ul><li>2 h (Rotated) </li></ul></ul>Blank Control Analysis Capsules TCE Solution TCE Solution TCE Solution + Bare NZVI
    34. 34. TCE Degradation Batch Study <ul><li>TCE removal efficiency of 88-90% using bare NZVI </li></ul><ul><li>TCE removal efficiency of 89-91% using encapsulated NZVI </li></ul><ul><li>Bare and encapsulated systems performed almost the same </li></ul>
    35. 35. TCE Degradation Kinetics TCE degradation followed First Order Kinetics for both bare and encapsulated NZVI No significant difference Bare and Encapsulated NZVI (95% CI, Two Way ANOVA ) Bezbaruah et al., 2011 Batch Initial TCE concentration mg L -1 Reaction rate constant R 2 k obs 10 -2 min -1 k sa 10 -3 L m -2 min -1 Bare NZVI 1 2.92 1.6 0.9689 10 2.35 1.3 0.9801 30 1.53 0.8 0.9897 40 2.24 1.2 0.9868 Encapsulated NZVI 1 3.23 1.7 0.9832 10 2.45 1.3 0.9491 30 1.92 1.0 0.9921 40 2.21 1.2 0.9425
    36. 36. Encapsulated NZVI: pH Observations <ul><li>pH changed from 6 to 9 as the reaction proceeded </li></ul><ul><li>Similar results irrespective of concentration </li></ul><ul><li>No NZVI – No pH change </li></ul>
    37. 37. Shelf-life Study <ul><li>Conducted over 6 months </li></ul><ul><li>Shelf-life 4 months </li></ul>
    38. 38. Research Phase I-Summary <ul><li>Encapsulated NZVI degraded 89-91% of TCE </li></ul><ul><li>Shelf-life of 4 months </li></ul><ul><li>TCE removal with NZVI followed First Order Kinetics </li></ul><ul><li>Potential scope for groundwater applications </li></ul>
    39. 39. Work Remaining Microorganisms Pp F1 D. BAV1 Encapsulated Microorganisms Combined NZVI-Microorganism system TCE Degradation NZVI Bare Encapsulated Encapsulated NZVI
    40. 40. Experimental Design Microorganisms Pp F1 D. BAV1 Encapsulated Microorganisms Combined NZVI-Microorganism system TCE Degradation NZVI Bare Encapsulated Encapsulated NZVI Research Phase II
    41. 41. Combined NZVI-Microorganism System
    42. 42. TCE Degrading Bacteria Microorganism Method of Removal End Product Reference Pseudomonas putida F1 Direct Oxidation Co-metabolism ETH (Sun and Wood 1996); (Kim et al. 2010b); (Radway et al. 1998) Clostridium bifermentans DPH-120 Co-metabolism c-DCE (Chang et al. 2000) Dehalospirillum multivorans Direct Oxidation c-DCE (Neuman et al.1994) Dehalococcoides ethenogenes 195 Reductive dechlorination ETH (Maymo-Gatell et al. 1999), (Fennell et al. 2001) Dehalococcoides BAV1 Reductive dechlorination ETH (Krajmalnik-Brown et al. 2004; Maymo-Gatell et al. 1999),(He et al. 2003) Dehalococcoides VS Reductive dechlorination ETH (Cupples et al. 2003) Dehalococcoides FL2 Reductive dechlorination ETH (El Fantroussi et al. 1998)
    43. 43. Model Microorganisms <ul><li>Pseudomonas putida F1 strain </li></ul><ul><li>Capable of oxidizing organic contaminants </li></ul><ul><li>Dehalococcoides sp. </li></ul><ul><li>Reductive dechlorination </li></ul><ul><li>Converts TCE  benign products (ethene) </li></ul><ul><li>Some strains convert TCE  VC </li></ul><ul><li>D. BAV1 : TCE  Ethene </li></ul>www.miller-mccune.com http://gtresearchnews.gatech.edu/
    44. 44. Research Phase II Combined NZVI- Pp F1 System
    45. 45. Research Phase II <ul><li>Growth Study </li></ul><ul><li>Encapsulated Pp F1 for TCE degradation </li></ul><ul><li>Encapsulated NZVI for TCE degradation in media </li></ul><ul><li>Combined NZVI- Pp F1 system </li></ul><ul><li>TCE re-dosing Experiment </li></ul><ul><li>Summary </li></ul>
    46. 46. Pseudomonas putida F1 strain <ul><li>Culture: obtained from ATCC </li></ul><ul><li>Optimal growth temperature: 30 0 C </li></ul>www.miller-mccune.com
    47. 47. Growth Curve- Pseudomonas putida F1 P. putida incubated at 30 o C in TSB media and shaken for 24 h 1 mL aliquot (0-24 h ) Serial dilution and nutrient agar plating Incubated for 24 h at 30 o C Plate count and plotting of Viable Cells/mL vs Time
    48. 48. Growth Curve <ul><li>Bacteria harvested at 12 h for TCE degradation study </li></ul>Viable cell count = Number of colonies * (1/Dilution) * (1/Volume)
    49. 49. Growth Curve – With NZVI <ul><li>Initial 3-h Lag Phase </li></ul><ul><li>5-25 h Stationary/Growth </li></ul><ul><li>26-35 h Death Phase </li></ul>
    50. 50. Pseudomonas putida F1 for TCE Degradation <ul><li>1mL of overnight culture (12 h)  encapsulated </li></ul><ul><li>Encapsulated Pp F1added to TCE in TSB media (10 mg/L) </li></ul><ul><li>Reactors shaken end-over end </li></ul><ul><li>Aliquots withdrawn at regular intervals </li></ul>
    51. 51. Pp F1 for TCE Degradation <ul><li>Encapsulated P. p F1: TCE removal efficiency of 70% </li></ul>Blank P. Pp F1+TCE
    52. 52. NZVI in Growth Media <ul><li>Purpose : To check whether NZVI behaves differently in media </li></ul><ul><li>Protocol : </li></ul><ul><li>0.75g/L NZVI +25 mL TCE solution amber vial (10mg/L TCE) </li></ul><ul><li>Rotated end-over-end at 28 rpm </li></ul><ul><li>Samples collected over time </li></ul><ul><li>Result: NZVI degrades TCE in media </li></ul>Blank NZVI + TCE (in media)
    53. 53. Batch Experiments <ul><li>Purpose: Metal-microorganism system for TCE removal </li></ul><ul><li>Batch Study Protocol: </li></ul><ul><li>Encapsulated NZVI - P. putida F1+TCE (in media) </li></ul><ul><li>Rotated – 3h </li></ul><ul><li>TCE analysis </li></ul>Encapsulated NZVI Encapsulated P.putida F1 TCE Solution 40 mL Vial
    54. 54. Re-dosing Experiments <ul><li>Purpose : To understand the individual roles of NZVI and Pp F1 </li></ul>Rotated End-over-end for 3h Remove TCE solution Add new TCE solution Rotated End-over-end 36 h Aliquots Analysis
    55. 55. Results <ul><li>TCE degradation 0-3h (NZVI dominated) </li></ul><ul><li>TCE degradation 3-36h (Bacteria dominated) </li></ul>Add new TCE Solution
    56. 56. NZVI Re-dosing <ul><li>No TCE removal after 3 h </li></ul>
    57. 57. Kinetic Studies <ul><li>E-NZVI: Encapsulated NZVI, E-B: Encapsulated Bacteria, C-NZVI: Combined System (NZVI dominated), C-B: Combined system (bacteria dominated) </li></ul>
    58. 58. Research Phase II- Summary <ul><li>Metal-Microorganism system was successfully designed </li></ul><ul><li>Pp F1 and NZVI were encapsulated separately </li></ul><ul><li>TCE was completely removed after 3 h (~ 100%) (NZVI dominated) and ~70% (bacteria dominated) in 36 h after re-dosing </li></ul>
    59. 59. Work Remaining TCE Degradation NZVI Bare Encapsulated Encapsulated NZVI Microorganisms Pp F1 D. BAV1 Encapsulated Microorganisms Combined NZVI-microorganism system Research Phase III
    60. 60. Research Phase III Combined NZVI- D BAV1 System
    61. 61. Research Phase III <ul><li>Growth Study </li></ul><ul><li>Encapsulated DBAV1 for TCE degradation </li></ul><ul><li>Encapsulated NZVI for TCE degradation in media </li></ul><ul><li>Combined NZVI- DBAV1 system </li></ul><ul><li>TCE re-dosing Experiment </li></ul><ul><li>Summary </li></ul>
    62. 62. Dehalococcoides BAV1 <ul><li>Anaerobic bacteria </li></ul><ul><li>Method: Reductive dechlorination </li></ul><ul><li>Capable of reducing TCE  ethane </li></ul><ul><li>Culture obtained from ATCC </li></ul>
    63. 63. D .BAV1 growth Studies D. BAV1 incubated at 22±2 o C in (MSM) media and shaken 1 mL aliquot at regular interval (0-36 h ) Serial dilution and nutrient agar plating Incubated for 24 h at 22±2 o C Plate count and plotting of Viable Cells/mL vs Time
    64. 64. D . BAV1 Encapsulation
    65. 65. TCE Degradation Batch Studies Combined metal-microorganism Encapsulated D.BAV1 Encapsulated NZVI (re-dosed) Encapsulated NZVI
    66. 66. pH-ORP Data Acquisition System
    67. 67. pH-ORP Change <ul><li>ORP- Reducing conditions </li></ul><ul><li>Increase at 3 h – exposure to air </li></ul><ul><li>pH- initial increase (reaction with NZVI) </li></ul><ul><li>Constant throughout the reaction </li></ul>
    68. 68. Kinetic Study
    69. 69. Research Phase III -Summary <ul><li>D BAV1and NZVI were co-encapsulated </li></ul><ul><li>TCE was completely removed after 3 h (~ 100%) ( NZVI dominated ) </li></ul><ul><li>After re-dosing TCE removal ~ 100% ( Bacteria dominated ) </li></ul><ul><li>First order kinetics </li></ul>
    70. 70. Conclusions <ul><li>Encapsulation of NZVI in alginate polymer : viable for TCE dechlorination </li></ul><ul><li>Encapsulation of microorganisms in alginate polymer : efficient technique for TCE removal </li></ul><ul><li>DCE and VC: not detected </li></ul><ul><li>Combined metal-microorganism was successful with the advantages of both NZVI and microorganisms </li></ul><ul><li>Potential for in-situ remediation applications (e.g., PRBs) </li></ul>
    71. 71. Future Directions <ul><li>Interferences of other groundwater contaminants (electrons acceptors like nitrate and dissolved oxygen) </li></ul><ul><li>Shelf-life of the combined NZVI-microorganism system </li></ul><ul><li>The roles of NZVI and bacteria in a combined system </li></ul><ul><li>Make it versatile (Other Contaminants) </li></ul>
    72. 72. Acknowledgements <ul><li>ND Water Resource Research Institute </li></ul><ul><li>Department of Civil Engineering </li></ul><ul><li>Dr. Achintya Bezbaruah </li></ul><ul><li>Dr. Eakalak Khan </li></ul><ul><li>Dr. Senay Simsek </li></ul><ul><li>Dr. G. Padmanabhan </li></ul><ul><li>NRG Group </li></ul><ul><li>Members of the Environmental Engineering Laboratory </li></ul>
    73. 73. <ul><li>Thank you! </li></ul>

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