AIR – WATER PARTITIONING OF VOLATILE ORGANIC COMPOUNDS AND GREENHOUSE GASES IN THE PRESENCE OF SALTS A Thesis Presented to The Academic Faculty by James Benjamin Falabella In Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the School of Chemical and Biomolecular Engineering Georgia Institute of Technology August 2007 Copyright © 2007 James B. Falabella AIR – WATER PARTITIONING OF VOLATILE ORGANIC COMPOUNDS AND GREENHOUSE GASES IN THE PRESENCE OF SALTS Approved by: Dr. Amyn S. Teja, Chair Dr. Charles A. Eckert School of Chemical and Biomolecular School of Chemical and Biomolecular Engineering Engineering Georgia Institute of Technology Georgia Institute of Technology Dr. James Frederick Dr. Athanasios Nenes School of Chemical and Biomolecular School of Chemical and Biomolecular Engineering Engineering and School of Earth and Georgia Institute of Technology Atmospheric Sciences Georgia Institute of Technology Dr. Paul H. Wine School of Chemistry and Biochemistry and School of Earth and Atmospheric Sciences Georgia Institute of Technology Date Approved: April 30, 2007 To my Family ACKNOWLEDGEMENTS I would like to thank my PhD thesis advisor Professor Amyn S. Teja for the guidance and experience that he has shared with me during my time in his research group. I would also like to thank Professors Eckert, Frederick, Nenes, and Wine of my reading committee for their critical reviews of my research. Dr. Tongfan Sun’s advice on thermodynamic modeling helped me to efficiently sort through the literature. I truly appreciate Dr. Xin-Sheng Chai’s headspace gas chromatography advice, which helped me have a quick start in measuring the necessary Henry’s constants. All of my family members, particularly my parents and sister, have been a key source of moral support during my journey through graduate school. My MS thesis advisor at Northeastern University, Professor Nurcan Baç, has helped me build a strong foundation for graduate work in the two years that I spent in his research group. Imogene Baker, Gayle Burt, and Rochelle Moses in the School of Chemical and Biomolecular Engineering helped me procure the chemicals and equipment for my research and their very prompt ordering kept my project on schedule. Advice and writing exercises from Jacqueline Mohalley-Snedeker of the ChBE writing program and Karen Head of the Center for the Enhancement of Teaching and Learning (CETL) have helped me further refined my technical writing skills. Teja group members Michael Beck, Anupama Kasturirangan, Pei Yoong Koh, Angel Olivera Toro, and Chunbao Xu have been great friends and coworkers. I truly appreciate the financial support provided by the Institute of Paper Science and Technology over the entire course of my project. iv TABLE OF CONTENTS Page ACKNOWLEDGEMENTS............................................................................................... iv LIST OF TABLES...........................................................................................................viii LIST OF FIGURES ............................................................................................................ x LIST OF SYMBOLS ....................................................................................................... xiv SUMMARY.................................................................................................................... xvii Chapter 1. Introduction............................................................................................................. 1 2. Literature Review....................................................................................................8 2.1 Literature sources of Henry’s constants in ternary systems.......................... 8 2.2 Limiting activity coefficients for water + salt + VOC systems in the literature ...................................................................................................... 11 2.3 Vapor liquid equilibrium data. .................................................................... 13 2.4 Measurement Methods................................................................................ 15 2.4.1 Determining infinite dilution activity coefficients in water + salt + VOC systems at ambient pressure. ....................................................................... 15 2.4.2 Determining Henry’s constants at ambient pressure................................... 18 2.4.2.1 Purge and trap.............................................................................................. 18 2.4.2.2 Sealed vial methods..................................................................................... 19 2.4.3 Determining Henry’s constants at high pressures. ...................................... 22 2.5 Modeling the solubility of nonelectrolytes in aqueous systems.................. 23 2.5.1 Correlating Henry’s constants in water-VOC systems ............................... 23 2.5.2 Modeling Setchenov constants.................................................................... 26 2.5.2.1 Electrostatic models for predicting the Setchenov constant........................ 29 2.5.2.2 Group contribution model for predicting Setchenov constants................... 39 v 2.6 Dilute solution theory for water + salt + VOC mixtures............................. 41 2.6.1 Models for activity coefficients of water + salt + VOC systems. ............... 48 3. Headspace gas chromatography methods ............................................................. 61 3.1 Indirect differential headspace gas chromatography................................... 61 3.2 Validation of Henry’s constants from the differential method.................... 62 3.3 Modified relative method of headspace gas chromatography of salt containing solutions..................................................................................... 65 3.4 Time for equilibration ................................................................................. 67 3.5 Phase ratio selection for the relative method .............................................. 69 3.6 Validation of relative headspace method against the differential method .. 71 4. Measurement of Henry’s constants with headspace gas chromatography............ 74 4.1 Apparatus .................................................................................................... 74 4.2 Materials...................................................................................................... 76 4.3 Procedures ................................................................................................... 79 4.3.1 Systems explored with the relative method................................................. 79 4.3.1.1 2-Ketones with sodium sulfate.................................................................... 79 4.3.2 Henry’s constants from the differential method.......................................... 81 4.3.2.1 Aromatics, ethers, and sulfides ................................................................... 81 4.3.2.2 2-Ketones with tetraalkylammonium bromide salts.................................... 83 4.3.2.3 2-Ketones with mixtures of sodium sulfate and sodium chloride............... 84 4.4 Results: Measured Henry’s constants. ........................................................ 85 4.4.1 2-Ketones + water + Na2SO4....................................................................... 85 4.4.2 Transportation fuel components and organic sulfides............................... 100 4.5 Error analysis............................................................................................. 105 5. Thermodynamic Modeling..................................................................................106 5.1 Henry’s constants at different pressures.................................................... 106 vi 5.1.1 Error analysis for the parameters of Eq. 148............................................. 108 5.1.2 Results for high-pressure ternary systems................................................. 112 5.2 Estimation of methane emissions from produced water. .......................... 121 5.3 Correlation of ambient pressure ternary systems ...................................... 124 5.4 Regression of Henry’s constants of o-xylene + water + NaCl.................. 130 5.5 Regression of Henry’s constants of organic sulfides + water + Na2SO4 .. 132 5.6 Regression of Henry’s constants of 2-ketones + water + tetraalkylammonium bromide salts. .......................................................... 134 5.7 Regression of Henry’s constants of 2-ketones + water + Na2SO4. ........... 138 5.8 Regression of Henry’s constants of 2-ketones + water + NaCl. ............... 140 5.9 Regression of Henry’s constants of 2-ketones + water + NaCl / Na2SO4 mixtures..................................................................................................... 142 5.10 Regression of Henry’s constants of 1-alkanols + water + Na2SO4. .......... 145 5.11 Trends in regression parameters................................................................ 147 5.12 Trends of D with molecular size for homologous series of 1-alkanols and 2- ketones....................................................................................................... 152 6. Conclusions and recommendations..................................................................... 158 Appendix A: Procedure for Headspace gas chromatography......................................... 162 Appendix B: Error analysis for the relative and differential methods...........................