STUDY OF PLASMA AND ELECTROSTATIC PROCESSES IN ENVIRONMENTALLY RELEVANT PHENOMENA by JOSEPH ROBERT TOTH Submitted in partial fulfillment of the degree requirements for the degree of Doctor of Philosophy Department of Chemical and Biomolecular Engineering CASE WESTERN RESERVE UNIVERSITY January, 2021 CASE WESTERN RESERVE UNIVERSITY SCHOOL OF GRADUATE STUDIES We hereby approve the thesis of JOSEPH ROBERT TOTH candidate for the degree of Doctor of Philosophy.* Committee Chair R. Mohan Sankaran Committee Member Julie Renner Committee Member Christian A. Zorman Committee Member Daniel Lacks Date of Defence August 3, 2020 *We also certify that written approval has been obtained for any proprietary material contained therein. Table of Contents Table of Contents ................................................................................................................. I List of Tables ..................................................................................................................... V List of Figures ................................................................................................................... VI Acknowledgements .......................................................................................................... XII Abstract ............................................................................................................................... 1 Chapter 1: Introduction ....................................................................................................... 2 1.1 Triboelectric charging of identical insulating particles ........................................ 2 1.2 Electrostatic effects on dust transport .................................................................. 4 1.3 Plasma reactor design for methane conversion .................................................... 6 1.4 Hydrogen gas evolution at an electrified plasma-water interface ........................ 9 1.5 Ammonia synthesis from a plasma-water system .............................................. 11 Chapter 2: Triboelectric charging of identical insulators ................................................. 14 2.1 Introduction ........................................................................................................ 14 2.2 Methods .............................................................................................................. 15 2.2.1 Experimental ................................................................................................... 15 2.2.2 Modeling ......................................................................................................... 17 2.3 Results and discussion ........................................................................................ 19 2.3.1 Experimental results ....................................................................................... 19 2.3.2 Modeling results ............................................................................................. 22 I 2.3.3 Discussion ....................................................................................................... 25 2.4 Conclusion .......................................................................................................... 27 Chapter 3: Electrostatic effects on dust transport ............................................................. 28 3.1 Introduction ........................................................................................................ 28 3.2 Methods .............................................................................................................. 28 3.2.1 Experimental ................................................................................................... 28 3.2.2 Modeling ......................................................................................................... 30 3.3 Results and discussion ........................................................................................ 33 3.3.1 Laboratory-scale studies ................................................................................. 33 3.3.2 Modeling of field studies ................................................................................ 37 3.4 Conclusion .......................................................................................................... 43 Chapter 4: Direct, non-oxidative plasma conversion of methane ..................................... 45 4.1 Introduction ........................................................................................................ 45 4.2 Methods .............................................................................................................. 45 4.2.1 Experimental ................................................................................................... 45 4.2.2 Modeling ......................................................................................................... 49 4.3 Experimental and plasma model characterization .............................................. 52 4.4 Results and discussion ........................................................................................ 59 4.4.1 Results ............................................................................................................ 59 4.4.2 Discussion ....................................................................................................... 65 II 4.5 Conclusion .......................................................................................................... 67 Chapter 5: Hydrogen gas evolution at an electrified plasma-water interface ................... 69 5.1 Introduction ........................................................................................................ 69 5.2 Methods .............................................................................................................. 69 5.3 Results and discussion ........................................................................................ 73 5.4 Conclusion .......................................................................................................... 85 Chapter 6: Continuous, process-intensified nitrogen fixation in a plasma-water droplet reactor ............................................................................................................................... 86 6.1 Introduction ........................................................................................................ 86 6.2 Methods .............................................................................................................. 86 6.3 Results and discussion ........................................................................................ 91 6.3.1 Reaction product characterization .................................................................. 91 6.3.2 Control experiments for ammonia formation ................................................. 93 6.3.3 Energy Analysis .............................................................................................. 96 6.3.4 Plasma and droplet characterization ............................................................... 98 6.3.5 Insights into reaction chemistry .................................................................... 105 6.4 Conclusions ...................................................................................................... 110 Chapter 7: Future work ................................................................................................... 111 7.1 Triboelectric charging of identical insulators ................................................... 111 7.2 Electrostatic effects on dust transport .............................................................. 111 III 7.3 Direct, non-oxidative plasma conversion of methane ...................................... 112 7.4 Hydrogen gas evolution at an electrified plasma-water interface .................... 112 7.5 Continuous, process-intensified nitrogen fixation in a plasma-water droplet reactor ......................................................................................................................... 112 References ....................................................................................................................... 114 IV List of Tables Table 5.1. Rate constants for the most favorable water vapor dissociation reactions by electron impact that produce H, presumably leading to the formation of H2 gas ..............82 V List of Figures Figure 2.1. (a) Schematic illustration and (b) 3-D illustration of the humidity chamber containing the particle fountain, the electrostatic separator, and the bins .........................16 Figure 2.2. (a) Experimentally-determined mass fraction of large particles in each sample and (b) difference between positive and negative sample large particle mass fraction as a function of chamber relative humidity ...............................................................................20 Figure 2.3. Mass fraction of particles collected in the two side bins under the electrodes as a function of applied voltage to the electrodes for a low humidity of 5 % and a high humidity of 55 % ...............................................................................................................21 Figure 2.4. Number fraction of large particles in sets that lose charge carriers and sets that gain charge carriers of the as a function of the number of collisions from a simulation of 1000 particles at the case of φΗ0= 0.015 ............................................................................23