UC Riverside UC Riverside Electronic Theses and Dissertations Title Enhancement of Membrane Filtration Process via Nanomaterial Coatings for the Generation of Electrostatic Forces, Oil Barriers, and Joule Heating Permalink https://escholarship.org/uc/item/2j776395 Author Dudchenko, Alexander Vladimirovich Publication Date 2016 Peer reviewed|Thesis/dissertation eScholarship.org Powered by the California Digital Library University of California UNIVERSITY OF CALIFORNIA RIVERSIDE Enhancement of Membrane Filtration Processes via Nanomaterial Coatings for the Generation of Electrostatic Forces, Oil Barriers, and Joule Heating A Dissertation submitted in partial satisfaction of the requirements for the degree of Doctor of Philosophy in Chemical and Environmental Engineering by Alexander Vladimirovich Dudchenko December 2016 Dissertation Committee: Dr. David Jassby, Chairperson Dr. Sharon Walker Dr. Jinyong Liu Copyright by Alexander Vladimirovich Dudchenko 2016 The Dissertation of Alexander Vladimirovich Dudchenko is approved: __________________________________________________________ __________________________________________________________ __________________________________________________________ Committee Chairperson University of California, Riverside ACKNOWLEDGMENTS I would like to thank my adviser Dr. David Jassby for his mentorship and guidance, which grew me as an individual and a professional. His sage advice, patience, and passion for research have left a great imprint on my life and will continue to have lasting influence in the future. I would like to thank Dr. Sharon Walker for her guidance during the times of my successes and counsel during times of hardship. Furthermore, I would like to thank Dr. Kurt Schwabe and Dr. Jinyong Liu for their council on my projects. I would like to especially thank Dr. Nichola Kinsinger who has mentored me throughout my time as an undergraduate and a doctorate student. Her council, mentorship, and advice have taught me how to approach research problems, develop the right questions, and inspired me to pursue work in water treatment field. I would also like to thank the undergraduate students that helped me do a lot of the hands-on work, specifically Julianne Rolf, Kyle Russell, Lucy Shi, Liana Olivas, Alexis Cardenas, Chuxiao Chen, Ryan Ward, and Hira Yoshihara-Saint. I would like to thank IGERT: Water SENSE - Water Social, Engineering, and Natural Sciences Engagement program (Award Abstract # 1144635), ACS Petroleum Research Fund (54649-DNI9), and the Office of Naval Research (N00014-14-1-0809) for funding my work. The research results discussed in this dissertation, in part or in full are reprints of three journal articles. The first article is reprinted from Journal of Membrane Science, volume 468, by A.V. Dudchenko, J. Rolf, K. Russle, W. Duan, and D. Jassby, “Organic Fouling Inhibition on Electrically Conducting Carbon Nanotube – Polyvinyl Alcohol iv Composite Ultrafiltration Membranes”, pages 1-10, Copyright © 2014, with permission from Elsevier B.V. The second article is reprinted with permission from ACS Nano, volume 9, issue 10, entitled “Coupling Underwater Superoleophobic Membranes with Magnetic Pickering Emulsions for Fouling-Free Separation of Crude Oil/Water Mixtures: An Experimental and Theoretical Study”, by A.V. Dudchenko, J. Rolf, L. Shi, L. Olivas, W. Duan, and D.Jassby Copyright © 2014 American Chemical Society. The third article is under current review in Nature Nanotechnology, entitled “Frequency Dependent Stability of CNT Joule Heaters in Ionizable Environments: Implications for Desalination”, by A.V. Dudchenko, C. Chen, A. Cardenas, J. Rolf, and D. Jassby, upon acceptance all rights will belong to the appropriate publisher. In these publications, co-authors Julianne Rolf, Kyle Russell, Lucy Shi, Liana Olivas, Alexis Cardenas, Chuxiao Chen, and Wenyan Duan assisted in preparation, and characterization of materials used to complete the experimental work. The co-author Dr. David Jassby directed and supervised the research in these publications, which have greatly improved their quality and depth. v DEDICATIONS This dissertation is dedicated to my mother and my fiancé, as well as the rest of my family who supported me since childhood, and without whom I could not have pursued my dreams. vi ABSTRACT OF THE DISSERTATION Enhancement of Membrane Filtration Processes via Nanomaterial Coatings for the Generation of Electrostatic Forces, Oil Barriers, and Joule Heating by Alexander Vladimirovich Dudchenko Doctor of Philosophy, Graduate Program in Chemical and Environmental Engineering University of California, Riverside, December 2016 Dr. David Jassby, Chairperson Water scarcity exasperated by global climate change and growing population is a growing challenge for many regions of the world. The water shortages are prompting regions to look for new water sources to supplement their dwindling water supplies ranging from wastewater reuse to saline ground water desalination. Membrane filtration is one of the few technologies that can treat these water sources but suffers from fouling, and complicated system designs. Herein we present methods to address problems faced by membrane filtration through use of nanomaterial-based thin films that actively address key problems faced by membrane filtration processes. Organic contaminants commonly found in surface water, ground water, and wastewater rapidly foul membranes, leading to decline in their performance. We demonstrate that application of electrical potentials to electrically conductive and robust carbon nanotube (CNT) thin films deposited on UF membranes allows for generation of vii strong electrostatic repulsive forces. We demonstrate that these artificially generated electrostatic forces can reduces membrane fouling during treatment of synthetic wastewaters and model organic foulants, with the results being qualitatively explained by the solution of modified Poisson-Boltzmann equation. Although our results demonstrate electrostatics forces are effective at preventing organic fouling, their efficacy suffers in saline waters such as produced, flow back, and industrial waste waters. These waters can contain oil emulsions made up of small and stable oil droplets that can rapidly foul membranes. We take advantage of the nano-magnetite properties, which cause the nano- particles to form a film at the water-oil interphase. The nano-magnetite films create a physical barrier that prevents oil droplets from interacting with the membrane surface or coalesce during filtration. The fouling prevention is explored as a function of nano-particle and membrane hydrophilicity with a developed theoretical framework qualitatively explaining our experimental results. Finally, we demonstrate that the previously prepared CNT films when deposited on hydrophobic membranes can be used to drive membrane distillation (MD) process via Joule heating effect. We explore the stability of the CNT films using electrical impedance spectroscopy (EIS) under different frequencies and salinities and demonstrate that they can be used to achieve exceptionally high single pass recoveries in MD. viii Table of Contents Introduction ................................................................................................... 1 1.1 Water Scarcity ...................................................................................................... 2 1.1.1 A Brief History of Membrane Filtration ....................................................... 3 1.2 Fundamentals of Membrane Filtration ................................................................. 5 1.2.1 Membrane Rejection Mechanisms ................................................................ 5 1.2.2 Synthesis and Morphology of Filtration Membranes ................................... 7 1.2.3 The Driving Force in Membrane Filtration, and Operational Modes ......... 15 1.3 Forces in Membrane Filtration, from Drag to DLVO and Beyond .................... 19 1.3.1 Fluid Drag Forces ....................................................................................... 20 1.3.2 The Classical DLVO ................................................................................... 21 1.3.3 The Hydration and Hydrophobic Forces..................................................... 23 1.3.4 The Steric Forces ........................................................................................ 25 1.4 Fouling in Membrane Filtration ......................................................................... 25 1.4.1 Pore Blocking and Constriction .................................................................. 26 1.4.2 Cake Layer Formation ................................................................................ 27 1.4.3 Gel Layer Formation, Macromolecules and Ion Bridging .......................... 29 1.5 Fouling Prevention of Organic Molecules Using Hydrophilicity and Surface Charge ........................................................................................................................... 30 ix 1.6 Electrokinetic Fouling Prevention ...................................................................... 32 1.7 Treatment of Oil Emulsions ............................................................................... 34 1.8 Treatment of Saline Brines with Membrane Distillation ................................... 41 1.8.1 Membrane Distillation Operation ............................................................... 41 1.8.2 Membrane Distillation Challenges ............................................................