ingest cdrApp 2017-07-06T12:35:02.927Z ccd64451-f0fc-4a42-94ad-226f4041fa4f modifyDatastreamByValue RELS-EXT fedoraAdmin 2017-07-06T13:14:05.409Z Setting exclusive relation modifyDatastreamByValue RELS-EXT fedoraAdmin 2017-07-06T13:14:13.659Z Setting exclusive relation addDatastream MD_TECHNICAL fedoraAdmin 2017-07-06T13:14:21.712Z Adding technical metadata derived by FITS modifyDatastreamByValue RELS-EXT fedoraAdmin 2017-07-06T13:14:37.720Z Setting exclusive relation addDatastream MD_FULL_TEXT fedoraAdmin 2017-07-06T13:14:48.133Z Adding full text metadata extracted by Apache Tika modifyDatastreamByValue RELS-EXT fedoraAdmin 2017-07-06T13:15:04.753Z Setting exclusive relation modifyDatastreamByValue RELS-EXT cdrApp 2017-07-06T13:19:26.647Z Setting exclusive relation modifyDatastreamByValue MD_DESCRIPTIVE cdrApp 2017-09-29T18:18:39.121Z modifyDatastreamByValue MD_DESCRIPTIVE cdrApp 2018-01-25T12:07:03.154Z modifyDatastreamByValue MD_DESCRIPTIVE cdrApp 2018-01-27T12:11:15.021Z modifyDatastreamByValue MD_DESCRIPTIVE cdrApp 2018-02-28T19:28:15.225Z modifyDatastreamByValue MD_DESCRIPTIVE cdrApp 2018-03-14T09:21:26.603Z modifyDatastreamByValue MD_DESCRIPTIVE cdrApp 2018-05-17T20:51:48.667Z modifyDatastreamByValue MD_DESCRIPTIVE cdrApp 2018-07-11T07:48:07.459Z modifyDatastreamByValue MD_DESCRIPTIVE cdrApp 2018-07-18T03:57:54.912Z modifyDatastreamByValue MD_DESCRIPTIVE cdrApp 2018-08-16T17:06:04.701Z modifyDatastreamByValue MD_DESCRIPTIVE cdrApp 2018-09-27T12:48:27.519Z modifyDatastreamByValue MD_DESCRIPTIVE cdrApp 2018-10-12T04:05:45.476Z modifyDatastreamByValue MD_DESCRIPTIVE cdrApp 2019-03-21T13:43:07.575Z Lamar Perry Author Materials Science Program UNDERSTANDING THE PROPERTY-PERFORMANCE RELATIONSHIPS OF MEMBRANE ACTIVE LAYERS CONTAINING POROUS NANOPARTICLES ABSTRACT Lamar (Tony) Perry: Understanding the Property-Performance Relationships Of Membrane Active Layers Containing Porous Nanoparticles (Under the direction of Orlando Coronell) Thin-film nanocomposite (TFN) membranes for water purification have emerged in the last decade as a class of membranes that can provide increased water productivity over traditional thin-film composite (TFC) membranes, but still maintain the same level of contaminant rejection. The mechanisms by which the increased water permeability is achieved are not well understood as there are no comprehensive studies on the relevant structure-performance relationships. Accordingly, the overall objective of this study was to advance the understanding of the property-performance relationships of TFN membranes containing porous nanoparticles in their active layers. Towards achieving my overall objective, I pursued the following specific objectives: (i) to develop a method to measure charge density in active layers of polyamide-based TFC and TFN membranes; (ii) to characterize the effect of LTA zeolite loading on the physico-chemical properties of the active layers of zeolite TFN membranes, and investigate their corresponding structure-performance relationships; and (iii) to characterize the effect of ZIF8 nanoparticle loading, surface area, and size on the performance of ZIF8-TFN membranes, and investigate their corresponding structure-performance relationships. Overall, the results obtained in this study showed that zeolite and ZIF8 nanoparticle incorporation into active layers results in higher water productivity, and unchanged salt rejection up to a zeolite loading threshold above which salt rejection decreases (~0.15 wt% in the organic TMC solution used to cast the active layer). Results and analyses also showed that the observed changes in the physico-chemical properties of the active layer polymer did not explain the observed changes in membrane performance. Therefore, it is concluded that the increased water productivity of TFN membranes over the control TFC membranes is the result of water transport through the porous structure of LTA zeolite and ZIF8 nanoparticles, or along the polymer-nanoparticle interface. Alternatively, nanoparticle incorporation may have changed properties of the active layer polymer not characterized in this study (i.e., water diffusivity, or microstructure) in such a way such that it led to greater water permeability. Spring 2017 2017 Environmental science Membrane active layers, Membrane charge, Physico-chemical properties, Porous nanoparticles, Reverse osmosis, ZIF8 nanoparticles eng Doctor of Philosophy Dissertation University of North Carolina at Chapel Hill Graduate School Degree granting institution Materials Science Orlando Coronell Thesis advisor Mary Laura Lind Thesis advisor Richard Superfine Thesis advisor Rene Lopez Thesis advisor Wei You Thesis advisor text Lamar Perry Author Materials Science Program Department of Applied Physical Sciences College of Arts and Sciences UNDERSTANDING THE PROPERTY-PERFORMANCE RELATIONSHIPS OF MEMBRANE ACTIVE LAYERS CONTAINING POROUS NANOPARTICLES Thin-film nanocomposite (TFN) membranes for water purification have emerged in the last decade as a class of membranes that can provide increased water productivity over traditional thin-film composite (TFC) membranes, but still maintain the same level of contaminant rejection. The mechanisms by which the increased water permeability is achieved are not well understood as there are no comprehensive studies on the relevant structure-performance relationships. Accordingly, the overall objective of this study was to advance the understanding of the property-performance relationships of TFN membranes containing porous nanoparticles in their active layers. Towards achieving my overall objective, I pursued the following specific objectives: (i) to develop a method to measure charge density in active layers of polyamide-based TFC and TFN membranes; (ii) to characterize the effect of LTA zeolite loading on the physico-chemical properties of the active layers of zeolite TFN membranes, and investigate their corresponding structure-performance relationships; and (iii) to characterize the effect of ZIF8 nanoparticle loading, surface area, and size on the performance of ZIF8-TFN membranes, and investigate their corresponding structure-performance relationships. Overall, the results obtained in this study showed that zeolite and ZIF8 nanoparticle incorporation into active layers results in higher water productivity, and unchanged salt rejection up to a zeolite loading threshold above which salt rejection decreases (~0.15 wt% in the organic TMC solution used to cast the active layer). Results and analyses also showed that the observed changes in the physico-chemical properties of the active layer polymer did not explain the observed changes in membrane performance. Therefore, it is concluded that the increased water productivity of TFN membranes over the control TFC membranes is the result of water transport through the porous structure of LTA zeolite and ZIF8 nanoparticles, or along the polymer-nanoparticle interface. Alternatively, nanoparticle incorporation may have changed properties of the active layer polymer not characterized in this study (i.e., water diffusivity, or microstructure) in such a way such that it led to greater water permeability. Spring 2017 2017 Environmental science Membrane active layers, Membrane charge, Physico-chemical properties, Porous nanoparticles, Reverse osmosis, ZIF8 nanoparticles eng Doctor of Philosophy Dissertation University of North Carolina at Chapel Hill Graduate School Degree granting institution Materials Science Orlando Coronell Thesis advisor Mary Laura Lind Thesis advisor Richard Superfine Thesis advisor Rene Lopez Thesis advisor Wei You Thesis advisor text Lamar Perry Creator Materials Science Program Department of Applied Physical Sciences College of Arts and Sciences UNDERSTANDING THE PROPERTY-PERFORMANCE RELATIONSHIPS OF MEMBRANE ACTIVE LAYERS CONTAINING POROUS NANOPARTICLES Thin-film nanocomposite (TFN) membranes for water purification have emerged in the last decade as a class of membranes that can provide increased water productivity over traditional thin-film composite (TFC) membranes, but still maintain the same level of contaminant rejection. The mechanisms by which the increased water permeability is achieved are not well understood as there are no comprehensive studies on the relevant structure-performance relationships. Accordingly, the overall objective of this study was to advance the understanding of the property-performance relationships of TFN membranes containing porous nanoparticles in their active layers. Towards achieving my overall objective, I pursued the following specific objectives: (i) to develop a method to measure charge density in active layers of polyamide-based TFC and TFN membranes; (ii) to characterize the effect of LTA zeolite loading on the physico-chemical properties of the active layers of zeolite TFN membranes, and investigate their corresponding structure-performance relationships; and (iii) to characterize the effect of ZIF8 nanoparticle loading, surface area, and size on the performance of ZIF8-TFN membranes, and investigate their corresponding structure-performance relationships. Overall, the results obtained in this study showed that zeolite and ZIF8 nanoparticle incorporation into active layers results in higher water productivity, and unchanged salt rejection up to a zeolite loading threshold above which salt rejection decreases (~0.15 wt% in the organic TMC solution used to cast the active layer). Results and analyses also showed that the observed changes in the physico-chemical properties of the active layer polymer did not explain the observed changes in membrane performance. Therefore, it is concluded that the increased water productivity of TFN membranes over the control TFC membranes is the result of water transport through the porous structure of LTA zeolite and ZIF8 nanoparticles, or along the polymer-nanoparticle interface. Alternatively, nanoparticle incorporation may have changed properties of the active layer polymer not characterized in this study (i.e., water diffusivity, or microstructure) in such a way such that it led to greater water permeability. Spring 2017 2017 Environmental science Membrane active layers, Membrane charge, Physico-chemical properties, Porous nanoparticles, Reverse osmosis, ZIF8 nanoparticles eng Doctor of Philosophy Dissertation University of North Carolina at Chapel Hill Graduate School Degree granting institution Materials Science Orlando Coronell Thesis advisor Mary Laura Lind Thesis advisor Richard Superfine Thesis advisor Rene Lopez Thesis advisor Wei You Thesis advisor text Lamar Perry Creator Materials Science Program Department of Applied Physical Sciences College of Arts and Sciences UNDERSTANDING THE PROPERTY-PERFORMANCE RELATIONSHIPS OF MEMBRANE ACTIVE LAYERS CONTAINING POROUS NANOPARTICLES Thin-film nanocomposite (TFN) membranes for water purification have emerged in the last decade as a class of membranes that can provide increased water productivity over traditional thin-film composite (TFC) membranes, but still maintain the same level of contaminant rejection. The mechanisms by which the increased water permeability is achieved are not well understood as there are no comprehensive studies on the relevant structure-performance relationships. Accordingly, the overall objective of this study was to advance the understanding of the property-performance relationships of TFN membranes containing porous nanoparticles in their active layers. Towards achieving my overall objective, I pursued the following specific objectives: (i) to develop a method to measure charge density in active layers of polyamide-based TFC and TFN membranes; (ii) to characterize the effect of LTA zeolite loading on the physico-chemical properties of the active layers of zeolite TFN membranes, and investigate their corresponding structure-performance relationships; and (iii) to characterize the effect of ZIF8 nanoparticle loading, surface area, and size on the performance of ZIF8-TFN membranes, and investigate their corresponding structure-performance relationships. Overall, the results obtained in this study showed that zeolite and ZIF8 nanoparticle incorporation into active layers results in higher water productivity, and unchanged salt rejection up to a zeolite loading threshold above which salt rejection decreases (~0.15 wt% in the organic TMC solution used to cast the active layer). Results and analyses also showed that the observed changes in the physico-chemical properties of the active layer polymer did not explain the observed changes in membrane performance. Therefore, it is concluded that the increased water productivity of TFN membranes over the control TFC membranes is the result of water transport through the porous structure of LTA zeolite and ZIF8 nanoparticles, or along the polymer-nanoparticle interface. Alternatively, nanoparticle incorporation may have changed properties of the active layer polymer not characterized in this study (i.e., water diffusivity, or microstructure) in such a way such that it led to greater water permeability. Spring 2017 2017 Environmental science Membrane active layers, Membrane charge, Physico-chemical properties, Porous nanoparticles, Reverse osmosis, ZIF8 nanoparticles eng Doctor of Philosophy Dissertation University of North Carolina at Chapel Hill Graduate School Degree granting institution Materials Science Orlando Coronell Thesis advisor Mary Laura Lind Thesis advisor Richard Superfine Thesis advisor Rene Lopez Thesis advisor Wei You Thesis advisor text Lamar Perry Creator Materials Science Graduate Program Department of Applied Physical Sciences College of Arts and Sciences UNDERSTANDING THE PROPERTY-PERFORMANCE RELATIONSHIPS OF MEMBRANE ACTIVE LAYERS CONTAINING POROUS NANOPARTICLES Thin-film nanocomposite (TFN) membranes for water purification have emerged in the last decade as a class of membranes that can provide increased water productivity over traditional thin-film composite (TFC) membranes, but still maintain the same level of contaminant rejection. The mechanisms by which the increased water permeability is achieved are not well understood as there are no comprehensive studies on the relevant structure-performance relationships. Accordingly, the overall objective of this study was to advance the understanding of the property-performance relationships of TFN membranes containing porous nanoparticles in their active layers. Towards achieving my overall objective, I pursued the following specific objectives: (i) to develop a method to measure charge density in active layers of polyamide-based TFC and TFN membranes; (ii) to characterize the effect of LTA zeolite loading on the physico-chemical properties of the active layers of zeolite TFN membranes, and investigate their corresponding structure-performance relationships; and (iii) to characterize the effect of ZIF8 nanoparticle loading, surface area, and size on the performance of ZIF8-TFN membranes, and investigate their corresponding structure-performance relationships. Overall, the results obtained in this study showed that zeolite and ZIF8 nanoparticle incorporation into active layers results in higher water productivity, and unchanged salt rejection up to a zeolite loading threshold above which salt rejection decreases (~0.15 wt% in the organic TMC solution used to cast the active layer). Results and analyses also showed that the observed changes in the physico-chemical properties of the active layer polymer did not explain the observed changes in membrane performance. Therefore, it is concluded that the increased water productivity of TFN membranes over the control TFC membranes is the result of water transport through the porous structure of LTA zeolite and ZIF8 nanoparticles, or along the polymer-nanoparticle interface. Alternatively, nanoparticle incorporation may have changed properties of the active layer polymer not characterized in this study (i.e., water diffusivity, or microstructure) in such a way such that it led to greater water permeability. Spring 2017 2017 Environmental science Membrane active layers, Membrane charge, Physico-chemical properties, Porous nanoparticles, Reverse osmosis, ZIF8 nanoparticles eng Doctor of Philosophy Dissertation University of North Carolina at Chapel Hill Graduate School Degree granting institution Materials Science Orlando Coronell Thesis advisor Mary Laura Lind Thesis advisor Richard Superfine Thesis advisor Rene Lopez Thesis advisor Wei You Thesis advisor text Lamar Perry Creator Materials Science Graduate Program Department of Applied Physical Sciences College of Arts and Sciences UNDERSTANDING THE PROPERTY-PERFORMANCE RELATIONSHIPS OF MEMBRANE ACTIVE LAYERS CONTAINING POROUS NANOPARTICLES Thin-film nanocomposite (TFN) membranes for water purification have emerged in the last decade as a class of membranes that can provide increased water productivity over traditional thin-film composite (TFC) membranes, but still maintain the same level of contaminant rejection. The mechanisms by which the increased water permeability is achieved are not well understood as there are no comprehensive studies on the relevant structure-performance relationships. Accordingly, the overall objective of this study was to advance the understanding of the property-performance relationships of TFN membranes containing porous nanoparticles in their active layers. Towards achieving my overall objective, I pursued the following specific objectives: (i) to develop a method to measure charge density in active layers of polyamide-based TFC and TFN membranes; (ii) to characterize the effect of LTA zeolite loading on the physico-chemical properties of the active layers of zeolite TFN membranes, and investigate their corresponding structure-performance relationships; and (iii) to characterize the effect of ZIF8 nanoparticle loading, surface area, and size on the performance of ZIF8-TFN membranes, and investigate their corresponding structure-performance relationships. Overall, the results obtained in this study showed that zeolite and ZIF8 nanoparticle incorporation into active layers results in higher water productivity, and unchanged salt rejection up to a zeolite loading threshold above which salt rejection decreases (~0.15 wt% in the organic TMC solution used to cast the active layer). Results and analyses also showed that the observed changes in the physico-chemical properties of the active layer polymer did not explain the observed changes in membrane performance. Therefore, it is concluded that the increased water productivity of TFN membranes over the control TFC membranes is the result of water transport through the porous structure of LTA zeolite and ZIF8 nanoparticles, or along the polymer-nanoparticle interface. Alternatively, nanoparticle incorporation may have changed properties of the active layer polymer not characterized in this study (i.e., water diffusivity, or microstructure) in such a way such that it led to greater water permeability. 2017-05 2017 Environmental science Membrane active layers, Membrane charge, Physico-chemical properties, Porous nanoparticles, Reverse osmosis, ZIF8 nanoparticles eng Doctor of Philosophy Dissertation University of North Carolina at Chapel Hill Graduate School Degree granting institution Materials Science Orlando Coronell Thesis advisor Mary Laura Lind Thesis advisor Richard Superfine Thesis advisor Rene Lopez Thesis advisor Wei You Thesis advisor text Lamar Perry Creator Materials Science Graduate Program Department of Applied Physical Sciences College of Arts and Sciences UNDERSTANDING THE PROPERTY-PERFORMANCE RELATIONSHIPS OF MEMBRANE ACTIVE LAYERS CONTAINING POROUS NANOPARTICLES Thin-film nanocomposite (TFN) membranes for water purification have emerged in the last decade as a class of membranes that can provide increased water productivity over traditional thin-film composite (TFC) membranes, but still maintain the same level of contaminant rejection. The mechanisms by which the increased water permeability is achieved are not well understood as there are no comprehensive studies on the relevant structure-performance relationships. Accordingly, the overall objective of this study was to advance the understanding of the property-performance relationships of TFN membranes containing porous nanoparticles in their active layers. Towards achieving my overall objective, I pursued the following specific objectives: (i) to develop a method to measure charge density in active layers of polyamide-based TFC and TFN membranes; (ii) to characterize the effect of LTA zeolite loading on the physico-chemical properties of the active layers of zeolite TFN membranes, and investigate their corresponding structure-performance relationships; and (iii) to characterize the effect of ZIF8 nanoparticle loading, surface area, and size on the performance of ZIF8-TFN membranes, and investigate their corresponding structure-performance relationships. Overall, the results obtained in this study showed that zeolite and ZIF8 nanoparticle incorporation into active layers results in higher water productivity, and unchanged salt rejection up to a zeolite loading threshold above which salt rejection decreases (~0.15 wt% in the organic TMC solution used to cast the active layer). Results and analyses also showed that the observed changes in the physico-chemical properties of the active layer polymer did not explain the observed changes in membrane performance. Therefore, it is concluded that the increased water productivity of TFN membranes over the control TFC membranes is the result of water transport through the porous structure of LTA zeolite and ZIF8 nanoparticles, or along the polymer-nanoparticle interface. Alternatively, nanoparticle incorporation may have changed properties of the active layer polymer not characterized in this study (i.e., water diffusivity, or microstructure) in such a way such that it led to greater water permeability. 2017 Environmental science Membrane active layers, Membrane charge, Physico-chemical properties, Porous nanoparticles, Reverse osmosis, ZIF8 nanoparticles eng Doctor of Philosophy Dissertation University of North Carolina at Chapel Hill Graduate School Degree granting institution Materials Science Orlando Coronell Thesis advisor Mary Laura Lind Thesis advisor Richard Superfine Thesis advisor Rene Lopez Thesis advisor Wei You Thesis advisor text 2017-05 Lamar Perry Creator Materials Science Graduate Program Department of Applied Physical Sciences College of Arts and Sciences UNDERSTANDING THE PROPERTY-PERFORMANCE RELATIONSHIPS OF MEMBRANE ACTIVE LAYERS CONTAINING POROUS NANOPARTICLES Thin-film nanocomposite (TFN) membranes for water purification have emerged in the last decade as a class of membranes that can provide increased water productivity over traditional thin-film composite (TFC) membranes, but still maintain the same level of contaminant rejection. The mechanisms by which the increased water permeability is achieved are not well understood as there are no comprehensive studies on the relevant structure-performance relationships. Accordingly, the overall objective of this study was to advance the understanding of the property-performance relationships of TFN membranes containing porous nanoparticles in their active layers. Towards achieving my overall objective, I pursued the following specific objectives: (i) to develop a method to measure charge density in active layers of polyamide-based TFC and TFN membranes; (ii) to characterize the effect of LTA zeolite loading on the physico-chemical properties of the active layers of zeolite TFN membranes, and investigate their corresponding structure-performance relationships; and (iii) to characterize the effect of ZIF8 nanoparticle loading, surface area, and size on the performance of ZIF8-TFN membranes, and investigate their corresponding structure-performance relationships. Overall, the results obtained in this study showed that zeolite and ZIF8 nanoparticle incorporation into active layers results in higher water productivity, and unchanged salt rejection up to a zeolite loading threshold above which salt rejection decreases (~0.15 wt% in the organic TMC solution used to cast the active layer). Results and analyses also showed that the observed changes in the physico-chemical properties of the active layer polymer did not explain the observed changes in membrane performance. Therefore, it is concluded that the increased water productivity of TFN membranes over the control TFC membranes is the result of water transport through the porous structure of LTA zeolite and ZIF8 nanoparticles, or along the polymer-nanoparticle interface. Alternatively, nanoparticle incorporation may have changed properties of the active layer polymer not characterized in this study (i.e., water diffusivity, or microstructure) in such a way such that it led to greater water permeability. 2017 Environmental science Membrane active layers, Membrane charge, Physico-chemical properties, Porous nanoparticles, Reverse osmosis, ZIF8 nanoparticles eng Doctor of Philosophy Dissertation University of North Carolina at Chapel Hill Graduate School Degree granting institution Materials Science Orlando Coronell Thesis advisor Mary Laura Lind Thesis advisor Richard Superfine Thesis advisor Rene Lopez Thesis advisor Wei You Thesis advisor text 2017-05 Lamar Perry Creator Materials Science Graduate Program Department of Applied Physical Sciences College of Arts and Sciences UNDERSTANDING THE PROPERTY-PERFORMANCE RELATIONSHIPS OF MEMBRANE ACTIVE LAYERS CONTAINING POROUS NANOPARTICLES Thin-film nanocomposite (TFN) membranes for water purification have emerged in the last decade as a class of membranes that can provide increased water productivity over traditional thin-film composite (TFC) membranes, but still maintain the same level of contaminant rejection. The mechanisms by which the increased water permeability is achieved are not well understood as there are no comprehensive studies on the relevant structure-performance relationships. Accordingly, the overall objective of this study was to advance the understanding of the property-performance relationships of TFN membranes containing porous nanoparticles in their active layers. Towards achieving my overall objective, I pursued the following specific objectives: (i) to develop a method to measure charge density in active layers of polyamide-based TFC and TFN membranes; (ii) to characterize the effect of LTA zeolite loading on the physico-chemical properties of the active layers of zeolite TFN membranes, and investigate their corresponding structure-performance relationships; and (iii) to characterize the effect of ZIF8 nanoparticle loading, surface area, and size on the performance of ZIF8-TFN membranes, and investigate their corresponding structure-performance relationships. Overall, the results obtained in this study showed that zeolite and ZIF8 nanoparticle incorporation into active layers results in higher water productivity, and unchanged salt rejection up to a zeolite loading threshold above which salt rejection decreases (~0.15 wt% in the organic TMC solution used to cast the active layer). Results and analyses also showed that the observed changes in the physico-chemical properties of the active layer polymer did not explain the observed changes in membrane performance. Therefore, it is concluded that the increased water productivity of TFN membranes over the control TFC membranes is the result of water transport through the porous structure of LTA zeolite and ZIF8 nanoparticles, or along the polymer-nanoparticle interface. Alternatively, nanoparticle incorporation may have changed properties of the active layer polymer not characterized in this study (i.e., water diffusivity, or microstructure) in such a way such that it led to greater water permeability. 2017 Environmental science Membrane active layers, Membrane charge, Physico-chemical properties, Porous nanoparticles, Reverse osmosis, ZIF8 nanoparticles eng Doctor of Philosophy Dissertation University of North Carolina at Chapel Hill Graduate School Degree granting institution Materials Science Orlando Coronell Thesis advisor Mary Laura Lind Thesis advisor Richard Superfine Thesis advisor Rene Lopez Thesis advisor Wei You Thesis advisor text 2017-05 Lamar Perry Creator Materials Science Graduate Program Department of Applied Physical Sciences College of Arts and Sciences UNDERSTANDING THE PROPERTY-PERFORMANCE RELATIONSHIPS OF MEMBRANE ACTIVE LAYERS CONTAINING POROUS NANOPARTICLES Thin-film nanocomposite (TFN) membranes for water purification have emerged in the last decade as a class of membranes that can provide increased water productivity over traditional thin-film composite (TFC) membranes, but still maintain the same level of contaminant rejection. The mechanisms by which the increased water permeability is achieved are not well understood as there are no comprehensive studies on the relevant structure-performance relationships. Accordingly, the overall objective of this study was to advance the understanding of the property-performance relationships of TFN membranes containing porous nanoparticles in their active layers. Towards achieving my overall objective, I pursued the following specific objectives: (i) to develop a method to measure charge density in active layers of polyamide-based TFC and TFN membranes; (ii) to characterize the effect of LTA zeolite loading on the physico-chemical properties of the active layers of zeolite TFN membranes, and investigate their corresponding structure-performance relationships; and (iii) to characterize the effect of ZIF8 nanoparticle loading, surface area, and size on the performance of ZIF8-TFN membranes, and investigate their corresponding structure-performance relationships. Overall, the results obtained in this study showed that zeolite and ZIF8 nanoparticle incorporation into active layers results in higher water productivity, and unchanged salt rejection up to a zeolite loading threshold above which salt rejection decreases (~0.15 wt% in the organic TMC solution used to cast the active layer). Results and analyses also showed that the observed changes in the physico-chemical properties of the active layer polymer did not explain the observed changes in membrane performance. Therefore, it is concluded that the increased water productivity of TFN membranes over the control TFC membranes is the result of water transport through the porous structure of LTA zeolite and ZIF8 nanoparticles, or along the polymer-nanoparticle interface. Alternatively, nanoparticle incorporation may have changed properties of the active layer polymer not characterized in this study (i.e., water diffusivity, or microstructure) in such a way such that it led to greater water permeability. 2017 Environmental science Membrane active layers, Membrane charge, Physico-chemical properties, Porous nanoparticles, Reverse osmosis, ZIF8 nanoparticles eng Doctor of Philosophy Dissertation Materials Science Orlando Coronell Thesis advisor Mary Laura Lind Thesis advisor Richard Superfine Thesis advisor Rene Lopez Thesis advisor Wei You Thesis advisor text 2017-05 University of North Carolina at Chapel Hill Degree granting institution Lamar Perry Creator Materials Science Graduate Program Department of Applied Physical Sciences College of Arts and Sciences UNDERSTANDING THE PROPERTY-PERFORMANCE RELATIONSHIPS OF MEMBRANE ACTIVE LAYERS CONTAINING POROUS NANOPARTICLES Thin-film nanocomposite (TFN) membranes for water purification have emerged in the last decade as a class of membranes that can provide increased water productivity over traditional thin-film composite (TFC) membranes, but still maintain the same level of contaminant rejection. The mechanisms by which the increased water permeability is achieved are not well understood as there are no comprehensive studies on the relevant structure-performance relationships. Accordingly, the overall objective of this study was to advance the understanding of the property-performance relationships of TFN membranes containing porous nanoparticles in their active layers. Towards achieving my overall objective, I pursued the following specific objectives: (i) to develop a method to measure charge density in active layers of polyamide-based TFC and TFN membranes; (ii) to characterize the effect of LTA zeolite loading on the physico-chemical properties of the active layers of zeolite TFN membranes, and investigate their corresponding structure-performance relationships; and (iii) to characterize the effect of ZIF8 nanoparticle loading, surface area, and size on the performance of ZIF8-TFN membranes, and investigate their corresponding structure-performance relationships. Overall, the results obtained in this study showed that zeolite and ZIF8 nanoparticle incorporation into active layers results in higher water productivity, and unchanged salt rejection up to a zeolite loading threshold above which salt rejection decreases (~0.15 wt% in the organic TMC solution used to cast the active layer). Results and analyses also showed that the observed changes in the physico-chemical properties of the active layer polymer did not explain the observed changes in membrane performance. Therefore, it is concluded that the increased water productivity of TFN membranes over the control TFC membranes is the result of water transport through the porous structure of LTA zeolite and ZIF8 nanoparticles, or along the polymer-nanoparticle interface. Alternatively, nanoparticle incorporation may have changed properties of the active layer polymer not characterized in this study (i.e., water diffusivity, or microstructure) in such a way such that it led to greater water permeability. 2017 Environmental science Membrane active layers; Membrane charge; Physico-chemical properties; Porous nanoparticles; Reverse osmosis; ZIF8 nanoparticles eng Doctor of Philosophy Dissertation Materials Science Orlando Coronell Thesis advisor Mary Laura Lind Thesis advisor Richard Superfine Thesis advisor Rene Lopez Thesis advisor Wei You Thesis advisor text 2017-05 University of North Carolina at Chapel Hill Degree granting institution Lamar Perry Creator Materials Science Graduate Program Department of Applied Physical Sciences College of Arts and Sciences UNDERSTANDING THE PROPERTY-PERFORMANCE RELATIONSHIPS OF MEMBRANE ACTIVE LAYERS CONTAINING POROUS NANOPARTICLES Thin-film nanocomposite (TFN) membranes for water purification have emerged in the last decade as a class of membranes that can provide increased water productivity over traditional thin-film composite (TFC) membranes, but still maintain the same level of contaminant rejection. The mechanisms by which the increased water permeability is achieved are not well understood as there are no comprehensive studies on the relevant structure-performance relationships. Accordingly, the overall objective of this study was to advance the understanding of the property-performance relationships of TFN membranes containing porous nanoparticles in their active layers. Towards achieving my overall objective, I pursued the following specific objectives: (i) to develop a method to measure charge density in active layers of polyamide-based TFC and TFN membranes; (ii) to characterize the effect of LTA zeolite loading on the physico-chemical properties of the active layers of zeolite TFN membranes, and investigate their corresponding structure-performance relationships; and (iii) to characterize the effect of ZIF8 nanoparticle loading, surface area, and size on the performance of ZIF8-TFN membranes, and investigate their corresponding structure-performance relationships. Overall, the results obtained in this study showed that zeolite and ZIF8 nanoparticle incorporation into active layers results in higher water productivity, and unchanged salt rejection up to a zeolite loading threshold above which salt rejection decreases (~0.15 wt% in the organic TMC solution used to cast the active layer). Results and analyses also showed that the observed changes in the physico-chemical properties of the active layer polymer did not explain the observed changes in membrane performance. Therefore, it is concluded that the increased water productivity of TFN membranes over the control TFC membranes is the result of water transport through the porous structure of LTA zeolite and ZIF8 nanoparticles, or along the polymer-nanoparticle interface. Alternatively, nanoparticle incorporation may have changed properties of the active layer polymer not characterized in this study (i.e., water diffusivity, or microstructure) in such a way such that it led to greater water permeability. 2017 Environmental science Membrane active layers, Membrane charge, Physico-chemical properties, Porous nanoparticles, Reverse osmosis, ZIF8 nanoparticles eng Doctor of Philosophy Dissertation University of North Carolina at Chapel Hill Graduate School Degree granting institution Materials Science Orlando Coronell Thesis advisor Mary Laura Lind Thesis advisor Richard Superfine Thesis advisor Rene Lopez Thesis advisor Wei You Thesis advisor text 2017-05 Lamar Perry Creator Materials Science Graduate Program Department of Applied Physical Sciences College of Arts and Sciences Thin-film nanocomposite (TFN) membranes for water purification have emerged in the last decade as a class of membranes that can provide increased water productivity over traditional thin-film composite (TFC) membranes, but still maintain the same level of contaminant rejection. The mechanisms by which the increased water permeability is achieved are not well understood as there are no comprehensive studies on the relevant structure-performance relationships. Accordingly, the overall objective of this study was to advance the understanding of the property-performance relationships of TFN membranes containing porous nanoparticles in their active layers. Towards achieving my overall objective, I pursued the following specific objectives: (i) to develop a method to measure charge density in active layers of polyamide-based TFC and TFN membranes; (ii) to characterize the effect of LTA zeolite loading on the physico-chemical properties of the active layers of zeolite TFN membranes, and investigate their corresponding structure-performance relationships; and (iii) to characterize the effect of ZIF8 nanoparticle loading, surface area, and size on the performance of ZIF8-TFN membranes, and investigate their corresponding structure-performance relationships. Overall, the results obtained in this study showed that zeolite and ZIF8 nanoparticle incorporation into active layers results in higher water productivity, and unchanged salt rejection up to a zeolite loading threshold above which salt rejection decreases (~0.15 wt% in the organic TMC solution used to cast the active layer). Results and analyses also showed that the observed changes in the physico-chemical properties of the active layer polymer did not explain the observed changes in membrane performance. Therefore, it is concluded that the increased water productivity of TFN membranes over the control TFC membranes is the result of water transport through the porous structure of LTA zeolite and ZIF8 nanoparticles, or along the polymer-nanoparticle interface. Alternatively, nanoparticle incorporation may have changed properties of the active layer polymer not characterized in this study (i.e., water diffusivity, or microstructure) in such a way such that it led to greater water permeability. 2017 Environmental science Membrane active layers; Membrane charge; Physico-chemical properties; Porous nanoparticles; Reverse osmosis; ZIF8 nanoparticles eng Doctor of Philosophy Dissertation University of North Carolina at Chapel Hill Graduate School Degree granting institution Orlando Coronell Thesis advisor Mary Laura Lind Thesis advisor Richard Superfine Thesis advisor Rene Lopez Thesis advisor Wei You Thesis advisor text 2017-05 Perry_unc_0153D_16910.pdf uuid:c6a7a033-2828-49b8-8f6a-e054082b64b6 proquest 2019-07-06T00:00:00 2017-04-20T01:45:58Z application/pdf 15739081 yes