Water vapor transport properties of interfacially polymerized thin film nanocomposite membranes modified with graphene oxide and GO-TiO₂ nanofillers

Baig, Muhammad Irshad,Ingole, Pravin G.,Jeon, Jae-deok,Hong, Seong Uk,Choi, Won Kil,Lee, Hyung Keun Elsevier 2019 CHEMICAL ENGINEERING JOURNAL -LAUSANNE- Vol.373 No.-

<P><B>Abstract</B></P> <P>Graphene oxide (GO) and its composite with TiO<SUB>2</SUB> (GT) were utilized as nano-filler materials to prepare highly permeable and water vapor selective nanocomposite membranes. The nano-fillers were characterized using different analytical tools to determine their physicochemical properties. Nanocomposite membranes were prepared by dispersing the nano-fillers in aqueous phase monomer solution for interfacial polymerization reaction on the inner surface of Polysulfone hollow fiber membrane. Surface morphology and bonding chemistry of the nanocomposite membrane was analyzed using various analytical tools. The two types of nano-fillers were compared for their compatibility with the polyamide matrix, and consequently, the water vapor separation performance of the resulting membrane. Results revealed that both the nano-fillers are firmly attached to the polyamide layer via hydrogen and covalent bonds. GT based membranes have higher surface roughness and better hydrophilicity as compared to GO. In addition, GT membranes have more carboxyl groups and lesser degree of cross-linking due to the interference with interfacial polymerization reaction. This leads to a higher permeance (2820 GPU) and a water vapor/nitrogen selectivity when compared to other TFN membranes reported in literature. The nano-fillers act as active sites for preferential transport of water vapor molecules through the membrane thereby, significantly improving water vapor permeance.</P> <P><B>Highlights</B></P> <P> <UL> <LI> GO and GO-TiO<SUB>2</SUB> nanofillers were incorporated in polyamide nanocomposite membrane. </LI> <LI> Improved water vapor permeance was obtained from GO and GO-TiO<SUB>2</SUB> nanofillers incorporated TFN membranes. </LI> <LI> Highly hydrophilic TFN membranes were obtained for water vapor separation. </LI> <LI> GO-TiO<SUB>2</SUB> shows superior water vapor permeance than GO. </LI> <LI> Functionalized GO could improve water vapor permeation even further. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>GO and GO-TiO<SUB>2</SUB> incorporation in TFN membrane by interfacial polymerization for excellent water vapor separation performance.</P> <P>[DISPLAY OMISSION]</P>

RECENT Developments IN THE Robust Fabrication of Thin-film Nanocomposite Membranes for the Environmental Care

Yogita M.shirke,Seong-Jun Cho,Soon Jin Kwon,Won-Kil Choi,Seong Uk Hong,Jae-Deok Jeon 한국에너지기후변화학회 2021 한국에너지기후변화학회 학술대회 Vol.2021 No.11

Power generation in recent decades has been carried out by coal-fired power plants, which use coal to generate electricity. Burning of coal is generated large quantities of flue gas which contains N₂, O₂, CO₂, nitrogen oxides (NOx), sulfur oxides (SOx), fly ash, and water vapor. Lots of water vapor discharged from stacks and cooling towers of factories into the atmosphere is a serious crisis, as global warming is growing and more consumption of the limited water resources. In addition, white flume produced by condensing water vapor from flue gas becomes a cause of visual pollution. In the presence of a large amount of water vapor in the stack, condensation can readily occur, resulting in corrosion. For these reasons, water vapor is preferably removed from flue gas. On the other hand, volatile organic compounds (VOCs) are a generic term for liquid or gaseous hydrocarbon compounds that are easily evaporated into the atmosphere due to their high vapor pressure. These VOCs are emitted from public power generation facilities, district heating facilities, petroleum refining facilities, private power generation facilities, organic chemical product manufacturing industries, and other combustible or noncombustible sources, resulting in leading to compromised air quality. Therefore, it is necessary to create a clean environment by removing not only water vapor but also VOCs. Many technologies are used to remove water vapor and VOCs, but they have their own characteristics. For example, heat treatment technology is more suitable for high VOC concentrations (preferred for large and medium-sized workplace), adsorption treatment technology is more suitable for low VOC concentrations (preferred for small and medium-sized workplace). Membrane-based technology does not require thermal regeneration and phase change, and thus consumes less energy. Furthermore, it is compact, energy-efficient, easy to scale, low initial investment and simple to use and maintain. Therefore, membrane-based technology can be an attractive alternative that is used as a hybrid with existing technologies or to replace existing technologies to remove water vapor and VOCs. In this study, we propose a method of removing water vapor and VOCs together by using polymeric hollow fiber membranes. The polymeric membranes are coated with hydrophilic materials and hydrophobic materials to remove water vapor and VOCs, respectively. In order to further improve their performance, thin film nanocomposite (TFN) membranes with nanoparticles are also developed and tested the separation performance for environmental care.

Modeling and measurement of boiling point elevation during water vaporization from aqueous urea for SCR applications

Ho Jin Dan,JoonSikLee 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.3

Understanding of water vaporization is the first step to anticipate the conversion process of urea into ammonia in the exhaust stream. As aqueous urea is a mixture and the urea in the mixture acts as a non-volatile solute, its colligative properties should be considered during water vaporization. The elevation of boiling point for urea water solution is measured with respect to urea mole fraction. With the boiling-point elevation relation, a model for water vaporization is proposed underlining the correction of the heat of vaporization of water in the urea water mixture due to the enthalpy of urea dissolution in water. The model is verified by the experiments of water vaporization as well. Finally, the water vaporization model is applied to the water vaporization of aqueous urea droplets. It is shown that urea decomposition can begin before water evaporation finishes due to the boiling-point elevation.

Control of Water Vapor Permeation through Oxide Films on Polymers for Flexible Displays

( Won Hoe Koo ),( Sang Hun Choi ),( Hong Koo Baik ),( Sung Man Lee ),( Se Jong Lee ) 대한금속재료학회 ( 구 대한금속학회 ) 2005 ELECTRONIC MATERIALS LETTERS Vol.1 No.2

Composite films consisting of tin oxide and silicon oxide produced via thermal evaporation were deposited on polycarbonate substrates as water-barrier films to control the polarizability and packing density of the composite films, both of which are factors significantly affecting water vapor permeation through the films. As the tin oxide was added to the silicon oxide, the polarizability and packing density of the composite films increased, and the water vapor transmission rate (WVTR) through the composite oxide films decreased. Because of their strong interaction with water vapor, the 80 % tin oxide films with the highest polarizability and packing density showed the lowest WVTR; however, the loose microstructures, which were caused by thermal evaporation, resulted in a WVTR still too high to be applied as passivation layers in organic light emitting diodes. Therefore, we deposited SnO2 films with high polarizability on polycarbonate substrates while using an ion-beam-assisted deposition process (IBAD) to increase the packing density. This process resulted in a WVTR below the measurable limit of 0.01 g/㎡/day at 100% RH and 37.8℃. The permeation mechanism of water vapor through the oxide films is discussed in terms of the chemical interaction with water vapor and the microstructure of the oxide films. The chemical interaction of water vapor with oxide films was investigated by the refractive index obtained from ellipsometry and the OH group peak obtained from x-ray photoelectron spectroscopy (XPS). The microstructure of the composite oxide films was characterized using atomic force microscopy (AFM) and transmission electron microscopy (TEM). The activation energy for water vapor permeation through the oxide films was also measured in relation to the permeation mechanism of water vapor.

Membrane dehumidification process using defect-free hollow fiber membrane

Kim, Kee Hong,Ingole, Pravin G.,Lee, Hyung Keun Elsevier 2017 International journal of hydrogen energy Vol.42 No.38

<P><B>Abstract</B></P> <P>Water vapor removal by the polymeric membrane to reduce the energy cost during the water–gas shift reaction in a catalytic membrane reactor was investigated. In this study, polyamideimide (PAI) defect-free hollow fiber membranes were produced by a dry/wet phase inversion method. The purpose of this study was to investigate the water vapor removal efficiency under high pressure and high temperature. The morphologies of the hollow fiber membranes were characterized by SEM. The water vapor and hydrogen mixed gas separation properties were used to verify the performance of a defect-free membrane. The water vapor removal efficiency increased from 54% to 90% (at 120 °C) as a function of the operating conditions because of the enhanced water vapor flux. However, the H<SUB>2</SUB> retention ratio was negatively related to the water removal efficiency.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Defect-free hollow fiber membranes were prepared for H<SUB>2</SUB>/water vapor separation. </LI> <LI> Water vapor removal efficiency increased from 54% to 90% (at 120 °C). </LI> <LI> The process with combined H<SUB>2</SUB> separation consumes less energy. </LI> </UL> </P>

Enhanced water vapor in Asian dust layer: Entrainment processes and implication for aerosol optical properties

Yoon, Soon-Chang,Kim, Sang-Woo,Kim, Jiyoung,Sohn, Byung-Ju,Jefferson, Anne,Choi, Suk-Jin,Cha, Dong-Hyun,Lee, Dong-Kyou,Anderson, Theodore L.,Doherty, Sarah J.,Weber, Rodney J. Elsevier 2006 Atmospheric environment Vol.40 No.13

<P><B>Abstract</B></P><P>The entrainment process of water vapor into the dust layer during Asian dust events and the effect of water vapor associated with the Asian dust layer (ADL) on aerosol hygroscopic properties are investigated. The entrainment processes of water vapor into the ADL is examined by using a PSU/NCAR MM5 together with the backward trajectory model, radiosonde data, and remotely sensed aerosol vertical distribution data. Two dust events in the spring of 1998 and 2001 are examined in detail. The results reveal that the water vapor mixing ratio (WVMR) derived by the MM5 fits in well with the WVMR observed by radiosonde, and is well coincident with the aerosol extinction coefficient (<I>σ</I><SUB>ep</SUB>) measured by the micro-pulse lidar. The temporal evolution of the vertical distributions of WVMR and <I>σ</I><SUB>ep</SUB> exhibited similar features. On the basis of a well simulation of the enhanced water vapor within the dust layer by the MM5, we trace the dust storms to examine the entrainment mechanism. The enhancement of WVMR within the ADL was initiated over the mountainous areas. The relatively moist air mass in the well-developed mixing layer over the mountainous areas is advected upward from the boundary layer by an ascending motion. However, a large portion of the water vapor within the ADL is enhanced over the edge of a highland and the plains in China. This is well supported by the simulated WVMR and the wind vectors. Aircraft-based in situ measurements of the chemical and optical properties of aerosol enable a quantitative estimation of the effect of the enhanced WVMR on the aerosol hygroscopic properties. The submicron aerosol accompanied by the dust storm caused an increase of aerosol scattering through water uptakes during the transport. This increase could be explained by the chemical fact that water-soluble submicron pollution aerosols are enriched in the ADL.</P>

Deposition Mechanisms of MOCVD Copper Films in the Presence of Water Vapor

Kim, Jung-Yeul 위덕대학교 부설 전자기술연구소 1997 전자기술연구소 논문집 : 위덕대 Vol.1 No.1

The effect of water vapor on the initial nucleation and growth mechanisms of metallo-organic chemical vapor deposited (MOCVD) copper films from copper(Ⅱ) hexafluoroacetylacetonate [Cu(hfac)_(2)] on a pre-deposited Cr substrate has been investigated. A relatively low growth rate with a long incubation period was observed in the absence of water vapor. When an optimum water vapor flow rate was introduced into the system, enhanced growth rate was observed without sacrificing electrical properties of the copper film. However, XRD analysis of the initial deposited film revealed that the film was mainly composed of copper oxide (Cu_(2)O). The oxygen in copper oxide films deposited from Cu(hfac)_(2) on pre-deposited Cr substrates is derived from water vapor not the hfac ligand. Initial nucleation and growth of the deposited film is initiated by the reaction between the vapor phase precursor and water vapor forming copper oxide (Cu_(2)O) at the surface and the oxide is then reduced to metallic copper by either a disproportional in reaction or by hydrogen molecules. The optimum water vapor flow rate is thus believed to be the driving force for the enhanced growth rate with a reduced nucleation delay and without degrading the film resistivity.

Role of functional nanoparticles to enhance the polymeric membrane performance for mixture gas separation

Ingole, Pravin G.,Baig, Muhammad Irshad,Choi, Wook,An, Xinghai,Choi, Won Kil,Lee, Hyung Keun Elsevier 2017 Journal of industrial and engineering chemistry Vol.48 No.-

<P><B>Abstract</B></P> <P>To improve the water vapor/gas separation the hydroxylated TiO<SUB>2</SUB> (OH-TiO<SUB>2</SUB>) nanopartilces have been synthesized and surface of polysulfone (PSf) hollow fiber membrane (HFM) has been coated as thin film nanocomposite (TFN) membranes. To remove the water vapor from mixture gas, hollow fiber membrane has been fabricated and while coating, the OH-TiO<SUB>2</SUB> nanoparticles have been incorporated in the <I>m</I>-phenylenediamine (MPD) solution to make TFN membrane. Aqueous MPD—OH-TiO<SUB>2</SUB> nanoparticles mix solutions and organic trimesoyl chloride (TMC) were used to prepare the TFN membranes on the surface of the PSf HFM substrate. Pristine TiO<SUB>2</SUB> surface was modified to initiate functional groups on the TiO<SUB>2</SUB> surface to increase the hydrophilicity of the nanoparticles. Fourier transform infrared (FT-IR) spectroscopy was used to confirm the hydroxylation of TiO<SUB>2</SUB> nanoparticles. The membranes were well characterized using different physicochemical characterization techniques. The membrane performances were evaluated based on water vapor permeance, selectivity, water vapor flux and water vapor removal efficiency. Obtained experimental results designated that the incorporated OH-TiO<SUB>2</SUB> nanoparticles were dispersed well while interfacial polymerization in the TFN layer and their addition enhanced membrane performances. With an increasing concentration of OH-TiO<SUB>2</SUB> nanoparticles from 0.025 to 0.2wt.% compare with MPD solution during the fabrication, water vapor permeance and selectivity significantly enhanced due to the amplified water vapor permeation corridors afforded by the modified OH-TiO<SUB>2</SUB> nanoparticles. After increasing the concentration of OH-TiO<SUB>2</SUB> more than 0.2wt.% in the monomer solution the agglomeration was started. The results revealed that the addition of modified hydroxylated TiO<SUB>2</SUB> in MPD solution up to 0.2w/w% (membrane sample TFN-4 (MT(0.5, 0.2)-OH-TiO<SUB>2</SUB>-0.2)) increased the permeate flux and showed the best permeance 1396 GPU and selectivity 510 among the all prepared membranes.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Hydrophilic functional TiO<SUB>2</SUB> NPs are synthesized to prepare TFN membranes. </LI> <LI> Interfacial interactions between MPD, TMC and OH-TiO<SUB>2</SUB> nanoparticles are studied. </LI> <LI> The incorporated 0.2wt.% OH-TiO<SUB>2</SUB> nanoparticles show superior results. </LI> <LI> The relationship between TNF morphology and performance is investigated. </LI> <LI> Tunable water vapor permeance and selectivity are achieved. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Dispersion and removal characteristics of tritium originated from nuclear power plants in the atmosphere

Chae, Jung-Seok,Kim, Guebuem Elsevier 2018 JOURNAL OF ENVIRONMENTAL RADIOACTIVITY Vol.192 No.-

<P><B>Abstract</B></P> <P>The activities of tritium in water-vapor (<I>n</I> = 649) and precipitation (<I>n</I> = 2404) samples were measured from 1998 to 2015 around the Wolsong nuclear power plant (NPP) site where four pressurized heavy water reactors and two pressurized water reactors operated. The activity concentrations of tritium in the water-vapor and precipitation samples were in the ranges of 2.2–2200 Bq/L and 0.3–1090 Bq/L, respectively. The concentrations of tritium in the water-vapor in spring were approximately 7 times higher than those in fall and winter, mainly owing to the wind directions at the power plant location. The annual geometric mean activities of tritium in the water-vapor and precipitation samples varied within 56% and 83% from the average, respectively, depending primarily on the annual discharge amount of tritium to the atmosphere. The activities of tritium in the water-vapor and precipitation samples rapidly decreased away from the power plant. Approximately 0.5–30% of tritium discharged from the NPP site was removed by precipitation to the ground within an area with a radius of 30 km from the NPP site, which linearly depended on the precipitation amount. Our results suggest that the wind direction and precipitation, in addition to the amount of discharge, are important factors that control the tritium concentrations in air near the NPP site.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The tritium concentration in the water vapor and precipitation near NPP was measured. </LI> <LI> Approximately 0.5–30% of tritium released from the NPP was removed by precipitation. </LI> <LI> The removed amount of tritium linearly depended on the precipitation amount. </LI> </UL> </P>

건축 외벽용 유기 용제형 및 수성 발수제의 성능 분석

서상교,정면화 충북대학교 건설기술연구소 2003 建設技術論文集 Vol.22 No.2

As solvent-based water repellents need organic solvents that are highly flammable for dilution, the operators may exposed to danger and inhalation and it may cause environmental issues as well due to the emission of organic solvents. This research aims to evaluate the properties of solvent-based and water-based water repellents, to analyze the results and to see the possibility that water-based material can substitute for solvent-based water repellents. The comparison experiments show that there are no big properties differences between water-based and solvent-based water repellents in all performances tested in this research except penetration. In conclusion, water-based water repellents can come up with the solvent-based products in water absorption rate, efflorescence resistivity and water vapor transmission, but is required to improve the penetration. However, the results say that water-based water repellents can replace solvent-based material. For the healthy living environment and the lifetime retention of building, the water permeation to building inside should be prevented and the water generated or permeated in the buildings should be evaporated atmosphere as soon as possible. Generally, the waterproof material like asphalt or paint film can repel water, but they can't expel the water generated inside properly. To prevent the ingress of moisture and water from the outside without suppressing the outward transport of moisture formed inside of building, many silicone-based water repellents are used worldwide and the volume of their consumption is increasing rapidly.