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Effects of electrostatic interaction in adsorptive removal of organic dyes by Ti3C2-MXenes
임세형,김진형,박현수,곽채수,김지은,양지원,유승영,이주형 한국공업화학회 2020 한국공업화학회 연구논문 초록집 Vol.2020 No.-
MXenes, a new class of 2D materials, have recently attracted considerable attention as a promising adsorbent in environmental remediation. It was previously shown that some selected aqueous organic dyes were successfully sequestrated by MXenes yet a systematic investigation on the adsorptive performance of MXenes for a wide variety of dyes still lacks in more realistic aquatic environments than a clean lab deionized water. Herein, we investigate the adsorptive performance of delaminated Ti3C2-MXenes for six different organic dyes in aquatic media with various pH values and ionic strengths. The results strongly suggest the importance of electrostatic interaction between the ionizable functional groups of MXenes and dyes in the removal efficiency, providing a rational strategy to optimize the aquatic conditions for efficient removal of different types of organic dyes.
Stable Colloidal Dispersion of Octylated Ti<sub>3</sub>C<sub>2</sub>-MXenes in a Nonpolar Solvent
임세형,박현수,양지원,곽채수,이주형 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.0
Two-dimensional (2D) early transition metal carbides and/or nitrides (MXenes) have shown significant potential in a wide variety of applications. The majority of MXene research has utilized aqueous colloidal dispersions of MXenes because of the unique hydrophilicity of the MXene surface. In some cases, however, aqueous dispersions have various disadvantages such as the degradation of MXenes in long-term storage and incompatibility with water-insoluble polymers. Herein, we demonstrated a stable nonpolar colloidal dispersion of MXenes chemically grafted with lipophilic octyltriethoxysilanes. A high grafting density of OTS on the MXene surface was achieved by employing a strong acid polyelectrolyte as an OTS (water insoluble)-in-water emulsifier.. Despite the negligible surface charging, the hydrophobic MX@OTS showed excellent colloidal stability in very nonpolar hexanes over 4 weeks.
임세형,박현수,김진형,양지원,곽채수,김지은,유승영,이주형 한국공업화학회 2020 한국공업화학회 연구논문 초록집 Vol.2020 No.-
MXenes are recently gaining significant attention for numerous environmental applications owing to their superior hydrophilicity and unique surface functionalities. However, the use of MXenes for in-situ remediation of contaminated subsurface aquatic environments has not been considered yet. For effective in-situ remediation, it is of primary importance to maintain colloidal stability in harsh subsurface environments. Herein, Ti3C2-MXenes covalently grafted with polyelectrolytes (PEs), MXene-g-PEs, are developed by employing either anionic or zwitterionic PEs. Both MXene-g-PEs have sufficient colloidal stability against the immediate and irreversible aggregation observed for the pristine MXenes in API brines. The MXenes-g-(zwitterionic) PEs show long-term colloidal stability over 6 months in API brine with extreme salinity and little adsorption against α-alumina surfaces. The results suggest a high potential usefulness of the MXene-g-PEs in various subsurface applications.
박현수,임세형,양지원,곽채수,김지은,최신식,김채빈,이주형 한국공업화학회 2020 한국공업화학회 연구논문 초록집 Vol.2020 No.-
Nanoparticles (NPs) may have great potential for various subsurface applications over the past decades. One of the important challenges for these applications is to achieve colloidal stability in subsurface media at high salinity and high temperature. It has been previously shown that NPs “multipoint”-grafted with anionic poly(AMPS-co-AA) exhibited remarkable colloidal stabilities in certain salinity such as API brine. However, many other important properties of such particles still remain unstudied. Herein, we investigate various properties of the silica (SiO<sub>2</sub>) NPs “multipoint”-grafted with poly(AMPS-co-AA) in NaCl and CaCl<sub>2</sub> solutions. The brush behavior of the grafted random copolymers was investigated through wide range of salinities. The particles displayed brine-oil interfacial activity with increasing salt concentrations (C<sub>s</sub>), stabilizing oil-in-brine emulsions. High internal phase emulsion (HIPE) could be formed in high C<sub>s</sub> of CaCl<sub>2</sub>, which exhibited gel-like behavior.
Noncovalent grafting of polyelectrolytes onto hydrophobic polymer colloids with a swelling agent
박현수,임세형,양지원,곽채수,이주형 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.0
Often it is not feasible to graft hydrophilic polymer stabilizers covalently to polymer colloids as reactive binding sites are either not available or would interfere with the functional properties. Here, we present facile, general and scalable physical protocols for permanent noncovalent grafting of polyelectrolytes to hydrophobic polymeric nanoparticles with chemically inert surfaces using polyurea and polyurethane polymer nanocapsules as examples. The polyelectrolytes are adsorbed and physically entangled within a partially liquefied polymer surface upon adding a small amount of organic solvent as a swelling agent.
Properties of Pickering Emulsions Stabilized by Naturally Occuring Microparticles
양지원,박현수,임세형,곽채수,이주형 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.0
Plant pollens, naturally occurring microparticles, have gained much interest from various research areas owing to the unique architecture, mechanical properties, and resistance to biological degradation as well as chemical attack. In this study, we revisit the properties of Pickering emulsions of oil and water mixtures stabilized by the bee pollens. Interfacial tensions of various types of oils and water containing the dispersed pollen microparticles were systematically investigated. The significant reduction in the measured IFTs from those of the oils with pure particle-free water, in virtually all oil-water cases, strongly suggest the amphiphilic nature of the bee pollens, and hence the potential of the bee pollens in utilization as Pikcering emulsifers for versatile oil-water interfaces. Pickering emulsions prepared with the bee pollens in various experimental conditions, which were oil-in-water in most cases, displayed the remarkable stability for several months.
곽채수,박현수,김준혁,임세형,양지원,김지은,김지은,이준협,이주형 한국공업화학회 2020 한국공업화학회 연구논문 초록집 Vol.2020 No.-
Phase change material emulsions (PCMEs) are an attractive two-phase heat transfer fluid where the PCMs that can store or release latent heats during their phase change at a desired temperature are dispersed in the form of fine droplets in a carrier fluid. The majority of the PCMEs were prepared previously by using organic molecular surfactants, some of which might possess health and environmental risks. Herein, we demonstrate the surfactant-free fabrication of docosane (C<sub>22</sub>H<sub>46</sub>)-based PCMEs by utilizing various mineral oxide nanoparticles (MONPs) as Pickering emulsifiers, which showed promising thermal properties.
양지원,김지은,곽채수,박현수,임세형,유승영,이주형 한국공업화학회 2020 한국공업화학회 연구논문 초록집 Vol.2020 No.-
Capillary suspensions are ternary solid-liquid-liquid systems produced via the addition of a small amount of secondary fluid to the bulk fluid that contained the dispersed solid particles. The secondary fluid could exert strong capillary forces between the particles and dramatically change the rheological properties of the suspension. So far, research has focused on capillary suspensions that consist of additive-free fluids, whereas capillary suspensions with additives, particularly those of large molecular weight that are highly relevant for industrial purposes, have been relatively less studied. Here, we present our systematic study on the properties of capillary suspensions with secondary phases containing a variety of water-soluble polymers.
양지원,곽채수,김지은,박현수,임세형,이주형 한국고분자학회 2020 Macromolecular Research Vol.28 No.3
Plant-based pollens have recently received significant attention in various fields owing to their numerous potential advantages including their unique architecture, mechanical strength, and high resistance to chemical attacks and biological degradation. In this study, we demonstrate viscoelastic Pickering emulsions of water and oil (trimethylolpropane trimethacrylate) stabilized by naturally occurring bee pollen microparticles. We systematically investigate the rheological properties of the pollen-stabilized emulsions with various pollen concentrations and water-to-oil ratios. It is observed that the emulsions prepared at a high pollen loading and an appropriate water-to-oil ratio show excellent shape retention and shear-thinning behaviors. The results suggest the possibility of utilizing pollen-stabilized Pickering emulsions for several applications including direct ink writing.