Magnetic mesoporous materials for removal of environmental wastes

Kim, Byoung Chan,Lee, Jinwoo,Um, Wooyong,Kim, Jaeyun,Joo, Jin,Lee, Jin Hyung,Kwak, Ja Hun,Kim, Jae Hyun,Lee, Changha,Lee, Hongshin,Addleman, R. Shane,Hyeon, Taeghwan,Gu, Man Bock,Kim, Jungbae Elsevier 2011 Journal of hazardous materials Vol.192 No.3

<P><B>Highlights</B></P><P>• Iron oxide particle embedded mesoporous silica and carbon are synthesized. • Both mesoporous materials are separated easily under aqueous condition using magnet. • Mercury or fluorescein is removed by using magnetic mesoporous material. • Tyrosinase is immobilized in magnetic mesoporous silica and reused after reaction. • Magnetic mesoporous materials are applicable to removal of environmental wastes.</P> <P><B>Abstract</B></P><P>We have synthesized two different magnetic mesoporous materials that can be easily separated from aqueous solutions by applying a magnetic field. Synthesized magnetic mesoporous materials, Mag-SBA-15 (magnetic ordered mesoporous silica) and Mag-OMC (magnetic ordered mesoporous carbon), have a high loading capacity of contaminants due to high surface area of the supports and high magnetic activity due to the embedded iron oxide particles. Application of surface-modified Mag-SBA-15 was investigated for the collection of mercury from water. The mercury adsorption using Mag-SBA-15 was rapid during the initial contact time and reached a steady-state condition, with an uptake of approximately 97% after 7h. Application of Mag-OMC for collection of organics from water, using fluorescein as an easily trackable model analyte, was explored. The fluorescein was absorbed into Mag-OMC within minutes and the fluorescent intensity of solution was completely disappeared after an hour. In another application, Mag-SBA-15 was used as a host of tyrosinase, and employed as recyclable catalytic scaffolds for tyrosinase-catalyzed biodegradation of catechol. Crosslinked tyrosinase in Mag-SBA-15, prepared in a two step process of tyrosinase adsorption and crosslinking, was stable enough for catechol degradation with no serious loss of enzyme activity. Considering these results of cleaning up water from toxic inorganic and organic contaminants, magnetic mesoporous materials have a great potential to be employed for the removal of environmental contaminants and potentially for the application in large-scale wastewater treatment plants.</P>

Photocatalytic CO₂ conversion on highly ordered mesoporous materials: Comparisons of metal oxides and compound semiconductors

Lee, Yoon Yun,Jung, Han Sol,Kim, Ji Man,Kang, Yong Tae Elsevier 2018 Applied Catalysis B Vol.224 No.-

<P><B>Abstract</B></P> <P>In this study, the ordered mesoporous metal oxides (TiO<SUB>2</SUB> and SnO<SUB>2</SUB>) and compound semiconductors (ZnS, ZnSe, CdS, and CdSe) are manufactured and they exhibit several micrometers (μm) of particle size, and high surface area of about 100m<SUP>2</SUP>g<SUP>−1</SUP>. Well-developed crystallinities are prepared <I>via</I> simple nano-replication method by using a 3-D bicontinuous cubic <I>Ia</I>3<I>d</I> meso-structured ordered mesoporous silica KIT-6 as a hard-template. The visible-light-driven photocatalytic CO<SUB>2</SUB> conversion into CH<SUB>4</SUB> is carried out in the presence of H<SUB>2</SUB>O over various mesoporous materials. Prepared mesoporous materials show different light absorption behaviors and photocatalytic activities for conversion of CO<SUB>2</SUB>. The mesoporous compound semiconductors show higher CO yield rates than the mesoporous metal oxides, while mesoporous metal oxides show higher CH<SUB>4</SUB> yield rates than the mesoporous compound semiconductors. Compared to the commercial TiO<SUB>2</SUB> material (P25, Degussa), the mesoporous metal oxides (TiO<SUB>2</SUB>, SnO<SUB>2</SUB>) show 9 to 10 times higher yields of CH<SUB>4</SUB> and 2 to 3 times higher yields of CO owing to their high surface area. Especially, the mesoporous ZnS shows the highest CH<SUB>4</SUB> yield rate (3.620μmolg<SUB>cat</SUB> <SUP>−1</SUP>h<SUP>−1</SUP>) and the mesoporous CdSe shows the highest CO yield rate (5.884μmolg<SUB>cat</SUB> <SUP>−1</SUP>h<SUP>−1</SUP>) out of all photocatalysts considered in the present study. Although mesoporous CdS and ZnSe have great visible light absorption properties, they show relatively low CH<SUB>4</SUB> yield rates.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Highly ordered mesoporous metal oxides and compound semiconductors are manufactured. </LI> <LI> The photocatalytic CO2 conversion experiments are carried out on various mesoporous materials. </LI> <LI> Mesoporous ZnS photocatalyst shows the highest CH4 yield rate. </LI> <LI> Mesoporous CdSe photocatalyst shows the highest CO yield rate. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Average yield rates of CH<SUB>4</SUB> and CO by using various photocatalysts.</P> <P>[DISPLAY OMISSION]</P>

Synthesis of mesoporous siliceous materials in choline chloride deep eutectic solvents and the application of these materials to high-performance size exclusion chromatography

( Lixiaoxia ),( Xiaoqin Wang ),노경호 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.0

Mesoporous materials were prepared in choline chloride deep eutectic solvents by triblock copolymer-templated hydrothermal synthesis. The mesoporous material-based choline chloride-ethylene glycol (1:2 mole ratio) DES had a flower-type shape, but the material-based choline chloride-urea (1:2) and based choline chloride-acetic acid (1:2) had mesoporous spherical shapes. These mesoporous materials were applied to HPSEC column packing. The separation effect of the two dextrans was better from the choline chloride-acetic acid deep eutectic solvent-based mesoporous spheres packed in a high-performance SEC column. In addition, the three polysaccharides, dextran-1 (molecular weight: 670 KD), dextran-2 (molecular weight: 50 KD) and dextran-3 (molecular weight: 5 KD), were separated successfully using the choline chloride-acetic acid deep eutectic solvent-based mesoporous spheres packed in a high-performance size exclusion chromatography column.

Design of functional mesoporous materials

유룡 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.0

Mesoporous materials’ refers to highly porous materials in which the pore diameters belong to the mesopore range, i.e., 2~50 nm. The first designed synthesis of mesoporous materials with uniform pore arrangement and diameters was reported as ‘MCM-41’ silica by Mobil researchers in 1992. Since then, the research area on mesoporous materials grew enormously, leading to numerous practical and potential applications in adsorption, separation, drug delivery, electrical energy storage and catalysis. In the present conference, I would like to introduce major leaps for synthesis of such functional mesoporous materials. In particular, this talk will emphasize a recent synthetic strategy developed in my laboratory toward hierarchical structure direction using heteroatomcontaining surfactants and polymers.

A shelf-life study of silica- and carbon-based mesoporous materials

Emma M. Björk,Aylin Atakan,Pei-Hsuan Wu,Alessandra Bari,Carlotta Pontremoli,Kai Zheng,Dimitra Giasafaki,Giorgio Iviglia,Elisa Torre,Clara Cassinelli,Marco Morra,Theodore Steriotis,Georgia Charalambopo 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.101 No.-

Mesoporous silica- and carbon-based materials, including bioactive glasses, have proven potential ascomponents of medical devices and as drug carriers. From an application perspective, knowledge aboutthe shelf-life stability of these materials under various conditions is vital. Here, mesoporous bioactiveglasses (MBGs) synthesized by aerosol-assisted spray-drying and by a batch sol–gel method, mesoporoussilicas of SBA-15 type, and mesoporous carbons CMK-1 and CMK-3 have been stored under varying conditions,e.g. at different temperature and relative humidity (RH), and in different storage vessels. Theresults show that the silica-based materials stored in Eppendorfs are sensitive to humidity. Spray driedMBGs decompose within 1 month at a RH >5%, whilst sol–gel MBGs are more stable up to a RH >60%. Changing the storage vessel to sealed glass flasks increases the MBGs lifetime significantly, with nodegradation during 2 months of storage at a RH = 75%. SBA-15 stored in Eppendorfs are more stable comparedto MBGs, and addition of F- ions added during the synthesis affects the material degradation rate. Mesoporous carbons are stable under all conditions for all time points. This systematic study clearlydemonstrates the importance of storage conditions for mesoporous materials which is crucial knowledgefor commercialization of these materials.

Mesoporous Materials with Spherical Morphology : Synthesis and Bioapplication

Yang, Haifeng,Yan, Yan,Zhao, Dongyuan 한국공업화학회 2004 Journal of Industrial and Engineering Chemistry Vol.10 No.7

Morphology control is one of the most interesting issues in the research field of mesoporous materials. It plays a very important role in understanding the basic synthesis mechanism of the kind of materials. Moreover, the future applications of mesoporous materials are strongly depended on their tunable macroscopical morphologies. Mesoporous materials with spherical morphology are quite attractive due to the potential applications in macromolecular separations, drug deliveries, catalysis supports and template agents for photonic crystals. Researches on synthesis and properties of the materials have been carried out for nearly ten years. In this article, several synthetic methods for both siliceous and non-siliceous mesoporous spheres are reviewed, including solution self-assembly, aerosol spraying and hard templating route. The mechanism of self-assembly in solution system is provided and the rational controls for synthetic conditions are specifically discussed. With the viewpoint of applications, some examples are given in the aspects of bioseparations, drug delivery and catalysis. A short summary has listed some overviews for future developments.

Synthesis and Characterization of Mesoporous Mixed Metal Oxides based on CuO

전보경,박수빈,박귀옥,김지만 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.1

Ordered mesoporous materials have been widely used due to their properties such as high specific surface area, uniform pore diameter and stability for recyclability as electrode materials. In addition, transition metal oxides (TMOs), especially binary and ternary TMOs are prospective materials in catalysis and energy conversion and storage like solar cells, LIBs, and supercapacitors. Among TMOs, copper oxide (CuO) is one of the attracting materials owing to its high theoretical capacity as an electrode, abundance, environmental friendliness, nontoxicity, and inexpensiveness. Therefore, expecting the synergic effects of mesoporous CuO and TMOs, we synthesized several mesoporous mixed metal oxides (MMOs) based on CuO. In a hard templating method, the cubic Ia3d mesoporous silica KIT-6 was prepared to synthesize ordered mesoporous CuO and CuO-based MMOs. The materials are characterized by powder X-ray Diffraction, N₂ adsorption- desorption isotherm analysis, scanning electron microscopy.

Topological Transformation of Thioether-Bridged Organosilicas into Nanostructured Functional Materials

Kim, Jung Ho,Fang, Baizeng,Song, Min Young,Yu, Jong-Sung American Chemical Society 2012 Chemistry of materials Vol.24 No.12

<P>The strong interest in nanostructured functional materials has motivated the scalable production of high quality mesoporous silicas and carbonaceous materials. Although many approaches have been explored for this goal, it is highly desired and still remains a challenge to develop a straightforward strategy for simple and cost-effective fabrication of nanostructured functional materials. Here we demonstrate a simple sol–gel preparation of bis[3-(triethoxysilyl)propyl]tetrasulfide-based organosilica nanostructured materials and their topological transformations, through which porous spherical silica or carbon and hollow silica or carbon capsule are synthesized. As a representative application, the hollow carbon capsule is employed as a catalyst support for dispersion of high loading of Pt, which exhibits much higher catalytic activity toward oxygen reduction reaction than other porous carbon materials prepared in this work due to its larger surface area and mesoporous volume, particularly the unique architecture composed of a hollow macroporous core and a mesoporous shell, facilitating not only small size and good dispersion of Pt nanoparticles but also fast mass transport.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/cmatex/2012/cmatex.2012.24.issue-12/cm203520a/production/images/medium/cm-2011-03520a_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/cm203520a'>ACS Electronic Supporting Info</A></P>

In operando synchrotron small-angle X-ray scattering study of ordered mesoporous materials: tracking the nanostructure change

박귀옥,박수빈,김경호,전보경,김지만 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.0

We herein report an in operando probing of mesoscopic structural changes in ordered mesoporous electrode materials during cycling with synchrotron-based small angle X-ray scattering (SAXS) technique. In operando SAXS studies combined with electrochemical and other physical characterizations straightforwardly show how porous electrode materials underwent volume changes during the whole process of charge and discharge, with respect to their own reaction mechanism with lithium. This comprehensive information on the pore dynamics as well as volume changes of the electrode materials will not only be critical in further understanding of lithium ion storage reaction mechanism of materials, but also enable the innovative design of high performance nanostructured materials for next generation batteries.

Non-siliceous ordered mesoporous materials via nanocastingfor small molecule conversion electrocatalysis

Du San Baek,Sang Hoon Joo 대한화학회 2022 Bulletin of the Korean Chemical Society Vol.43 No.10

Since the pioneering work of Ryoo and co-workers in 1999 on the synthesis ofordered mesoporous carbons via nanocasting, the nanocasting pathway hasendured the test of time and has established itself as a robust and versatilemethod for preparing ordered mesoporous materials (OMMs). This methodenables the generation of a remarkably wide range of non-siliceous OMMs,some of which are otherwise inaccessible. In this account, we present ourdecade-long efforts toward the function-oriented design of non-siliceousOMM-based electrocatalysts for promoting small molecule conversion reac-tions relevant to renewable energy conversion and commodity chemical pro-duction, including hydrogen evolution reaction, oxygen evolution reaction, andselective oxygen reduction reaction. We also discuss the extension of the nano-casting concept to a silica-coating-mediated synthesis for preparing new cata-lytic materials. We conclude the account by suggesting the remainingchallenges and outlook for the future development of advanced OMMs.