• Membrane Journal
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• v.33 no.6
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• pp.416-426
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• 2023

In this study, hindered amine-grafted graphene oxide (HA-GO) with antioxidant properties was prepared and incorporated into Nafion-based composite membranes as an effective filler material for polymer electrolyte membrane fuel cell applications. HA-GO was synthesized via a ring-opening reaction between amine groups in 4-amino-2, 2, 6, 6-tetramethyl piperidine and epoxy groups on the surface of GO. Nafion-based composite membranes containing different weight contents of HA-GO were fabricated to compare the polymer electrolyte membrane properties with those of the pure Nafion membrane. The composite membranes with HA-GO were found to have better mechanical properties, chemical stability, and proton conductivity than the pure Nafion membrane. In particular, the conductivity retention behavior confirmed by the decrease in proton conductivity after Fenton's test of the composite membranes was better than that of the pure Nafion membrane due to the incorporation of HA-GO with effective antioxidant properties.

• Korean Chemical Engineering Research
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• v.50 no.5
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• pp.885-889
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• 2012

In this study, amine and metal oxide additives were investigated to improve $CO_2$ adsorption capacity of activated carbons (ACs). The characteristics of surface modified ACs were studied by X-ray photoelectron spectroscopy (XPS), $N_2$ adsorption, X-ray diffraction (XRD), and BET. Amine surface treatment decreased specific surface area and pore volume of ACs, but increased alkalinity by the incorporated nitrogen functional groups. Adsorption capacities of amine functionalized ACs was larger than original ACs, because basic group which can react with $CO_2$ was grafted on the ACs surface. Presence of copper oxides on ACs also enhances the carbon dioxide adsorption. The copper oxides could increase the adsorption rate of carbon dioxides due to the acid-base interaction (or electron acceptor-donor interaction). It was found that copper oxide loading was a promising method to improve the $CO_2$ adsorption capacity of ACs.

• Applied Chemistry for Engineering
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• v.26 no.3
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• pp.331-335
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• 2015

We prepared films by a bar-coating of various graphene oxide (GO) pastes by varying pH with amine compounds. The thermal treatment of films at $150^{\circ}C$ and measurement of surface resistances exhibited that the pH variation does not significantly affect the surface resistance. We, however, found that the addition of amines reduced the surface resistance by approximately 10 times and N,N-dimethylethanolamine (DMEA) showed the most significant effect among all amines investigated. XPS studies demonstrated that the addition of DMEA accelerated the reduction reaction of GO, and finally enhanced the electrical properties of GO films.

• Korean Journal of Materials Research
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• v.16 no.11
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• pp.687-691
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• 2006

Synthesis of Iron oxides by air oxidation of $FeSO_4$ solutions in the presence of NaOH, Diethylenetriamine (DETA), Butylamine (BA) and influence of ultrasonic wave were investigated by XRD, SEM and particle size analyzer. As the DETA addition increased to 0.05 mol, $Fe_3O_4$ was formed with goethite($\alpha$- FeOOH) and $Fe_3O_4$ single phase was formed above 0.18mol of DETA. As the BA addition increased, the XRD peak intensity of (020) face of lepidocrocite($\gamma$-FeOOH) was developed until the formation of $Fe_3O_4$ and reduced the size of the iron oxide particles formed. Ultrasonic wave reduced the size of the iron oxide particles but gave little effects on the iron oxide particles synthesized by amine.

• Carbon letters
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• v.21
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• pp.1-7
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• 2017

The effects of ammonia-treated graphene oxide (GO) on composites based on epoxy resin were investigated. Ammonia solutions of different concentrations (14-28%) were used to modify GO. Nitrogen functional groups were introduced on the GO surfaces without significant structural changes. The ammonia-treated GO-based epoxy composites exhibited interesting changes in their mechanical properties related to the presence of nitrogen functional groups, particularly amine ($C-NH_2$) groups on the GO surfaces. The highest tensile and impact strength values were 42.1 MPa and 12.3 J/m, respectively, which were observed in an epoxy composite prepared with GO treated with a 28% ammonia solution. This improved tensile strength was 2.2 and 1.3 times higher than those of the neat epoxy and the non-treated GO-based epoxy composite, respectively. The amine groups on the GO ensure its participation in the cross-linking reaction of the epoxy resin under amine curing agent condition and enhance its interfacial bonding with the epoxy resin.

• Proceedings of the Korean Society of Toxicology Conference
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• 2002.05a
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• pp.100-100
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• 2002

2-amino-3-methylimidazo[4,5-f]quinoline (IQ), a heterocyclic amine, significantly inhibits nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated macrophages. The decrease in NO production was found to correlate well with a decrease in iNOS mRNA expression as demonstrated by Northern blot analysis.(omitted)

• Bulletin of the Korean Chemical Society
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• v.32 no.4
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• pp.1133-1137
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• 2011

Ordered array of gold nanoparticles (Au NPs) over ITO glass was investigated in terms of ITO pretreatment, particle size, and diamines with different chain length. Owing to the indium-tin-oxide (ITO) layer coated on the glass, the substrate surface has a limited number of hydroxyl groups which can produce functionalized amine groups for Au binding, which resulted in the loosely-packed array of Au NPs on the ITO surface. Diamine ligand as a molecular linker was introduced to enhance the lateral binding of adjacent Au NPs immobilized on the amine-functionalized ITO glass, consequently leading to the densely-packed array of Au NPs over the ITO substrate. The molecular bridging effect was strengthened with the increase of chain length of diamines: C-12 > C-8. The packing density of small Au NPs (< 40 nm) was significantly increased with the increase of C-8 diamine, but large Au NPs (> 60 nm) did not produce densely-packed array on the ITO glass even for the dosage of C-12 diamine.

• Korean Chemical Engineering Research
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• v.61 no.4
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• pp.635-644
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• 2023

Due to the rapid development of the livestock industry, particularly due to residual pharmaceutical antibiotics, environmental populations have been negatively affected. Herein, we report a ZnO/melamine-functionalized carboxylic-rich graphene oxide (ZFG) photocatalyst for visible light-driven photocatalytic degradation of tetracycline hydrochloride in aqueous solutions. The properties of the photocatalysts were evaluated by XRD, FTIR, XPS, Fe-SEM, HR-TEM, TGA, Raman spectroscopy, UV-Vis spectroscopy, zeta potential, and electrochemical measurements. The photocatalytic activity was measured using high-performance liquid chromatography. The photocatalytic properties of the ZFG photocatalyst evaluated against the tetracycline hydrochloride (TCH) antibiotic under visible light irradiation showed superior photodegradation of 96.27% within 60 min at an initial pH of 11. The enhancement of photocatalytic degradation was due to the introduction of functionalized graphene, which increases the light-harvesting capability and molecular adsorption capability in addition to minimizing the recombination rate of photogenerated charge carriers due to its role as an electron acceptor and mediator.

• Journal of the Korean Applied Science and Technology
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• v.33 no.1
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• pp.23-29
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• 2016

Zinc oxide of hexagonal wurzite, is known as n-type semiconductor. It has a wide band gap energy of 3.37 eV and large exciton binding energy of 60 meV. It can be widely applied to gas sensors, laser diodes, dye-sensitized solar cells and degradation of dye waste. The use of microwave hydrothermal synthesis brings a rapid reaction rate, high yield, and energy saving. Amine additives control the different particle shapes because of the chelate effect and formation of hydroxide ion. In this study, zinc nitrate hexahydrate was used as zinc precursor. In addition, ethanolamine, ethylenediamine, diethylenetriamine, and hexamethylenetetramine are used as shape control agent. The pH value was controlled as 11 by NaOH. The shapes of zinc oxide are star-like, rod, flower-like, and circular cone. In order to analyze physical, chemical, and optical properties of ZnO with diverse amine additives, we used XRD, SEM, EDS, FT-IR, UV-Vis spectroscopy, and PL spectroscopy.

• Korean Journal of Chemical Engineering
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• v.35 no.11
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• pp.2220-2231
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• 2018

Lipase from Candida rugosa was immobilized on $MgO{\cdot}SiO_2$ hybrid grafted with amine, thiol, cyano, phenyl, epoxy and carbonyl groups. The products were analyzed using Fourier transform infrared spectroscopy, nuclear magnetic resonance, low-temperature $N_2$ sorption and elemental analysis. Additionally, the degree of coverage of the oxide material surface with different functional groups and the number of surface functional groups were estimated. The Bradford method was used to determine the quantity of immobilized enzyme. The largest quantity of enzyme (25-28 mg/g) was immobilized on the hybrid functionalized with amine and carbonyl groups. On the basis of hydrolysis reaction of p-nitrophenyl palmitate to p-nitrophenol, it was determined how the catalytic activity of the obtained biocatalysts is affected by pH, temperature, storage time, and repeated reaction cycles. The best results for catalytic activity were obtained for the lipase immobilized on $MgO{\cdot}SiO_2$ hybrids with amine and carbonyl groups. The biocatalytic system demonstrated activity above 40% in the pH range 4-10 and in the temperature range $30-70^{\circ}C$. Lipase immobilized on the $MgO{\cdot}SiO_2$ systems with amine and epoxy groups retains, respectively, around 80% and 60% of its initial activity after 30 days of storage, and approximately 60-70% after 10 reaction cycles.