• Journal of Conservation Science
• /
• v.33 no.1
• /
• pp.35-42
• /
• 2017

The Yeongheungdo shipwreck was excavated in the sea of Seomeopbeol, Ongjin-gun, Incheon, Korea. Chemical characterization of timbers from the shipwreck occurred via maximum moisture content, chemical composition, FT-IR, solid state $^{13}C$ NMR, and XRD analyses. As maximum moisture content of the outer part of the timbers averaged 623%, a phenomenon in that lignin increased relatively, according to the decrease in cellulose, and the ash content increased, which is typical of waterlogged archaeological wood was shown. The results from the FT-IR and solid state $^{13}C$ NMR analyses showed that the cellulose band of the outer part had disappeared or had remarkably decreased. In addition, the bands assigned to lignin dramatically increased. However, regarding the inner part of the timbers, hemicellulose and some crystalline cellulose and amorphous cellulose bands decreased. Therefore, a large difference exists between the degradation levels of the outer and inner parts of the timbers of the Yeongheungdo shipwreck.

• Journal of Korean Society of Environmental Engineers
• /
• v.31 no.9
• /
• pp.735-742
• /
• 2009

The bone of spinal animals has a hydroxylapatite ($Ca_{10}(PO_4)_6(OH)_2$, HAp) structure which is well known as an excellent inorganic ion exchanger for various heavy metal ions in solutions. In this study, the reusability of cow-bone, pig-bone and fish-bone as a potential material for the removal of heavy metals in solutions was evaluated from the removal of Cu(II) ion in batch tests. The surface properties of three bones, calcined at different temperatures, were measured with SEM, XRD, FT-IR analyses. From the SEM analysis, a clear development of heterogeneity as well as pores having small diameter was observed as the calcination temperature increased. The results of X-ray diffraction analysis showed well developed crystallinity on the surface of calcined bones obtained at higher temperatures, suggesting a transform of amorphous type to crystalline type. Fourier transform infrared (FT-IR) analysis showed disappearance of water molecule on the surface of HAp and organic functional groups of the HAp with increasing the calcination temperatures. Cu(II) removal in the control test was below 15%. By the way, additional 40% increase of Cu(II) removal was observed in the presence of calcined bones. For three bones, Cu(II) removal was decreased as the calcined temperature increased. Cu(II) removal was increased as the solution pH increased due to a favorable condition for the cation exchange as well as precipitation.

• Geomechanics and Engineering
• /
• v.31 no.3
• /
• pp.281-289
• /
• 2022

Bio-CaCO₃ is a blowout environment-friendly materials for soil improvement and sealing of rock fissures. To evaluate the chemical characteristics, shape, size and productivity of soybean urease induced CaCO₃ precipitates (SUICP), experimental studies were conducted via EDS, XRD, FT-IR, TGA, BET, and SEM. Also, the conversion rate of SUICP reaction at different time were determined and analyzed. The Bio-CaCO₃ product obtained by SUICP is comprehensively judged as calcite based on the results of EDS, XRD and FT-IR. The SUICP calcite precipitates are detected as spherical or ellipsoidal particles 3-6 ㎛ in diameter with nanoscale pores on their surface, and this morphology is novel. The median secondary particle size d₅₀ is 39-88 ㎛, indicating the agglomeration of the primary calcite particles. The Bio-calcite decomposes at 650-780℃, representing a medium thermal stability. The conversion rate of SUICP reaction can reach 80% in 24h, which is much more efficient than microbially induced CaCO₃ precipitation. These results reveal the knowledges of SUICP, and further direct its engineering applications. Moreover, we show an economic channel to obtain porous spherical calcite.

• Bulletin of the Korean Chemical Society
• /
• v.34 no.5
• /
• pp.1481-1486
• /
• 2013

Bifunctional Fe-SBA-15-$SO_3H$ mesoporous materials with different Si/Fe molar ratios (3, 5, and 7) have been synthesized via a simple direct hydrothermal method and characterized by XRD, $N_2$-adsorption/desorption, TG/DTG and FT-IR techniques, and used as solid acid catalysts in the esterification of lactic acid with methanol. XRD and $N_2$ sorption characterizations show successful iron doping within the mesoporous channels of SBA-15-$SO_3H$. The FT-IR and TG/DTG characterizations also reveal the presence of iron. With the incorporation of Fe ions into the SBA-15-$SO_3H$, the acid sites substantially increased because of the self-separated acidity of the hydrolysis of $Fe^{3+}$ solutions. However, in the Si/Fe = 3 molar ratio, the catalytic conversion decreased which is caused by the reduced cooperation effect between the acid pairs due to the weakened hydrogen bonds and collapse of the pore structure. This further suggests that the mesoporous structure decreases with the decrease in Si/Fe ratio.

• Journal of Sensor Science and Technology
• /
• v.26 no.6
• /
• pp.379-385
• /
• 2017

In this study, an amperometric non-enzymatic glucose sensor was developed on the surface of a glassy carbon electrode by simply drop-casting the synthesized homogeneous suspension of hexagonal boron nitride (h-BN) nanosheets with a copper metal-organic framework (Cu-MOF) composite. Comprehensive analytical methods, including field-emission scanning electron microscopy (FE-SEM), Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), cyclic voltammetry, electrochemical impedance spectroscopy, and amperometry, were used to investigate the surface and electrochemical characteristics of the h-BN-Cu-MOF composite. The FE-SEM, FT-IR, and XRD results showed that the h-BN-Cu-MOF composite was formed successfully and exhibited a good porous structure. The electrochemical results showed a sensor sensitivity of $18.1{\mu}A{\mu}M^{-1}cm^{-2}$ with a dynamic linearity range of $10-900{\mu}M$ glucose and a detection limit of $5.5{\mu}M$ glucose with a rapid turnaround time (less than 2 min). Additionally, the developed sensor exhibited satisfactory anti-interference ability against dopamine, ascorbic acid, uric acid, urea, and nitrate, and thus, can be applied to the design and development of non-enzymatic glucose sensors.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.5 no.3
• /
• pp.278-283
• /
• 1995

The potassium titanate fibres were synthesized with wet process by the addition of KOH solution to the TiOz gel produced by the reaction between element titanium particles and $H_2O_2$ solution at $50^{\circ}C$. And then they were characterized by XRD, SEM and FT - IR. It was found that potassium titanate fibres were mainly affected by KOH/TiOz mole ratio, synthesis time and aging time in this wet process employed. For $KOH/TiO_2 = 1/1$, synthesizing time 24 hrs, aging time 24 hrs and calcination temperature of TEX>$900^{\circ}C$ for 1 hr, their products were mainly found to be potassium tetratitanate which had thin and long fibres in the range of 10 ~ 20 mm. As the synthesizing time increased and the amount of KOH decreased, potassium tetratitanate was converted into potassium hexatitanate. Also, the length of their fibres became short.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.11 no.4
• /
• pp.1367-1372
• /
• 2010

Copoly(ether-ether-ester)s having flexible side chain were synthesized by polycondensation. Intrinsic viscosities of polymers were between 0.42 and 0.78dl/g in tetrachloroethane. The polymer structures were investigated by $^1H$-NMR and FT-IR, and thermal and liquid crystalline properties of polymers were measured by DSC, TGA, POM and XRD. As results of investigations, synthetic copolymers exhibited lower melting temperature than homopolymers. When the biphenylene units contents in copolymer were more than 60 mol %, nematic mesophase was observed, and the mesophase of synthetic polymers was dependent upon biphenylene content.

• Journal of the Mineralogical Society of Korea
• /
• v.20 no.3
• /
• pp.155-163
• /
• 2007

A novel route to the synthesis of tetramethoxysilane and other silicon alkoxides is described using siliceous mudstone as the raw material. The reaction of amorphous silica with triethanol-amine is enhanced by using an alkali metal hydroxide catalyst to form a range of triethanol-amnine-substituted silatrane species. These can undergo alkoxide exchange in acidic alcohols to form alkoxysilatranes, tetraalkoxysilanes, hexaalkoxydisiloxanes and higher siloxanes. Products were identified by FT-IR spectroscopy, XRD, SEM, 1H and 13C NMR spectroscopy, or gas chromatography.

• Journal of the Korean Chemical Society
• /
• v.40 no.10
• /
• pp.656-662
• /
• 1996

Using low temperature and atmospheric pressure method, we synthesized Na, TPA-ZSM-5 with Si/Al ratio of about 100. We employed 27Al and 29Si MAS NMR spectroscopy and FT-IR to investigate the crystallization process as a function of time. The chemical shift depends on the initial composition of reactants and changes during the course of synthesis different from those reported by others earlier. However, the chemical shift of our final product showed in the range of typical ZSM-5. And the defect site was removed by the calcine. From XRD and SEM data, the formation of ZSM-5 was also confirmed.

• Korean Chemical Engineering Research
• /
• v.51 no.3
• /
• pp.364-369
• /
• 2013

Oxidative dehydrogenation of n-butane over mesoporous Cr catalysts were studied. Catalysts were prepared by Cr impregnated method over Ti or Zr dispersed mesoporous support such as SBA-15, ${\gamma}$-alumina and characterized by XRD, SEM, TEM, FT-IR UV-Vis and ICP-AES. The effect of high surface area was not noticed appreciably in terms of conversion, but for Cr catalysts with Ti and Zr-incorporated on SBA-15 and ${\gamma}$-alumina. showed high selectivity of trans-2-butene.