• Journal of the Korea Institute of Building Construction
• /
• v.23 no.3
• /
• pp.221-229
• /
• 2023

This research aimed to conduct an empirical assessment of the penetration of chloride and sulfate ions into mortar sections using an anion exchange membrane(AEM) and laser-induced breakdown spectroscopy(LIBS). The study involved a simultaneous ion chromatography(IC) analysis and LIBS analysis performed on mortars immersed in varying concentrations of chloride and sulfate. The findings revealed that at the wavelengths specific to Chloride(837.59nm) and Sulfur(921.30nm), the LIBS intensity achieved using AEM surpassed that obtained with a paper substrate at equivalent penetration concentrations. A robust correlation was confirmed between LIBS intensity and chloride ion concentration. Furthermore, when juxtaposed with IC analysis concentration outcomes at identical depths, the AEM displayed a higher intensity. The research noted an enhancement in LIBS intensity and a diminution in errors within the low-concentration section when deploying AEM. However, for the Sulfur wavelength of 921.3nm, there remains a need to augment the sensitivity of the LIBS signal within the low-concentration section in future studies. The findings underscore the potential of employing AEM and LIBS for precise analysis of chloride and sulfate ion penetration into mortar sections. This strategy can aid in bolstering assessment precision and mitigating errors, particularly in regions with low concentrations. It is recommended to further research and develop methods to amplify the sensitivity of the LIBS signal for sulfur detection in low-concentration sections. In sum, the study accentuates the significance of employing advanced techniques like AEM and LIBS for efficacious and precise analysis in the domain of mortar section assessment.

• Environmental Mutagens and Carcinogens
• /
• v.11 no.2
• /
• pp.99-106
• /
• 1991

Facilitated transport of lipophilic benzo(a)pyrene into human fibroblast cells by low density lipoproteins (LDL) was examined. Amounts of [3H]-labeled B(a)P taken up by the Hep 2 fibroblast was increased 3 folds by the addition of LDL (100ng of protein/105 cells) in the media. However, we have found that the facilitated B(a)P transport into cells were diminished by the addition of LDL of which the apoproteins were modified by copper(II) ion-catalyzed oxidation in 10nM copper sulfate. The results of the present study suggest that lipophilic compounds are taken up via adsorptive endocytosis which is mediated by interactions between apoproteins on LDL.

• Applied Chemistry for Engineering
• /
• v.8 no.4
• /
• pp.645-652
• /
• 1997

Electrochemical characteristics and kinetic parameters of copper ion reduction were investigated with a platinum rotating disk electrode (RDE) in a diffusion controlled region. Reduction of Cu(II) in sulfate had one-step two-xelectron process, while the reduction of Cu(II) in chloride solution was involved two one-electron processes. The transfer coefficient of Cu(II) in sulfate solution was lowest, and the transfer coefficient of Cu(I) in halide solutions had the value of nearly one. In chloride solutions, electrodeposition rate of Cu(II) was about one hundred times faster than Cu(I). Diffusion coefficient increased in the order of Cu(II) in chloride solution, Cu(I) in the iodide, bromide, chloride solution, Cu(II) in sulfate solution. The calculated ionic radii and activation energy for diffusion decreased in the same order as above. Morphological study on the copper electrodeposition indicated that the electrode surface became rougher as both concentration and reduction potential increases, and the roughness of the surface was analyzed with UV/VIS spectrophotometer.

• Applied Chemistry for Engineering
• /
• v.21 no.1
• /
• pp.24-28
• /
• 2010

Since the reaction of mineral fixation proceeds with a very slow rate, the pretreatment method to increases the rate of carbonation reaction should be required. To increase the reactivity of serpentine with $CO_{2}$, two pretreatment methods are performed in this study. The heat treatment is done at $630^{\circ}C$. A heat-treated serpentine shows that the strength of -OH has a lower peak in FT-IR spectrum. Chemical pretreatment is the method of leaching of magnesium from serpentine using sulfuric acid at $75^{\circ}C$ for 1 h. Because the protonation of the oxygen atoms polarizes and weakens the Mg-O-Si bond, the removal of magnesium atoms from the crystal lattice was facilitated. After performing the pre-treatment of serpentine, $CO_{2}$ fixation experiments are performed with treated serpentine in the batch reactor. Heat-treated serpentine is converted into 43% magnesite conversion, whereas untreated serpentine has 27% of magnesite conversion. Although the results of the heat-pretreatment are encouraging, this method is prohibited due to excessive energy consumption. Furthermore chemical pretreatment serpentine routes have been proposed in an effort to avoid the cost prohibitive heat pretreatment, in which the carbonation reaction was conducted at 45 atm and $25^{\circ}C$. Chemical-treated serpentine, in particularly is corresponded to a conversion of 42% of magnesite compared to 24% for the un-treated serpentine.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.12
• /
• pp.8665-8672
• /
• 2015

In this study, to investigate the feasibility of malodorous substance and organic matter removal by digest sludge in sewage treatment plants, ammonia, methyl mercaptan(MMC), and hydrogen sulfide($H_2S$) in a reactor submerged with BIO-CLOD(BIO-CLOD) and a reactor not submerged with BIO-CLOD(Non BIO-CLOD) were measured at 24 hours, 48 hours, and 72 hours after the submergence of BIO-CLOD. Whereas the reactor in which BIO-CLOD was submerged showed an ammonia removal rate of 48% and high $H_2S$ and MMC removal rates exceeding 98% in 24 hours, the reactor in which BIO-CLOD was not submerged showed an ammonia removal rate of 45%, an $H_2S$ removal rate of 71%, and an MMC removal rate of 84% in 24 hours indicating the possibility of removal of malodor using BIO-CLOD. A nitrification was shown in which ammonia concentrations decreased over time while nitrate nitrogen concentrations increased and sulfur based malodor components were oxidation decomposed indicating that BIO-CLOD had effects to increase sulfate concentrations in the solution and that sulfate concentration increases and atmospheric $H_2S$ removal rates were correlated with each other. With regard to decreases in organic matter in reactor effluents, BIO-CLOD did not affect in a short period of time and when reactors were operated with HRT 12 hours and HRT 24 hours, HRT 12 hours was considered desirable in terms of economy.

• Applied Chemistry for Engineering
• /
• v.8 no.4
• /
• pp.624-630
• /
• 1997

Zeolite A helps an increase of detergency performance according to showing the ion exchange effect for polyvalant ions and it's detergency performance could be calculated quantitatively by using the disperse stabilization theory because it is water-insoluble material and is as colloid particles in aqueous solution. In this study, zeta potential of carbon black, cellulose, and Zeolite A were measured in each inorganic salt solutions and applied to the theory of Heterocoagulation in order to evaluate the detergency performance of Zeolite A about the particulate soil at the view point of interaction potential energy. Zeolite A was shown help an increase of detergency performance according to the increasing of the steric repulsion between Zeolite A and cellulose in $Na2CO_3$ solution and the decrease of re-deposition of carbon black on the fabric by rapid coagulation with carbon black in $Na_2SO_4$ solution.

• Economic and Environmental Geology
• /
• v.53 no.1
• /
• pp.1-9
• /
• 2020

Magnesium silicate minerals such as serpentine [Mg₃Si₂O₅(OH)₄] have a high potential for the sequestration of CO₂; thus, their reactivity toward dissolution under CO₂-free and CO₂-containing conditions in acidic solvents is a critical process with respect to their carbonation reactions. To examine the carbonation efficiency and dissolution mechanism of serpentine, hydrothermal treatment was performed to the starting material via a modified direct aqueous carbonation process at 100 and 150℃. The serpentine dissolution experiments were conducted in H₂SO₄ solution with concentration range of 0.3-1 M and at a CO₂ partial pressure of 3 MPa. The initial pH of the solution was adjusted to 13 for the carbonation process. Under CO₂-free and CO₂-containing conditions, the carbonation efficiency increased in proportion to the concentration of H₂SO₄ and the reaction temperature. The leaching rate under CO₂-containing conditions was higher than that under CO₂-free conditions. This suggests that shows the presence of CO₂ affects the carbonation reaction. The leaching and carbonation efficiencies at 150℃ in 1 M H₂SO₄ solution under CO₂-containing conditions were 85 and 84%, respectively. The dissolution rate of Mg was higher than that of Si, such that the Mg : Si ratio of the reacted serpentine decreased from the inner part (approximately 1.5) to the outer part (less than 0.1). The resultant silica-rich layer of the reaction product ultimately changed through the Mg-depleted skeletal phase and the pseudo-serpentine phase to the amorphous silica phase. A passivating silica layer was not observed on the outer surface of the reacted serpentine.

• Journal of the Korean Chemical Society
• /
• v.43 no.1
• /
• pp.23-29
• /
• 1999

The Al oxide layer formed in 1M $H_2SO_4$ solution and the influence of applied frequency for electrodeposition of Mn on Al oxide layer were characterized using by impedance spectroscopy. Mn compounds were electrodeposited at the base of pores during deposition with applied low frequency voltage. For the Mn deposited oxide layer at 6OHz and 5Hz in 1 g/L $KMnO_4$ solution, in equivalent circuit for interpretation, the resistance ($R_2$) and capacitance ($C_2$) were considered to be due to deposition of Mn on base of pore. The electrochemical behavior of barrier layer and porous oxide layer on Al have been characterized by capacitance ($C_b$) and Young capacitance ($C_Y$) in equivalent circuit model.

• Economic and Environmental Geology
• /
• v.36 no.2
• /
• pp.103-109
• /
• 2003

The mineralogy of material left after evaporation of acid mine drainage water is generally dependent on the chemical composition of the source water. The residues formed by the evaporation of acid mine water in the Dong-hae coal mine area consists mainly of gypsum (CaSO$_4${\circ}$2$H_2O$) with mine. amounts of alunogen (Al$_2$(SO$_4$)$_3$${\circ}$17$H_2O$) and hexahydrite (MgSO$_4$${\circ}$<.TEX>6$H_2O$). Gypsum was identified from both of the bottom precipitates and the evaporation residues of acid mine water. Alunogen, an aluminum sulfate hydrate, was also formed by evaporation and occurred as needle-like crystals. Aluminum is derived from chemical dissolution of alumine-silicate mineral such as pyre-phyllite, illite and chlorite in wasted rocks. Hexahydrite in evaporation residues occured as needle-like, fibrous, and acicular crystals and was associated with gypsum and alunogen.

• Journal of Conservation Science
• /
• v.12 no.1 s.15
• /
• pp.15-25
• /
• 2003

It is well known that the salt in stoneworks impact on damage of stone by various methods. Various kind of salt is detected in high content in the black surface layer of stone monuments and it is required about origin and roles of salts on blackening to considerate. In this study have been investigated the characteristics of salt in the black crust of sandstone and limestone which used in historical monuments in Berlin, Germany. Salt was analyzed for cation by Atomic Absorption and Atomic Emission Spectroscopy and for anion by ion Chromatograph. The representative ions are $Ca^{2+}\;and\;SO_4^{-2}$ in all samples and the most obvious combinations was proved in calcium sulfate by statistical methods. Because gypsum was detected by X-ray diffraction analyses in the black crusts, this calcium sulfate was confirmed by 2 hydrate type. The probable origin of Ca is air particle in atmosphere around sandstone and calcite in mother rock in limestone, and that of S is polluted air and mortar which used as conservation works.