• Journal of Conservation Science
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• v.37 no.2
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• pp.179-189
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• 2021

In this study, the research objects are gilt plated silver-iron nails excavated from the west of the tombs in Neungsan-ri, Buyeo. A gilt plated silver-iron nail was fabricated by combining silver and iron via heating and then gilding amalgam on top of this combination, demonstrating that this ancient artifact that can be replicated using current technology. Since the metal (Au, Ag) surface of these gilt plated artifacts are covered with iron oxide, which slips into the cracks and scratches of the artifacts as well, desalination is essential. Based on the results of the preliminary experiment, the research objects were classified into grades A, B, and C, according to the degree of corrosion and then desalinated using an alkali solution (NaOH, Sodium Sesquicarbonate of 0.1 M) at 60℃. The results demonstrate that the more serious is the degree of corrosion, the more is the amount of Cl^- detected. Further, more Cl^- was released when NaOH was used than when sodium sesquicarbonate was used, for all grades except Grade A. Furthermore, the more serious is the degree of corrosion, the longer is the desalination period and the reaction with NaOH for all grades except Grade A. A comparison of the Fe composition of the surface before and after desalination shows that Fe composition is the use of NaOH resulted in a smaller increase compared with the use of sodium sesquicarbonate, for all grades except Grade B. However, four of the nails were damaged owing to NaOH (Grade B 3ea, Grade C 1ea) during desalination. Thus, Cl^- ions are more stably released when sodium sesquicarbonate is used than when NaOH is used.

• Applied Chemistry for Engineering
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• v.21 no.1
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• pp.87-92
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• 2010

Desalination experiments were carried out with two types of cell configuration; a CDI cell constructed with carbon electrodes only and a membrane capacitive deionization (MCDI) cell having a cation-exchange membrane on the cathode surface. The salt removal rate and desalination efficiencies increased linearly with increasing the cell potential. Although the same carbon electrodes were used in the desalination experiments, the MCDI cell showed higher salt removal efficiency than that of the CDI cell. The amount of salt removal for the MCDI cell was enhanced by 33.1~135% compared to the CDI cell, depending on the applied cell potential in the range of 0.8~1.2 V. In addition, the current efficiency for the MCDI cell was about 80%, whereas the efficiency was under 40% for the CDI cell. The higher salt removal efficiency in the MCDI cell was attributed to the fact that ions were selectively transported between the electric double layer and the bulk solution in the MCDI cell configuration.

• Resources Recycling
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• v.10 no.3
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• pp.60-65
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• 2001

The PVC powder was treated at $200~250^{\circ}C$, in 0~2 M NaOH solutions for 0~5 h to study the kinetics of dehydrochlorination. In the case of water, the dehydrochlorination of PVC powder proceeded by the zero order reaction with X(the degree of dehydrochlorination), and the apparent activation energy was about 46 kcal/mol. The rate of dehydrochlorination increased with con-centration to 0.5 M NaOH, and proceeded by the first order reaction with X. And, the kinetics of dehydrochlorination was almost equal above 0.5 M NaOH. The apparent activation energies of dehydrochlorination in 0.1 M and 0.5 M NaOH was about 46 kcal/mol, respectively.

• KSBB Journal
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• v.11 no.2
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• pp.211-217
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• 1996

Batch experiments were conducted to investigate the effect of electron donor on reductive dechlorination of 2,4,5-trichlorophenol by a methanogenic consortium. The methanogenic consortium was obtained from the anaerobic digester of a municipal wastewater treatment plant. The batch reactor containing methanogenic consortium was spiked with 2,4,6-trichlorophenol at 10 mg/$\ell$. Acetate, ethanol, glucose of methanol, each was added as an electron donor for methanogenic consortium. During the course of the experiments liquid samples were taken from the batch reactor to measure dechlorination rate and find the dechlorination pathway of 2,4,6-trichlorophenol. After incubation 2,4,6-trichlorophenol was first dechlorinated to 2,4-dichlorophenol and then to 4-chlorophenol. Phenol was not detected in the batch reactor the highest rate of dechlorination of 2,4,6-trichlorophenol was observed when ethanol was used as an electron donor.

• Journal of Conservation Science
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• v.26 no.2
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• pp.133-142
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• 2010

This paper focused on desalination method for the underwater archaeological ceramics. The desalination method applied in this study takes additional conditions such as the amount of desalting water, temperature, and agitation conditions and compares the effects of desalt process. The result of efficiency rate appears that the twenty-times of the object weight of desalting water is more effective than that of ten-times one, but shows less economic compared to the cost. In addition, the research shows that the efficiency rate has been improved around 20 to 30 %, yet such improvement is not taken into account as an effective result considering the risk of damage from the physical and chemical impact and the consumption of energy in applying additional method.

• Journal of Soil and Groundwater Environment
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• v.11 no.2
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• pp.22-37
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• 2006

The applicability of biobarrier or in situ microbial filter technology for the remediation of groundwater contaminated with chlorinated solvent was investigated through batch microcosm study. The efficiency and rates of reductive dechlorination of tetrachloroethylene (PCE) are known to be highly dependent on hydrogen concentration. In this study, the effect of electron donors on the reductive dechlorination of PCE was investigated using vermicompost (or worm casting) and peat as a biobarrier medium. The effect of organic acids (lactate, butyrate and benzoate), yeast extract and vitamin $B_{12}$ on the reductive dechlorination was investigated. In the absence of biobarrier medium (adsorbent), addition of electron donors stimulated the dechlorination rate of PCE compared to the control experiment (i.e., no electron donor added). Among the treatments, addition of lactate or lactate/benzoate as hydrogen donor exhibited the highest dechlorination rate ($k_1=0.0260{\sim}0.0266\;day^{-1}$). In case of using vermicompost as a biobarrier medium, amendment of lactate/benzoate exhibited the highest dechlorination rate following with a pseudo-first-order degradation rate constant of $k_1=0.0849\;day^{-1}$. In contrast, when Pahokee peat was used as a biobarrier medium, either butyrate or lactate addition exhibited the highest dechlorination rate with $k_1$ values of 0.1092 and $0.1067\;day^{-1}$, respectively. The results of this study showed the potential applicability of in situ biobarrier technology using vermicompost or peat as a barrier material for the remediation of groundwater contaminated with chlorinated solvent.

• The Korean Journal of Food And Nutrition
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• v.10 no.4
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• pp.439-445
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• 1997

Radish roots were salted in 4 different salt concentrations (5, 10, 15, 20%) for 3 months followed by desalting. The effects of desalting process on salt concentration, Ca content, texture and sensory characteristics were investigated during 3 days of desalting period at $25^{\circ}C$. NaCl content in danmuji salted in lower NaCl concentrations decreased rapidly and a linear relationship was found between the decrease in NaCl content and the logarithmic value of desalting time. Changes in Ca content of danmuji also exhibited a similar trend to that of NaCl content. Hardness of radish root tended to increase wit an increase in desalting time up to 2 days of desalting and then decreased slightly at the 3rd day of desalting. The results of sensory evaluation revealed that regardless of salt concentration used acidic, salty odor and taste of danmuji decreased significantly during desalting, however, there was very little change in yeast-moldy odor and taste with the intensity being very low in danmuji salted in higher salt concentrations. Among the textural properties, the crispness of danmuji salted in 5, 10 and 20% NaCl concentrations increased up to 2 days of desalting and decreased slightly thereafter, whereas that of radish salted in 15% NaCl concentration increase continously during 3 days of desalting. Total acceptibility was best in danmuji salted in 20% NaCl concentration and desalted for 3 days.

• Journal of Soil and Groundwater Environment
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• v.9 no.3
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• pp.49-55
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• 2004

A soil enrichment LYF-1 culture from a contaminated site, which could reductively dechlorinate 900 $\mu$M (ca. 150 mg/L) of tetrachloroethylene (PCE) stoichimetrically into cis-1,2-dichloroethylene (cis-DCE), was established and characterized. The enrichment culture can use yeast extract, peptone, formate, acetate, lactate, pyruvate, citrate, succinate, glucose, sucrose, and ethanol as electron donors for dechlorination of PCE. Addition of NO$_2$$^{[-10]}$ and NO$_3$$^{[-10]}$ as alternative electron acceptors showed complete inhibition of PCE dechlorination, but S$_2$O$_3$$^{-2}$ , SO$_3$$^{-2}$ and SO$_4$$^{-2}$ had no significant effect on PCE dechlorination. The enrichment culture was attached to ceramic media in an anaerobic fixed-bed reactor. The fixed-bed reactor showed more than 99％ of PCE degradation in the range of PCE loading rate of 0.13-0.78 $\mu$moles/L/hr. The major end product of PCE dechlorination was cis-DCE.

• Food Science and Preservation
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• v.19 no.6
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• pp.893-900
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• 2012

To establish a new manufacturing process of low-salted fermented anchovy sauce, commercial fermented anchovy sauce with 23% NaCl was desalted using a spirit. The proximate composition, total nitrogen, amino nitrogen, Escherichia coli, and total and free amino acid contents were analyzed to evaluate the quality characteristics of commercial salted fermented anchovy sauce (CFAS) and low-salt fermented anchovy sauce by desalting processing (LFAS). The salinity of saltwater and fermented anchovy sauce decreased with an increase in the spirit added to 23% NaCl saltwater and 23% NaCl commercial fermented anchovy sauce. The total nitrogen and amino nitrogen contents were higher in LFAS than in CFAS. The major amino acids that were commonly found in CFAS and LFAS were glutamic acid, alanine, lysine and leucine. Basic data were provided for commodification research on low-salt fermented anchovy sauce, which is very important for the diet of humans.

• Resources Recycling
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• v.10 no.6
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• pp.3-8
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• 2001

This study was examed about leaching behavior in order to separate plasticizer selectively before dechlorination from flexible PVC material in alkali solutions at $80~120^{\circ}C$. The dechlorination of that was not almost occurred below $100^{\circ}C$. But the yield of elution of plasticizer was 100% above 5M NaOH. Therefore, by controlling alkali concentration and reaction temperature, it is possible to extract the plasticizer selectively without taking dechlorination.