• Applied Chemistry for Engineering
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• v.31 no.3
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• pp.317-322
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• 2020

Hydroxylammonium nitrate (HAN; NH₃OHNO₃) is an ionic energy material having a low melting temperature and vapor pressure with a high oxygen balance. To utilize it as an oxidizer for a high content liquid mono-propellant, a dual solvent was used to obtain HAN in a solid particulate form. The dehydrated crystal from an aqueous HAN was washed with dual organic solvents including acetone and ethanol, finally resulting in the moisture content of 13.8 wt%. When acetone was applied as a single solvent, the maximum synthesis yield of 88%, the HAN content evaluated by TGA of 86.2%, and the decomposition temperature ranged 160℃ to 205℃ were achieved.

• Preventive Nutrition and Food Science
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• v.22 no.2
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• pp.107-117
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• 2017

The purpose of this study was to evaluate the antioxidant and anticholinesterase activities of yellow and white bitter yams from South Western Nigeria using methanolic extraction and simulated gastrointestinal digestion models. The phenolic compounds in the bitter yam varieties were evaluated by high performance liquid chromatography with a diode array detector (HPLC-DAD). The total phenolic content of the bitter yams was measured by the Folin-Ciocalteu method, reductive potential by assessing the ability of the bitter yam to reduce $FeCl_3$ solution, and the antioxidant activities were determined by the 2,2-diphenyl-1-picrylhydrazyl radical ($DPPH^{\cdot}$) scavenging activity, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation ($ABTS^{{\cdot}+}$) scavenging activity, nitric oxide radical ($NO^{\cdot}$) scavenging ability, hydroxyl radical scavenging ability, and ability to inhibit $Fe^{2+}$-induced lipid oxidation. The HPLC-DAD analysis revealed the presence of some phenolic compounds in the studied bitter yam varieties, with varying degree of quantitative changes after cooking. The antioxidant indices (total phenolic content, total flavonoid content, reducing power, $DPPH^{\cdot}$ scavenging activity, $ABTS^{{\cdot}+}$ scavenging activity, and $NO^{\cdot}$ scavenging activity) were higher in the simulated gastrointestinal digestion model compared to the methanolic extract, with the in vitro digested cooked white bitter yam ranking higher. Similarly, the in vitro digested yams had a higher inhibitory action against lipid oxidation compared to the methanolic extracts, with the cooked white bitter yam ranking high. The methanolic extracts and in vitro enzyme digests showed no acetylcholinesterase inhibitory abilities, while methanolic extracts and the in vitro enzyme digest displayed some level of butyrylcholinesterase inhibitory activities. Therefore the studied bitter yams could be considered as possible health supplements.

• Environmental Engineering Research
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• v.25 no.3
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• pp.335-344
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• 2020

This work describes highly efficient recovery and selective leaching of Zn from electric arc furnace dust (EAFD) with different physicochemical properties, induced by acid leaching at ambient conditions. The chemical compositions, mineralogical phases, and particle sizes of the EAFDs were analyzed and compared. The effects of leaching time, liquid/solid ratio, acid type, and acid concentration on the selective leaching of Zn were also studied. The EAFD with high Fe/Zn ratio (> 1, EAFD₃) was richer in ZnFe₂O₄ and exhibited larger particle size than samples with low Fe/Zn ratio (< 1, EAFD_1,2). ANOVA analysis revealed that the Fe/Zn ratios of the EAFDs also have a significant effect on Zn extraction (p < 0.005). Selective leaching of Zn with minimum Fe dissolution was obtained at pH > 4.5, regardless of other parameters or sample properties. The maximum Zn extraction rate obtained by the pH control was over 97% for EAFD₁ and EAFD₂, 76% for EAFD₃, and 80% for EAFD₄. The present results confirm that the Fe/Zn ratio can be used to identify EAFDs that permits facile and high-yield Zn recovery, and pH can be used as a process control factor for selective leaching of Zn regardless of any differences in the properties of the EAFD sample.

• Korean Journal of Materials Research
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• v.15 no.1
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• pp.31-36
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• 2005

It is well known that PCB (Printed Circuit Board) is a complex mixture of various metals mixed with various types of plastics and ceramics. In this study, high temperature pyre-metallurgical process was investigated to extract valuable metallic components from the PCB scrap. For this purpose, PCB scrap was shredded and oxidized to remove plastic materials, and then, quantitative analyses were made. After the oxidation of the PCB scrap, $30.6wt\%SiO_2,\;19.3wt\%Al_2O_3\;and\;14wt{\%}CaO$ were analyzed as major oxides, and thereafter, a typical composition of $32wt\%SiO_2-20wt\%Al_2O_3-38wt{\%}CaO-10wt\%MgO$ was chosen as a basic slag system for the separation of metallic components. Moreover a size effect of crushed PCB scrap was also investigated. During experiments a high frequency induction furnace was used to melt and separate metallic components. As a result, it was found that the size of oxidized PCB scrap was needed to be less 0.9 m to make a homogeneous liquid slag and to recycle metallic components over $95\%$.

• Journal of Soil and Groundwater Environment
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• v.19 no.4
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• pp.45-51
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• 2014

In accordance with the view on remediated soil as a resource, this study assessed the applicability of soil washing with the neutral phosphate for remediation of arsenic (As)-contaminated soil. Three soil samples of different land uses (i.e., rice paddy, upland field and forest land) were collected from the study site, and the aqua regia-extractable As concentrations were 59.2, 30.8 and 53.1 mg/kg, respectively. Among the neutral phosphate reagents, ammonium phosphate showed the highest As washing efficiency. The optimized washing condition was 2-hr washing with 0.5M ammonium phosphate solution (pH 6) and soil to liquid ratio of 1 : 5. The extraction efficiencies of As did not guarantee the residual soil As concentrations to satisfy the Korea soil regulatory level (i.e., Worrisome level) in the three soil samples. To enhance washing efficiency, the As-contaminated soil was submerged in washing solution (1 : 1, w/v) for 24 hr and 1-hr washing with 0.5M ammonium phosphate solution was tested. As extraction efficiencies of 36.1 (rice paddy), 21.4 (upland field) and 26.4% (forest land) were attained, which satisfied the Worrisome level for Region 1 (25 mg/kg of As) in rice paddy, but not in upland field and forest land.

• The Journal of Internal Korean Medicine
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• v.40 no.3
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• pp.331-342
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• 2019

Objectives: Samul-tang is commonly used to alleviate the side effects of chemotherapy. This study aimed to establish an efficient method of extracting ACTS002 based on Samul-tang using the yield, high-performance liquid chromatography (HPLC), and antioxidant assay. Methods: ACTS002 was extracted from each extraction solvent, and the contents of 5-hydroxymethyl-2-furaldehyde (5-HMF), paeoniflorin, and ferulic acid were quantitatively analyzed and compared using HPLC. Moreover, the antioxidant activities of ACTS002 were measured using total flavonoids, total phenolic compounds, 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), and Ferric reducing/antioxidant power (FRAP). Results: All of the components were set as the index contents because they were easy to process. The antioxidant activity of total flavonoids was the highest in 70% ethyl alcohol extracts, and total phenolic compounds were the highest in 50% ethyl alcohol extracts. In DPPH, 50% ethyl alcohol extracts showed the highest activity, and in ABTS 70% ethyl alcohol extracts were the highest. In FRAP, 70% ethyl alcohol extracts showed the highest activity. Conclusions: ACTS002 can control quality by setting 5-HMF, paeoniflorin, and ferulic acid as the index contents. The antioxidant activity measurement was relatively high in the 50% and 70% ethyl alcohol extracts. Our results can predict the possibility of a pharmacological activity and the standardization of ACTS002.

• Mass Spectrometry Letters
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• v.10 no.1
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• pp.38-42
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• 2019

Damaurone D belongs to the genus Rosa and is a traditional medicinal product used for the treatment of depression, inflammation, and infectious diseases. The purpose of this study was to develop a simple liquid chromatography-tandem mass spectrometry method for the detection of damaurone D in rat plasma and to demonstrate its application in pharmacokinetic studies. Damaurone D and berberine (internal standard) were extracted with acetonitrile using a protein precipitation method. Mass transition was monitored in multiple reaction monitoring mode at m/z $323.2{\rightarrow}267.0$ for damaurone D and m/z $336.1{\rightarrow}320.0$ for berberine in positive ion mode. Analytical validation was conducted by evaluating the specificity, linearity, accuracy, precision, matrix effect, extraction recovery, and stability. The calibration curves were linear over 2-1000 ng/mL. The intra- and inter-day precision and accuracy of quality control samples were 4.79-13.33% and 86.23-102.75%, respectively. The matrix effect and extraction recovery were 96.11-98.47% and 96.11-102.25%, respectively. In the pharmacokinetic study after intravenous administration of damaurone D at a dose of 3 mg/kg in rats, the area under the curve and clearance of damaurone D in rat plasma were $16750.26{\pm}2676.10min{\cdot}ng/mL$ and $182.44{\pm}31.36mL/min/kg$, respectively.

• Journal of People, Plants, and Environment
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• v.23 no.5
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• pp.537-544
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• 2020

Background and objective: Artemisia argyi has a long history as an effective treatment for various diseases. The detection of environmental pollutant benzo(a)pyrene, a known human carcinogen, in the leaves of Artemisia argyi is cause for concern. For medicinal plant extracts, both a reduction of benzo(a)pyrene as well as the maintained effectiveness of the compound are important. Therefore, in this study, we propose an optimized process for the addition and filtration of activated carbon to reduce benzo(a)pyrene and change the contents of the indicating substance(jaceosidine and eupatilin). Methods: Artemisia argyi EtOH extract containing 36 ppb of benzo(a)pyrene was added to 0.1, 0.5, 1.0, and 1.5% (w/w) of activated carbon for 120 min and filtered using an activated carbon filter 1, 2, 3, and 5 times respectively. The content of benzo(a)pyrene and indicating substances in Artemisia argyi extract were then measured with high performance liquid chromatography (fluorescence and UV detectors). Results: As the amounts of activated carbon powder and filtering cycles increased, the content of benzo(a)pyrene in the Artemisia argyi extract decreased. However, when activated carbon powder 1.5% was added to the extract, and when the activated carbon filter was filtered five times, the results were reduced by 15% and 30~40% respectively. The optimal extraction condition for reducing benzo(a)pyrene was adding 1.5% of activated carbon powder. This resulted in reducing benzo(a)pyrene by 83% and indicating substances by about 4%. Conclusions: Here we present a process for reducing benzo(a)pyrene in Artemisia argyi extract using activated carbon to reduce toxicity and minimize the loss of active ingredients. This approach has potential application within a manufacturing process of various medicinal plant extracts.

• Journal of the Korean Applied Science and Technology
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• v.40 no.2
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• pp.332-341
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• 2023

The controversy is becoming a hot issue after informed that the water release from Canadian oil sands tailings may initiate within a few years. The surface-mined bitumen extraction in open pit generates wastewater inevitably, which has been conveyed to store in tailings ponds. Currently, the size of tailings pond is getting seriously larger. It is known that tailings treatment is very difficult because the generation of MFT (mature fine tailings) layer is hardly processable. It would be the key process to separate solids and liquid placed within MFT where fine particles are well dispersed. In this paper, the surface-mined bitumen extraction process was first introduced, and followed by presenting the components of tailings as well as the characteristics of MFT. In addition, MFT process options were evaluated. It is expected that successful MFT treatments may be achieved by dewatering process using effective polymer flocculants in near future.

• Analytical Science and Technology
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• v.20 no.5
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• pp.442-447
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• 2007

The properties of garlic (Allium sativum L.) are attributed to organosulfur compounds. In this paper, an analytical technique with a rapid and simple sample preparation procedures for determination of diallyl disulfide (DADS) in garlic was reported. The DADS was simply extracted with various solvents (methanol, benzene or tetrahydrofuran) from garlic and prepared for HPLC analysis. From the results, the methanol was select as an optimal extraction solvent. The mobile phase was composed from methanol and water, and the gradient elution mode was applied. 0.61 mg of DADS per g garlic powder can be extracted with methanol. This work offers some advantages over the currently accepted techniques and would be useful for chemical and biological studies of garlic and its products.