• The Korean Journal of Ceramics
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• v.2 no.2
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• pp.63-69
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• 1996

Barium titanyl oxalates, strontium titanyl oxalates and calcium zirconyl oxalates were prepared with variation of solution concentration and method of adding mixed metal ion solution into oxalic acid. Then they were aged in distilled water, ethanol or methanol, respectively. Barium titanyl oxalates and calcium zironyl oxalates were grown in water and strontium titanyl oxalates were groun in both water and methanol. They were supposed to be grown through the solutionl and reprecipitation mechanism. Nonuniform dispersion of particles in liquid phase is thought to cause abnormal particle growth.

• Korean Journal of Poultry Science
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• v.49 no.4
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• pp.221-228
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• 2022

Major egg white proteins and their hydrolysates serve as functional food ingredients that have certain metal-chelating properties. Employing egg white proteins and their hydrolysates to scavenge dietary oxalates is anticipated to have beneficial effect in the prevention of kidney stones. The objective of this study was to determine the biogenic oxalate-chelating activity of ovalbumin, ovomucin, and ovotransferrin and their hydrolysates. To prepare oxalate extracts, 30 mL of 0.25 N HCl was added to separately to 0.5 g of dried spinach and starfruit powders followed by boiling for 15 min, and after cooling, the addition of a further 20 mL of 0.25 N HCl. Having prepared these extracts, ovalbumin, ovomucin, and ovotransferrin and their hydrolysates were separately mixed with oxalate extracts and incubated at 3℃ for 24 h. Following centrifugation, supernatants were analyzed by HPLC using a reverse-phase C18 column coupled with a diode array detector. We found that all assessed proteins and their hydrolysates showed biogenic oxalate-chelating activity against the oxalates of spinach. In contrast, however, only ovalbumin, ovalbumin-hydrolysate, and ovomucin showed chelating activity (57.10%±8.84%, 85.44%±5.30%, 73.20%±4.13%, respectively) against the oxalates of starfruit (P<0.05). Overall, hydrolyzed ovalbumin was identified as the most effective chelator of the oxalates both spinach and starfruit. In this study, we thus established that the assessed egg white proteins and their hydrolysates have oxalate-chelating activity in vitro, thereby indicating that these compounds have potential utility as nutraceuticals for the chelation of dietary oxalate. However, further research will be necessary to verify their oxalate-chelating activities against different fruits and vegetables and under specific in vivo conditions and against purified oxalate.

• Food Science and Biotechnology
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• v.16 no.4
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• pp.650-654
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• 2007

Many vegetables contain oxalate at various levels depending on their type and family. Oxalate is known to reduce mineral bioavailability from foods. The following study was conducted to determine soluble and total oxalate contents in 32 plant samples commonly consumed in Korea using high-performance liquid chromatography (HPLC). Chard, amaranth, and spinach contained total oxalate of >1,000 mg/100 g. Approximately 45% of the oxalate in amaranth is insoluble, whereas 74.46 and 92.45% of the oxalates in chard and spinach, respectively, was soluble oxalates, which may be removed by blanching. Eggplant, carrot, leak, ginger root, spinach, burdock, and sweet pepper contained more than 90% soluble oxalate in total oxalate content. However, all oxalates detected in lettuce and celery were insoluble. Oxalate was not detected in shepherd's purse, bellflower root, garlic, radish root, broccoli, cabbage, onion, lotus root, adlay, cucumber, kale, and pumpkin. These observations provide useful information needed for selection of vegetables.

• Journal of Ocean Engineering and Technology
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• v.14 no.1
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• pp.37-43
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• 2000

$PbTiO_3$ was prepared by addition of lead-tltanium mixed aqueous solution to an ethanol solution of oxalic acid. The influence of various ripening factors was invesigated. On the basis of the results in the mono-component system we studied the foramtion of $PbTiO_3$ phase with various ripening conditions. The $PbTiO_3$ phase formation was accelerated with the ripening time temperature and ultrasonic irradiation.

• Journal of the Korean Ceramic Society
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• v.20 no.2
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• pp.107-114
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• 1983

Formation of Strontium titanate from the products of coprecipitation takes place at 110$0^{\circ}C$ which is 200-30$0^{\circ}C$ lower than that from mechanical mixtures of $SrCO_3$ and $TiO_2$. This is apparently due to the nature of the compounds formed by the reaction of mixtures of aqueous solutions of $SrCl_2$ and $TiCl_4$ with an ammoniacal solution of ammoni-um carbonate and ammonium hydroxide. A procedure is described for preparing strontium titanyl oxalate tetrahydrate in the several mole ratio of $TiCl_4$ to $SrCl_2$. STrontium titanyl oxalates decompose to titanate at elevated temperature. The coprecipitates and the fired specimen were subjected to examined thermal and X-ray analyses and microstruc-ture by SEM.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2017.05a
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• pp.338-339
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• 2017

• Journal of the Korean Wood Science and Technology
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• v.26 no.1
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• pp.57-62
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• 1998

In this research, the removal or uptake of heavy metals such as coppers by using oxalic acid metabolism of wood rot fungi, Tyromyces palustris were endeavored. As results, the addition of oxalic acid to copper containing culture did not cause the mycelium growth, but Tyromyces palustris was able to grow in this culture without inhibition. Tyromyces palustris grew with the cicular halo type in copper containing culture, and this type was formed as collectives after examining by microscope, and considered as copper oxalates by analyzing FT-IR comparison experiment with standards. According to this result, Tyromyces palustris has secreted oxalic acid during incubation, this secreted oxalic acid was combined with coppers, and formed copper oxalates by chelating reactions. In other words, the oxalic acid was might be as non-toxifying agent of coppers in medium. By using this copper removal mechanisms, Tyromyces palustris immobilized sawdust was used in bench scale air lift system for removing coppers. The added coppers were almost removed from the system within 72hrs. Therefore, this nonenzymatic wood degradation mechanism may give a possibility for removing coppers from copper containing waste water.

• Journal of the Korean Chemical Society
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• v.54 no.5
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• pp.603-610
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• 2010

The potential feasibility of Maghnia clay as adsorbent to remove three cationic dyes (methylene blue (MB), neutral red (NR) and malachite green oxalates (MG)) from aqueous solution was investigated at various operating parameters such as contact time, pH, initial dye concentration and adsorbent dose. Optimum pH values for dyes adsorption were 6 for NR and 7 for MB and MG, respectively. Maximum adsorption of dyes, i.e. $\geq$ 90% has been achieved in aqueous solutions in 60 minutes. The adsorption of dyes followed the pseudo-second-order rate equation.

• The Korean Journal of Ceramics
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• v.2 no.2
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• pp.70-75
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• 1996

On the basis of growth mechanism proposed by recent work, partile of barium titanyl oxalate was controlled by aging in water. From aging at $25^{\circ}C$ for 3 hours, uniform particles of 0.3 ${\mu}$m were obtained. During aging, abnormal particle growth was observed, which were thought to be caused by impurities in water. With increase of aging time and temperature, particle grows more, and differential growth was promoted. In aging for long time, grown particles were cracked.

• Journal of the Korean Chemical Society
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• v.55 no.2
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• pp.208-217
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• 2011

The effects of pH and temperature on the removal of two dyes (neutral red; NR and malachite green oxalates; MG) from aqueous effluents using Maghnia montmorillonite clay in a batch adsorption process were investigated. The results showed the stability of the optical properties of MG in aqueous solution and adsorbed onto clay under wide range of pH 3-9. However, the interaction of NR dye with clay is accompanied by a red shift of the main absorption bands of monomer cations under pH range of 3-5, whereas, those of neutral form remains nearly constant over the pH range of 8-12. The optimal pH for favorable adsorption of the dyes, i.e. ${\geq}$90% has been achieved in aqueous solutions at 6 and 7 for NR and VM respectively. The most suitable adsorption temperatures were 298 and 318 K with maximum adsorption capacities of 465.13mg/g for NR and 459.89 mg/g for MG. The adsorption equilibrium results for both dyes follow Langmuir, Freundlich isotherms. The numerical values of the mean free energy $E_a$ of 4.472-5.559 kj/mol and 2.000-2.886 kj/mol for NR and MG respectively indicated physical adsorption. Various thermodynamic parameters, such as ${\Delta}H^{\circ}$, ${\Delta}S^{\circ}$, ${\Delta}G^{\circ}$ and Ea have been calculated. The data showed that the adsorption process is spontaneous and endothermic. The sticking probability model was further used to assess the potential feasibility of the clay mineral as an alternative adsorbent for organic ion pollutants in aqueous solution.