• 한국세라믹학회지
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• 제29권12호
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• pp.963-969
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• 1992

This paper describes the feasibility for a direct production of zinc oxalate powders from zinc-loaded D2EHPA solutions combining the purification and the precipitation in one operation unit. This process has the potential as an alternative to conventional method for the synthesis of zinc oxide precursor particles from the hydrometal-lurgical processes. Zinc was extracted into D2EHPA in kerosene and then zinc-loaded D2EHPA solution was emulsified with oxalic acid-HCl solution to precipitate zinc oxalate powder, which was readily calcined to zinc oxide. The precipitation kinetics and yield were sensitive to experimental conditions. The morphology, size and size distribution of the zinc oxalate powders varied with zinc/oxalate ion riatio, temperature, and the presence of SPAN 60, which affected nucleation, growth, and the emulsion characteristics.

• 청정기술
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• 제29권1호
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• pp.46-52
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• 2023

옥살산(oxalic acid)은 기존에 질산을 사용한 carbohydrates의 산화 공정에 의해 얻어질 수 있으며 여러 분야에서 사용되고 있다. 하지만 이 반응은 다양한 질소 산화물을 형성하고 많은 증간 생산물의 분리를 필요로 하기에 복잡하고 환경에 유해하다. 한편, 이산화탄소로부터 전기화학적 방법에 의해 옥살산을 높은 효율로 얻을 수 있는 방법이 제안되었다. 아연 전극 산화에 의해 생성된 Zn²⁺이온과 CO₂ 환원에 의한 oxalate이온의 반응으로 zinc oxalate(ZnC₂O₄)가 얻어진다. 이후 산처리에 의해 옥살산이 생성될 수 있으나 강산과 열을 필요로 한다. 본 연구에서는 CO₂의 전기화학적 전환으로 형성된 ZnC₂O₄을 강산을 사용하지 않고, 간단하고 분리가 쉬운 방법을 적용하여 옥살산으로 전환하고자 한다. 또한, 고부가 물질인 글리콜산으로 더 전환시킴으로써 이산화탄소에서 고부가 물질로의 전환 가치를 높이고자 하였다. ZnC₂O₄를 상온, 상압에서 화학적 방법 및 여과 과정을 통해 효과적으로 Zn(OH)₂ 입자와 oxalate 용액으로 분리하였으며 얻어진 Zn(OH)₂와 oxalate는 전기화학적 방법을 사용하여 각각 Zn, 글리콜산으로 전환되었다.

• 한국환경농학회지
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• 제4권1호
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• pp.31-36
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• 1985

현미중(玄米中) 카드뮴, 아연(亞鉛) 및 연(鉛)의 함량추정(含量推定)에 적합(適合)한 토양침출액(土壤浸出液)을 선발(選拔)하여 토양분석치(土壤分析置)를 이용(利用)한 예측모형식(豫測模型式)을 다단계식(多段階式)나으로 분석(分析) 유도(誘導)해 본 결과(結果), 공시(公試)된 침출액(浸出液) 0.1M HCl, 0.1 M $HNO_3$, 0.001M 2Na-EDTA 및 0.1 M $NH_4-oxalate$ 중(中) 현미중(玄米中) 카드뮴과 가장 높은 상관(相關)을 나타낸 침출액(浸出液)은 0.001M 2Na-EDTA였고, 아연(亞鉛)은 0.1N HCl, 연(鉛)은 0.1 M $NH_4-oxalate$였으며 3종김속(種金屬) 모두와 높은 상관정도(相關程度)를 나타낸 침출액(浸出液)은 0.1M $NH_4-oxalate$였다. 또 토양특성(土壤特性)을 이용(利用)한 다중회귀분석결과(多重回歸分析結果) 현미중(玄米中) 카드뮴함양추정(含量推定)에는 pH와 Ca 함양(含量)이 가장 중요(重要)한 변수(變數)로 작용(作用)하였고, 현미중(玄米中) 아은(亞銀)은 CEC 및 Mg 함양(含量)이였으며, 현미중(玄米中) 연함양(鉛含量)은 Na함양(含量)을 제외(除外)한 Ca, CEC, pH, Mg, OM, K등 모든 특성(特性)이 중요(重要)한 변수(變數)였다.

• Korean Chemical Engineering Research
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• 제55권6호
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• pp.785-790
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• 2017

To collect zinc, Fe and Zn in spent pickling solution were extracted by using TBP (tributyl phosphate), and Zn was recovered from extracted solution to zinc oxalate particles by oxalic acid solution. The reusability of TBP solvent was also tested. The distribution coefficient of Zn was not affected by the concentration of Fe in spent pickling solution, almost constant with the values of 7.12~9.31 when extracted by TBP solvent. It was found that the extraction capacity of TBP solvent for Zn is higher than that for Fe. The extraction efficiency of Zn was higher than 95%, while most of Fe was left in aqueous phase. After the recovery, the used TBP solvent could be repeatedly reused for the extraction of Zn up to eight times. XRD analysis showed that zinc oxalate ($ZnC_2O_4$ $2H_2O$) was formed from the reaction of Zn-TBP and oxalic acid. From the results of SEM analysis, the formation of zinc oxalate particle was strongly affected by the concentration of oxalic acid. In summary, Zn in spent pickling solution was successfully separated and recovered with TBP solvent and oxalic acid solution, respectively.

• 한국식품영양과학회지
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• 제38권7호
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• pp.870-878
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• 2009

본 연구는 국산 113종 콩 장려품종의 total oxalate(Ox), phytate($InsP_6$)와 calcium(Ca), magnesium(Mg), sodium (Na), zinc(Zn), potassium(K)을 분석하여 옥살산칼슘 결정생성을 최소화할 수 있는 품종의 선발 및 안전한 콩 가공식품 제조를 위한 자료를 제시하고자 하였다. 113종의 콩 장려품종에서 Ca과 Mg 함량 분포는 각각 $0.586{\sim}3.177$과 $0.559{\sim}3.085\;mg/g$이었으며, Ca는 다올콩은 3.177 mg/g으로 가장 높았고, Mg는 선흑콩은 3.085 mg/g으로 가장 높은 함량을 보였다. Ca과 Mg 사이에서 품종간 유의적인 차이가 나타나지 않았다. Ox와 InsP6 함량 분포는 각각 1.24(선흑콩)$\sim$3.81(다원콩)과 0.43(만리콩)$\sim$4.72(다기콩) mg/g 범위이었고, 옥살산칼슘 결정의 저해물질인 $InsP_6$의 함량이 Ox의 함량보다 상대적으로 높은 함량 분포로 존재하였다. 또한 Ca, Mg, Ox 및 $InsP_6$ 함량 사이의 교차상관관계분석을 통해 Ca과 $InsP_6$ 함량이 Ox 함량보다 높은 선흑콩과 단미2가 옥살산칼슘 생성의 잠재적 위험성을 최소화할 수 있는 품종으로 판단되었다.

• 대한치과보철학회지
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• 제32권2호
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• pp.181-194
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• 1994

The purpose of this study was to compare the retention and fitness of crown treated with various desensitizing agents on natural teeth. Varnish, dentin primer, bonding agent and potassium oxalate treated groups and control group with no treatment were used. The retention test was executed with the Instron test machine(Instron Co.,U.S.A.) on 24 hours after cementation with zinc phosphate cement. After retention test, the teeth and crowns were washed and recemented. The cemented crowns were embedded in clear resin and sectioned with a diamond saw. The occlusal and marginal fitnesses, were measured indirectly with a stereomicroscopic photographs. The result of this study were obtained as follows : 1. The retention of control group was higher than any other desensitizing agent treated group. 2. The differences of retention among varnish, dentin primer, bonding agent and potassium oxalate treated groups were not statistically significant. 3. There were no statistically significant difference in fitness at occlusal surface and margin among control, varnish, dentin primer, bonding agent and potassium oxalate treated groups. According to these results, desensitizing agents used to protect the pulp from irritation of luting agents may adversely affect the retention of castings. Therefore, desensitizing agents should be used in limited areas carefully.

• 한국환경농학회지
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• 제29권2호
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• pp.115-119
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• 2010

Zinc (Zn) is an essential element required for growth and development of plants. However, Zn can be toxic to plants when it presents excessive amount. Phytoextraction is an economic and environment-friendly technique using plants to clean-up metal-contaminated soils. However, the technique cannot be applied in highly metal-contaminated areas because plants will not normally grow in such conditions. Therefore, this research focuses on identifying chelating agents which are biodegradable and applicable to highly metalcontaminated areas. Zn as a target metal and cysteine (Cys), histidine (His), malate, citrate oxalate, succinate, and ethylenediamine (EDA) as biodegradable chelating agents were selected. Plants were grown on agar media containing various chelating agents with Zn to analyze the effect on plant growth. Malate and His slightly increased the inhibitory effect of Zn on root growth of plants, whereas Cys, citrate, oxalate, and succinate did not show significant effects. However, EDA strongly diminished the inhibitory effect of Zn on root growth. The effect of EDA is correlated with decreased Zn uptake into the plants. In conclusion, as biodegradable chelating agents, EDA is a good candidate for growth of plants in highly Zn-contaminated areas.

• 한국환경농학회지
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• 제4권1호
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• pp.25-30
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• 1985

침출액(浸出液)의 종류별(種類別) 토양중(土壤中) Cd, Zn, Pb의 침출성(浸出性) 및 이들 중김속(重金屬)과 토양특성(土壤特性)과의 관계(關係)를 구명(究明)코자 폐아연광산지역(廢亞鉛鑛山地域)의 린근답(隣近畓)에서 채취(採取)한 토양시료(土壤試料) 84점(點)을 사용(使用)하여 0.1M-염산(鹽酸), 0.1M-실산(室酸), 0.001M-ED TA 및 0.1M-수산(修酸)암모늄등(等) 4종(種)의 침출액(浸出液)을 비교분석(比較分析)한 결과(結果) 침출정도(浸出程度)는 0.1 M $HCl{\geq}0.1M-HNO_3> 0.001 M-2Na EDTA>0.1 M NH_4-oxalate$순(順)이였으며 침출액(浸出液)의 pH가 낮을수록 침출력(浸出力)이 강하였다. 또 침출액간(浸出液間) 및 전함량(全含量)과 침출액성(全含量) 중김속(重金屬) 함량간(含量間)에는 고도(高度)의 회귀관계(回歸關係)가 성립(成立)되었으나 침출력(浸出力)이 극히 낮은 0.1 $M-NH_4-oxalate$는 중김속(重金屬) 오염량(汚染量) 식은 토양(土壤)에 대(對)한 작물(作物)의 오염정도추정(汚染程度推定)을 목적(目的)으로 토양(土壤)을 분석(分析)할 경우 적용(適用)하기에는 부적합(不適合)할 것으로 생각되었다. 토양중(土壤中) Cd, Zn 및 Pb는 토양(土壤)의 pH와 정(正)의 상관관계(相關關係)를 가지나 토양유기물(土壤有機物)과 CEC와는 지역간(地域間)에 서로 상반(相反)되는 상관관계(相關關係)를 보였으며 양(陽)이온중 Mg만이 유의성(有意性) 있는 부(負)의 상관관계(相關關係)를 나타냈다.

• 동아시아식생활학회지
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• 제5권2호
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• pp.63-71
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• 1995

Defatted sesame flour is the by-products obtained after oil extracting process. Although this flour has high quality and quantity of protein its use is limited only for animal feed and fertilization. Sesame seeds contain antinutrients such as oxalate, phytate and phenol compounds and these compounds lower their nutritive value. recently, ultrafiltration(UF) has been used to concentrate protein from various food sources. This study was carried out to examine the effects of UF with different membrane pore size on the components of sesame protein concentrates including antinutrients and to compare with that of conventional acid-precipitated sesame protein isolate. The protein contents of sesame protein concentrates prepared by JF using 10K, 30K, 100K were 84.2%, 82.7%, 76.4% and the protein yields were 36.44%, 34.69, 31.43% and the protein contents was 88.7% Alkali extraction process at pH 9.0 followed by UF technique reduced oxalate and phytate content. There were 85% and 94% reduction of oxalate and phytate content by UF with membrane pore size of 100K daltons, respectively. However, the content of total phenol compounds was not reduced by this method. About 99% of calcium and 50% of zinc were removed by UF with membrane of 100K daltons. total essential amino acid contents of sesame protein concentrates prepared by UF were decreased slightly when compared with acid-precipitated sesame protein concentrate.

• Advances in nano research
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• 제14권4호
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• pp.313-327
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• 2023

Zinc metal organic framework (MOF_Zn)-loaded goad nanoparticles (AuNPs) sol (Au@MOF_Zn), which was characterized by TEM, Mapping, FTIR, XRD, and molecular spectrum, was prepared conveniently by solvothermal method. The results indicated that Au@MOF_Zn had a very strong catalytic effect with the nanoreaction of AuNPs formation between sodium oxalate (SO) and HAuCl4. AuNPs in the new indicator reaction had a strong resonance Rayleigh scattering (RRS) signal at 370 nm. The indicator AuNPs generated by this reaction, which had the most intense surface enhanced Raman scattering (SERS) peak at 1621 cm -1. The new SERS/RRS indicator reaction in combination with specific aptamer (Apt) to fabricate a sensitive and selective Au@MOF_Zn catalytic amplification-aptamer SERS/RRS assay platform for carbendazim (CBZ), with SERS/RRS linear range of 0.025-0.5 ng/mL. The detection limit was 0.02 ng/mL. Similarly, this assay platform has been also utilized to detect oxytetracycline (OTC) and profenofos (PF).