• 농업과학연구
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• 제23권2호
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• pp.250-260
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• 1996

Observed results of the adsorption between two competing anions for the shared sorption sites represent that the adsorption phenomena may depends on the characteristics of anion and available sorption sites in a given conditions. In binary systems, adsorption of one species can significantly influence the fate of the other anion, resulting in control of the extent of solute-adsorbate distributions throughout soil profile. And the proton-donation mechanisms by organic anions having a carboxyl as a functional group can also influence the adsorption of inorganic anions onto the hydroxylated sites of Fe and Al oxides. However, study of competitive adsorption of specifically adsorbed anions illustrates some of difficulties which arise in interpretation of reactions at oxide/aqueous solution interfaces. At least two factors prevented a simple analysis of reactions. First, at any pH value the maximum amount of adsorbate taken up at the surface depends on the identity of the anion. Second, it was necessary to postulate the sorption sites where the anion can be adsorbed. Hence, anions having non-specific adsorption characteristics are less capable for sorption sites, compared to those of specific adsorption characteristics, even though competition complies both ordinary and electrostatic interactions for sorption sites. Therefore, competition among chemical species in soil matrix can be of major significance in determining the effective mobility of any reactive anions with sorption sites.

• 한국세라믹학회지
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• 제33권8호
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• pp.849-854
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• 1996

boehmite which is the by-product in alcohol process contains anions such as $Cl^-,{NO_3}^-.or\; CH_3COO^-$ Influe-nce of these anions was studied on properties of $\alpha$-alumina powders prepared by treating the transformed ${\gamma}$-alumina with the alumina sol and $\alpha$-alumina seeds (d_{50}=0.36\mu\textrm{m}$) Disperal 20/1 and 10/1 containing $Cl^-$ produced spherical powder Disperal 20/2 with ${NO_3}^-$ produced equiaxed powder and Disperal 10/3 with $CH_3$ $COO^-$ irregular shaped and sized powder. All of these $\alpha$-alumina powders were submicron. Although the green density of the alumina powder derived from Disperal 10/1 by calcination at $1200^{\circ}C$/1h. was 53% it did not sinter even at $1550^{\circ}C$ for 2h. which implies that its d50 is greater than $3\mu\textrm{m}$. The others gave green densities in the range of 44~47% but they sintered as well as the AKP-30 at $1500^{\circ}C$/2 h or $1550^{\circ}C$/2 h.

• 한국토양비료학회지
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• 제19권2호
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• pp.139-145
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• 1986

담배식물이 흡수한 질산태질소가 조직중(組織中)에서 환원 되므로서 양(陽)이온과 음(陰)이온성분간(成分間)의 평형(平衡)에 미치는 영향을 구명하기 위하여 질소원(窒素源)을 달리한 배양액(培養液)으로 재배(栽培)하면서 무기(無機) 양음(陽陰)이온총량차이(總量差異)를 조사하고 질소환원(窒素還元) 및 유기산함량(有機酸含量)의 변화(變化)와 이온총량차이(總量差異)와의 관계(關係)를 검토(檢討)한 결과(結果) 1. $NO_3-N$ 배양액에서 자란 식물은 $NH_4-N$ 배양액의 것보다 양(陽)이온총량(總量)이 높았다. 무기음(無機陰)이온총량(總量)은 $NO_3+NH_4$혼합배양액(混合培養液)에서 가장 높게 나타났으나 $NO_3-N$ 배양액에서 가장 낮아서 무기 양음(陽陰)이온총량차이(總量差異)가 가장 컸고 $NH_4{^+}$가 함유된 배양액에서는 무기양음이온 총량차이가 비슷하여 무기이온으로서 거의 이온균형(均衡)이 유지(維持)되었다. 2. 식물체중(植物體中) 유기산(有機酸)은 malic acid의 분포가 가장 컸으며 $NO_3-N$ 배양액식물은 유기산(有機酸)이 다량함유(多量含有)되어 있으나 $NH_4-N$ 또는 혼합배양액(混合培養液)의 것은 거의 검출(檢出)되지 않았다. $NO_3-N$ 배양액식물(培養液植物)은 유기산총량(有機酸總量)이 무기음(無機陰)이온 총량(總量)보다 초과(超過)되어 유기산(有機酸)에 의한 이온균형(均衡)비율이 크나 $NH_4-N$ 배양액식물은 이온균형(均衡)에 차지하는 유기산(有機酸)비율이 극히 소량이었다. 3. $NO_3-N$식물(植物)은 질산환원(窒酸還元)이 왕성하게 진행되므로서 유리(遊離)된 양(陽)이온과의 이온균형(均衡)을 위하여 유기산(有機酸)이 다량(多量) 함유(含有)되었다.

• 한국토양비료학회지
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• 제49권5호
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• pp.541-547
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• 2016

In this experiment we investigated the influence of various anions including oxalic acid encountered as solution phase in soil on the adsorption and desorption of sulfate in Chungwon Bt soil. The effect of chloride and nitrate on the adsorption of sulfate was not significant, suggesting that sulfate was better able to compete for adsorption sites at concentrations studied, in contrast to the large reduction in the amount of chloride adsorbed in the presence of sulfate. The results of competition for sorption sites between sulfate and anion showed that the simultaneous presence of two anions in solution was effective in reduction of competing anion at a maximum value of adsorption, due to the similar adsorption mechanism for anion competition. Therefore, the variation in the buffer power of the acids will produce a change in the strength and amount of adsorption and the competitive ability.

• Corrosion Science and Technology
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• 제14권6호
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• pp.253-260
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• 2015

The pitting behaviours of 304L and 316L stainless steels were investigated at $3^{\circ}C$ to $90^{\circ}C$ in 1 M solutions of NaCl, NaBr and NaI by potentiodynamic polarization. The temperature dependences of the pitting potential varied according to the anion, being near linear in bromide but exponential in chloride. As a result, at low temperatures grades 304L and 316L steel are most susceptible to pitting by bromide ions, while at high temperatures both stainless steels were more susceptible to pitting by small chloride anions than the larger bromide and iodide. Thus, increasing temperature appears to favour attack by smaller anions. This paper will attempt to rationalise both of the above findings in terms of the point defect model. Initial findings are that qualitatively this approach can be reasonably successful, but not at the quantitative level, possibly due to insufficient data on the mechanical properties of thin passive films.

• 한국지반환경공학회 논문집
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• 제12권10호
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• pp.57-62
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• 2011

이 연구는 Methyl tert Btyl Ether(MTBE)의 광촉매반응을 통한 제거시에 다양한 음이온($Cl^-$, $NO_3{^-}$, $HCO_3{^-}$)들의 영향을 통계적 방법을 사용하여 조사하였다. 이 공정은 일반적으로 UV의 존재 하에 수용액상에 생성되는 Hydroxyl radicals(OH라디칼)의 생성에 기초하며, 이러한 라디칼들의 생성은 수용액 상의 무기 음이온들이 OH라디칼과의 반응에 의해 광분해를 방해한다. 이런 무기음이온들의 영향은 반응표면법(RSM)의 한 종류인 혼합물분석(Mixture analysis)를 통해 $Cl^-$, $NO_3{^-}$와 $HCO_3{^-}$의 독립변수들을 수학적으로 표현하였다. 분산분석(Analysis of variance; ANOVA)의 회귀분석항은 유의한 p값(p<0.0001)과 높은 결정계수($R^2$=99.28%, ${R^2}_{adj}$=98.91%)를 나타냈다. 그리고 등고선도(Contour plot)와 반응표면도(Response surface plot)는 $UV/H_2O_2$ 공정에 기초한 MTBE 광분해에 대한 무기 이온들의 영향을 나타내었다. 이 연구의 결과는 MTBE의 광분해에 대해 $Cl^-$와 $HCO_3{^-}$ 이온이 OH라디칼의 생성을 방해하는 것으로 나타났고 이 두 인자에 의한 상호작용이 관찰되었다.

• Archives of Pharmacal Research
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• 제5권2호
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• pp.97-101
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• 1982

Depending upon the results obtained by the bromolactonization of olefinic acids (9-11) by means of N-bromosaccharin (4), the influence of the stabilities of the imidic anions resulted from heterolytic cleavage of N-haloimides, such as N-bromosuccinimide (1), N-bromophthalimde (2), and N-bromosaccharin (3) in dry N, N-dimethylformamide on the reactivity is elucidated.

• Bulletin of the Korean Chemical Society
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• 제33권11호
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• pp.3601-3606
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• 2012

Structural properties of a small hexapeptide molecule modeled after metal-binding siderochrome immersed in a room-temperature ionic liquid (RTIL) are studied via molecular dynamics simulations. We consider two different RTILs, each of which is made up of the same cationic species, 1-butyl-3-methylimidazolium ($BMI^+$), but different anions, hexafluorophosphate ($PF_6{^-}$) and chloride ($Cl^-$). We investigate how anionic properties such as hydrophobicity/hydrophilicity or hydrogen bonding capability affect the stabilization of the peptide in RTILs. To examine the effect of peptide-RTIL electrostatic interactions on solvation, we also consider a hypothetical solvent $BMI^0Cl^0$, a non-ionic counter-part of $BMI^+Cl^-$. For reference, we investigate solvation structures in common polar solvents, water and dimethylsulfoxide (DMSO). Comparison of $BMI^+Cl^-$ and $BMI^0Cl^0$ shows that electrostatic interactions of the peptide and RTIL play a significant role in the conformational fluctuation of the peptide. For example, strong electrostatic interactions between the two favor an extended conformation of the peptide by reducing its structural fluctuations. The hydrophobicity/hydrophilicity of RTIL anions also exerts a notable influence; specifically, structural fluctuations of the peptide become reduced in more hydrophilic $BMI^+Cl^-$, compared with those in more hydrophobic $BMI^+PF_6{^-}$. This is ascribed to the good hydrogen-bond accepting power of chloride anions, which enables them to bind strongly to hydroxyl groups of the peptide and to stabilize its structure. Transport properties of the peptide are examined briefly. Translations of the peptide significantly slow down in highly viscous RTILs.

• Membrane and Water Treatment
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• 제11권3호
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• pp.201-206
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• 2020

Electrodialysis (ED) is used in wastewater treatment, during the processing and recovery of beneficial materials, to produce usable water. In this study, sulfate and chlorine ions, which are the anions majorly used for electroplating, were studied as factors affecting the recovery of copper, nickel and water from wastewater by electrodialysis. Although the removal rates of copper and nickel ions were slightly higher with the use of chlorine ions than of sulfate ions, the removal efficiencies were above 99.9% under all experimental conditions. The metal ions of the plating wastewater flowed through the ion exchange membrane of the diluate tank and the concentrate tank while all the water moved together due to electro-osmosis. The migration of water from the diluate tank to the concentrate tank was higher in the presence of a monovalent chloride ion compared to that of a divalent sulfate ion. When sulfate was the anion used, the recoveries of copper and nickel increased by about 25% and 30%, respectively, as compared to the chloride ion. Therefore, when divalent ions such as sulfate are present in the electrodialysis, it is possible to reduce the movement amount of water and highly concentrate the copper and nickel in the plating wastewater.

• Environmental Engineering Research
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• 제15권2호
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• pp.93-98
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• 2010

This study aims to determine the chemical composition and seasonal variation of atmospheric acid deposition in order to identify possible sources contributing to precipitation. Sampling and analysis of 132 wet deposition samples were carried out from January to December 2008 at Mae Hia Research Center, Chiang Mai University, Chiang Mai Province. Total precipitation was 1,286.7 mm. Mean electro-conductivity and pH values were 0.94 mS/m and 6.27, respectively. Major cations ($Na^+$, ${NH_4}^+$, $K^+$, $Ca^{2+}$, and $Mg^{2+}$) and major anions ($HCOO^-$, $CH_3COO^-$, $Cl^-$, ${NO_3}^-$, and ${SO_4}^{2-}$) were determined by Ion Chromatography. The relative volume weight mean concentrations of anions, in descending order, were ${SO_4}^{2-}$ > ${NO_3}^-$ > $Cl^-$ > $CH_3COO^-$ > $HCOO^-$ and those of cations were $NH_4^+$ > $Ca^{2+}$ > $Mg^{2+}$ > $K^{+}$ > $Na^+$. Results of a principle component analysis highlighted the influence of various possible sources of ions such as agricultural activity, fuel combustion, marine sources, soil resuspension, and biomass burning.