• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2001년도 총회 및 춘계학술발표회
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• pp.206-209
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• 2001

This study presents the leaching characterization of heavy metals according to changes of pH by ANC test on slag produced in electric arc furnace, bottom ash produced in coal-fired plants and their recycling products. Availability test was performed to assess the fraction of the total concentration that under worst environmental conditions could become available for leaching. TCLP, KLT(Korea Leaching Test) and KLTS(Korea Leaching Test of Soil contamination) were carried out to compare the leaching capacity and to estimate the adequacy of regulatory leaching test. Results from regulatory leaching tests could be misleading because the variable ANC of wastes can lead to very different final leachate pHs. The final pH of the regulatory test is not the ambient pH in the disposal environment, the actual solubilities of contaminants in the field may be entirely different from those predicted by these regulatory tests. Leaching behaviour of by-products was changed by recycling processes, therefore acid neutralization capacity and availability of new products, not leaching concentration by one batch regulatory test, are necessary to determine the method of recycling.

• Macromolecular Research
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• 제16권8호
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• pp.734-740
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• 2008

A new crosslinked, poly(acrylic acid)-based, dehydrating agent was synthesized through solution polymerization. The Taguchi method, a robust experimental design, was adopted to optimize the synthetic conditions based on the moisture and water absorbing capacities of the dehydrating agent. The method applied for the experiment was a standard L27 ($3^8$) orthogonal array with eight parameters and three levels. By analyzing the variance of the test results, the most effective parameters to control the moisture absorbing capacity (MAC) and its rate were the kind of alkaline base (LiOH, NaOH, or KOH) used as a neutralizing agent of the acrylic acid monomer and the degree of neutralization: The maximum MAC of 40% was achieved at only 2 hat $32^{\circ}C$ and 50% RH when KOH was used as a base and the degree of neutralization was 90%, respectively. However, the water absorbing capacity (WAC) of the resulting dehydrating agent was very low at 158 g/g, indicating that WAC is unaffected by MAC and its rate in this system. The surface morphologies of the agents were examined using scanning electron microscopy (SEM).

• 한국광물학회지
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• 제32권4호
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• pp.249-258
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• 2019

산업화와 경제 발전에 따라 생산량, 사용량, 보관량, 운반량이 늘어난 산 물질들의 누출 사고가 빈발하고 있다. 지중 환경으로 유입된 누출 산은 지질매체와의 반응에 의해 궁극적으로 중화될 것으로 예상된다. 하지만 누출 산이 영향을 주는 공간적 및 시간적 범위는 산에 노출된 지질매체의 특성에 따라 달라질 것으로 예측된다. 본 연구에서는 국내에서 가장 사용량이 많은 황산을 한국의 지질을 대표할 수 있는 모델 지질매체들과 반응시켰다. 용액의 pH 변화를 지시자로 회분식 실험을 통해 모델 지질매체들의 산 완충능을 평가하였다. 그리고 산 중화에 기여하는 광물성분을 X-선회절분석을 통해 확인하였다. 실험 결과는 평가한 지질매체 중 사암이 가장 큰 중화능을 가졌으며, 캐올리나이트가 가장 낮은 중화능을 가졌음을 보여준다. 이 연구 결과는 지질매체에 대한 누출 산의 영향을 정량화하고 따라서 누출 산에 대한 지질매체들의 취약성을 예측하는데 기여할 것으로 기대된다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제19권3호
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• pp.142-152
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• 2014

In this study, generic characteristics of the acid mine drainage (AMD), removal efficiency of iron, aluminium and manganese by chemical treatment, electrolysis and hybrid process using electrolysis after neutralization were evaluated. The pH of AMD was inversely proportional to the rainfall. In dry-season, the average pH of AMD was ranged from 4.5 to 5.5, showing slight variation. However, the pH of AMD was gradually decreased along with rainfall and dropped to 3.02 in September showing the greatest rainfall. Removal efficiency of heavy metals by chemical treatments using three different neutralizing agents or by electrolysis was low. However, a hybrid process performed with electrolysis after addition of neutralization shows higher removal capacity for heavy metal ions than neutralization-alone and electrolysisalone process.

• Archives of Pharmacal Research
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• 제18권5호
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• pp.314-319
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• 1995

Antacid granules were prepared by agglomeration and powder method in high speed agitation type granulator. The copmositions of the test antacids were sodium bicarbonate nad magnesium carbonate nad a coating material was powder of polyvinylacetal diethyl-aminocacetate (AEA) and an additive material was talc powder. The dissolution characteristics of base from the antacid granules were investigated to evaluate neutralization capacity of hydrochloric profile of base and neutralization behavior, the following results were obtained : The prepared granules showed a pH-dependent dissolution pattern of a base. The dissolution profile of a base was varied with addition of talc powder as well as coating amount of AEA. The relationship between the ratio of dissolution retarded time for 20% and 10% AEA. The relationship between the ratio of dissolution retarded time for 20% AEA coated granules $\theta_{20}/\theta_{10}$ and the diameter reduction of the granules was explained by the rate process of neutralization of hydrochloric acid.

• Carbon letters
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• 제6권3호
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• pp.141-147
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• 2005

The carbon sample "O", phosphoric acid-activated carbon "OP", zinc chloride-activated carbon "OZ", and two steam activated carbons "OS" and "OS2" with different burn-off of 25% and 58% respectively, were prepared from olive stones. The textural properties were determined from the results of nitrogen adsorption at 77 K and by analyzing these results through the application of different adsorption models. The chemistry of the carbon surfaces was determined from the base neutralization capacities, acid neutralization capacity and surface pH. The sorption of $Pb^{2+}$ ions on to the carbons prepared was followed under dynamic and equilibrium conditions. The differences between the values of the textural parameters were attributed to the inapplicability of some adsorption models and to the heterogeneity of the microporous carbons. The sorption of $Pb^{2+}$ ions is favored on carbon and activated carbons. However, chemically activated carbons are more effective compared with steam-activated ones. The sorption of $Pb^{2+}$ ions were related to the chemistry of the surface rather than to the textural properties.

• 약학회지
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• 제33권2호
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• pp.111-117
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• 1989

The optimum reaction conditions for the acid consuming capacity of aluminum silicate synthesized from the reaction of sodium silicate solution and potassium aluminum sulfate solution were investigated by Box-Wilson experimental design, and the micromeritic properties were examined by the means of BET $N_2$ adsorption, Hg penetrometer and methylen blue adsorption. The chemical composition of the samples were analyzed by gravitic method. The results were found to be as follows: optimum reaction temperature $54.7^{\circ}C$, both concentrations of reactant soln 15.7%, reactants molar ratio (Al/Si) 0.5 and drying temperature $65.0^{\circ}C$. The acid consuming capacity of the sample prepared by above optimum conditions was 68 ml and the chemical composition was $Al_2O_3{\cdot}3.6SiO_2{\cdot}3H_2O$. The relationship between acid consuming capacity and micromeritic properties could not found in the range of experiments. Therefore, it is assumed that the acid consuming mechanism of aluminum silicate depends on the neutralization of $Al_2O_3$ and buffer action of $SiO_2$ in sample.

• Corrosion Science and Technology
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• 제8권3호
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• pp.110-115
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• 2009

At the onset of corrosion of steel in concrete, hydrogen ions usually evolve in the process of electrochemical reaction, thereby decreasing the pH of the pore solution, which can be buffered by cement hydration products, as being representatively illustrated by calcium hydroxide. Hence, a fall in the pH is dependent on properties of cement hydration (i.e. hydration products and degree of hydration). The present study tested acid neutralization capacity (ANC) of cementitious binders of OPC(Ordinary Portland Cement), 30% PFA(Pulverized Fuel Ash), 60% GGBS(Ground Granulated Blast Furnace Slag), 10% SF(Silica Fume) to quantify the resistance of cement matrix to a pH fall. Cement pastes were cast at 0.4 of a free W/C ratio with 1.5% chlorides by weight of binder in cast. Powder samples obtained crushed and ground specimen after 200 days of curing were diluted in still water combined with different levels of 1M nitric acid solution, ranging from 0.5 to 20 mol/kg. Then, the pH of diluted solution was monitored until any further change in the pH did not take place. It was seen that the pH of the diluted solution gradually decreased as the molar amount of nitric acid increased. At some particular values of the pH, however, a decrease in the pH was marginal, which can be expressed in the peak resistances to a pH fall in the ANC curve. The peaks occurred at the variations in the pH, depending on binder type, but commonly at about 12.5 in the pH, indicate a resistance of precipitated calcium hydroxide. The measurement of water soluble chloride at the end of test showed that the amount of free chloride was significantly increased at the pH corresponding to the peaks in the ANC curve, which may reflect the adsorption of hydration products to chlorides.

• 공업화학
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• 제7권4호
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• pp.698-706
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• 1996

메탄올로부터 HCHO를 생성하기 위하여 연속흐름 장치하에서 알칼리금속이 혼입된 여러가지 실리카-알루미나 촉매상에서 메탄올 탈수소반응을 수행하였다. HCHO의 생성은 촉매상의 Br${\ddot{o}}$nsted산보다는 Lewis산에 의존하였다. 이를 통해 메탄올의 탈수소촉매반응은 전자반응임을 알았고, 실리카-알루미나상의 Br${\ddot{o}}$nsted산은 알칼리금속의 혼입에 의해서 중화되었으며, Br${\ddot{o}}$nsted산의 중화효과는 혼입된 알칼리금속의 전자주게능력(electron-donating capacity)에 따라 다르게 나타났다. 그리고 메탄올 탈수소반응의 활성화에너지는 촉매의 Br${\ddot{o}}$nsted산점이 K에 의해 중화되었을 때 감소하는 경향을 보여주었다.

• Elastomers and Composites
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• 제54권3호
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• pp.232-240
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• 2019

A superabsorbent hydrogel (SAH) can absorb and retain water weighing more than a hundred times of their dry weight because of their three-dimensional hydrophilic structure. To fabricate an SAH, itaconic acid (IA) and vinyl sulfonic acid (VSA) were subjected to radical polymerization in an aqueous solution, wherein IA and VSA were neutralized, and then, a crosslinker and a thermal initiator were added in sequence. The structure of poly(IA-co-VSA) was characterized using attenuated total reflectance Fourier-transform infrared spectroscopy. We also studied the changes in the absorption properties of the SAH composites according to the polymerization temperature, degree of neutralization, type and content of the initiator used, and type and content of the crosslinker used. Thus, we could determine the effects of some synthetic factors on the absorption properties of the SAH.