• 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.

• 한국환경과학회지
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• 제6권5호
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• pp.497-503
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• 1997

This study was performed to Investigate the utilization of waste concretes for neutralization and removal of heavy metals In plating wastewater, because waste concretes have been known to be very porous, to have high species surface area and to have alkaline minerals such as calcium. The results obtained from this research showed that waste concretes had a buffer capacity to neutralize an acidic alali system in plating wastewater. Generally, neutralization and removal rate of heavy metals were excellent in the increase of waste concrete amounts and a small size. Because a coefficient of correlation was high, it seemed that removal of heavy metals could be explained by Freundlich and Langmuir isotherms. If we reflected the adsorption capacity(k) and adsorption intensity(1/n) of Freundlich isotherm, we couldn't consider waste concretes as a good adsorbent. But, we could know that waste concretes were capable of removing a part of heavy metals. In point of building waste debris, if waste concretes substituted for a valuable adsorbent such as actuated carbon, they could look forward to an expected economical effect.

• 환경위생공학
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• 제15권3호
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• pp.62-69
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• 2000

In point of recycling wastes, batch test was conducted to examine the neutralization and Fe removal from laboratory wastewater using wastes. Oyster shell and slag had a buffer capacity to neutralize an acidic wastewater but tire rubber didn't. With increasing reaction time, dosage and agitation speed, Fe was well removed by wastes. As a result on the experiments of Freundlich isotherm, the adsorption intensities(1/n) were 0.32∼0.46 and the adsorption capacities(k) were 4.3∼4.6 for removing Fe from laboratory wastewater by wastes. In view of these results, it was estimated that wastes containing the similar compositions as these could utilize the neutralization and adsorption of heavy metals in laboratory wastewater.

• 한국환경보건학회지
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• 제22권3호
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• pp.81-87
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• 1996

The purpose of this research is to examine the utilization of oyster shells for neutralization and removal of heavy metal ions in plating wastewater, because oyster shells have been known to be very porous, to have high specific surface area and to have alkaline minerals such as calcium and magnesium. The results obtianed from this research showed that oyster shells had a buffer capacity to neutralize an acidic.alkali system in plating wastewater. Generally, it could be showed that the removal efficiencies of heavy metal ions were very influenced by reaction times and oyster shell dosages. In point of ocean waste, if oyster shells substituted for a valuable adsorbent such as actviated carbon, they could look forward to an expected economical effect.

• 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.

• 한국통신학회논문지
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• 제38A권12호
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• pp.1117-1124
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• 2013

최근 무선트래픽 수요가 폭발적으로 증가하면서 셀룰라 무선망에서 이를 효율적으로 지원하기 위한 스몰셀 연구가 활발히 수행중이다. 본 논문은 스몰셀 구현의 가장 큰 걸림돌인 다중셀 간섭을 효율적으로 해결하기 위한 간섭상쇄 기법에 대해 연구하였다. 각 사용자의 메시지가 기지국 혹은 릴레이를 통하여 전달되는 경우, 무선채널의 시변특성을 이용한 간섭상쇄 기법을 제안하였다. Amplify-and-forward (AF) 에 기반한 기존 접근방식은 잡음증폭 특성으로 인하여 신호대잡음비가 낮은 영역에서는 심한 성능열화를 보였다. 본 논문은 최근 개발된 compute-and-forward (CF) 에 기반한 간섭상쇄를 제안하여 이러한 문제를 해결하고 신호대잡음비가 작은 영역에서 전송율을 크게 개선하였다.

• 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).

• 한국지하수토양환경학회지:지하수토양환경
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• 제26권6호
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• pp.65-73
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• 2021

Since the amount of red mud, generated from aluminum smelting process as a by-product, has increased worldwide, the recycle and metal resource recovery from the red mud is becoming more important. In this study, in order to recycle the red mud as a soil stabilizer to remediate arsenic contaminated soils, neutralization of red mud was investigated. Red mud was neutralized by washing with distilled water and NaCl, CaCl₂, FeCl₃, and HCl solutions and heating at 200-800℃, and arsenic stabilization characteristics in soils were evaluated with the neutralized red mud. Although washing with distilled water was not effective in neutralizing red mud, the application of the washed red mud to soils lowered the soil pH compared to the application of untreated red mud. Among NaCl, CaCl₂, FeCl₃, and HCl solutions, washing with FeCl₃ showed the most effective in lowering pH of the red mud from pH 10.73 to pH 4.26. Application of the neutralized red mud in soils resulted in quite different arsenic stabilization efficiency depending on soil samples. In M1 soil, which showed relatively high arsenic stabilization efficiency by untreated red mud, the neutralization of red mud resulted in little effect on arsenic stabilization in soil. On the other hand, in M2 soil, which showed low arsenic stabilization efficiency by untreated red mud, the neutralization of red mud increased arsenic stabilization significantly. Soil characteristics such as clay minerals and pH buffering capacity seemed to affect reactions between red mud and soils, which resulted in different effects of the red mud application on soil pH and arsenic stabilization efficiencies.

• 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.