In this study, several kinds of active carbons with high specific surface area and micro pore structure were prepared from the coconut shell charcoal using chemical activation method. The physical property of prepared active carbon was investigated by experimental variables such as activating chemical agents to char coal ratio, flow rate of inert gas and temperature. It was shown that chemical activation with KOH and NaOH was successfully able to make active carbons with high surface area of 1900~2500 m2/g and mean pore size of 1.85~2.32 nm. The coin cell using water-based binder in the electrolyte of LiPF6 dissolved in mixed organic solvents (EC:DMC:EMC=1:1:1 vol%) showed better capacity than that of oil-based binder. Also, it was found that the coin cell of water-based binder shows an improved cycling performance and coulombic efficiency.

PURPOSES: In this study, alkali-activated blast-furnace slag (AABFS) was investigated to determine its capacity to absorb carbon dioxide and to demonstrate the feasibility of its use as an alternative to ordinary Portland cement (OPC). In addition, this study was performed to evaluate the influence of the alkali-activator concentration on the absorption capacity and physicochemical characteristics. METHODS: To determine the characteristics of the AABFS as a function of the activator concentration, blast-furnace slag was activated by using calcium hydroxide at mass ratios ranging from 6 to 24%. The AABFS pastes were used to evaluate the carbon dioxide absorption capacity and rate, while the OPC paste was tested under the same conditions for comparison. The changes in the surface morphology and chemical composition before and after the carbon dioxide absorption were analyzed by using SEM and XRF. RESULTS: At an activator concentration of 24%, the AABFS absorbed approximately 42g of carbon dioxide per mass of paste. Meanwhile, the amount of carbon dioxide absorbed onto the OPC was minimal at the same activator concentration, indicating that the AABFS actively absorbed carbon dioxide as a result of the carbonation reaction on its surface. However, the carbon dioxide absorption capacity and rate decreased as the activator concentration increased, because a high concentration of the activator promoted a hydration reaction and formed a dense internal structure, which was confirmed by SEM analysis. The results of the XRF analyses showed that the CaO ratio increased after the carbon dioxide absorption. CONCLUSIONS : The experimental results confirmed that the AABFS was capable of absorbing large amounts of carbon dioxide, suggesting that it can be used as a dry absorbent for carbon capture and sequestration and as a feasible alternative to OPC. In the formation of AABFS, the activator concentration affected the hydration reaction and changed the surface and internal structure, resulting in changes to the carbon dioxide absorption capacity and rate. Accordingly, the activator ratio should be carefully selected to enhance not only the carbon capture capacity but also the physicochemical characteristics of the geopolymer.

Au 정광으로부터 Au Ag의 용출율을 향상시키기 위하여 기계적-화학적 활성화와 티오요소-티오시안산염 혼합용액을 적용하였다. 기계적-화학적 활성화를 이루기 위하여 정광 시료를 건식으로 그리고 습식으로 미분쇄하였다. 입도분포 분석과 XRD 분석 결과, 평균 입도 크기와 결정크기는 정광 시료보다 건식-시료에서 그리고 건식-시료보다 습식-시료에서 더 작게 나타났다. SEM과 XRD 분석 결과 기계적-화학적 활성화에 의해서 습식-시료에서 비정질화 현상이 관찰되었다. Au Ag에 대한 용출실험을 티오요소 용액, 티오시안산염 용액 그리고 티오요소-티오시안산염 혼합 용액으로 각각 수행하였다. Au Ag 용출율은 정광 시료보다 건식-시료에서 그리고 건식-시료보다 습식-시료에서 더 높게 나타났다. Au Ag는 티오요소 용액에서 보다 티오시안산염 용액에서 그리고 티오시안산염 용액에서보다 티오요소-티오시안산염 혼합 용액에서 더 높게 용출되었다. 습식-시료와 티오요소-티오시안산염 혼합 용액을 적용할 때 Au Ag가 99% 이상으로 용출되었다.

In this study, we examined the suitability of ten disinfection models for predicting the inactivation of Artemia sp. via single or combined physical and chemical treatments. The effect of Hydraulic Retention Time (HRT) on the inactivation of Artemia sp. was examined experimentally. Disinfection models were fitted to the experimental data by using the GInaFiT plug-in for Microsoft Excel. The inactivation model were evaluated on the basis of RMSE (Root Mean Square Error), SSE (mean Sum Square Error) and r2. An inactivation model with the lowest RMSE, SSE and r2 close to 1 was considered the best. The Weibull+Tail model was found to be the most appropriate for predicting the inactivation of Artemia sp. via electrolytic treatment and electrolytic-ultrasonic combined treatment. The Log-linear+Tail model was the most appropriate for modeling inactivation via homogenization and combined electrolytic-homogenization treatment. The double Weibull disinfection model was the most suitable for the predicting inactivation via ultrasonic treatment.

금-은 함유 황화광물 정광으로부터 Au와 Ag를 용출시키기 위하여 황화광물 정광을 건식과 습식으로 전처리하였다. 전처리한 황화광물에 대하여 광물학적 연구와 티오요소 용출실험을 수행하였다. 평균입도와 등전위는 정광시료에서 보다 건식 전-처리 시료에서 낮게 나타났고, 건식 전-처리 시료 보다 습식 전-처리 시료에서 더 낮게 나타났다. XRD 분석결과, 습식 전-처리 시료에서만 비정질의 특성이 나타났다. 정광시료에서, 최대의 Au, Ag 용출인자는 1.0 g의 티오요소, 1.0 M의 황산제2철, 2.0 M의 황산 농도에서 그리고 60℃의 용출온도에서였다. Au, Ag용출률은 건식 전-처리 시료에서 보다 습식 전-처리 시료에서 언제나 많이 그리고 빠르게 나타났다. 따라서, 향후 적당한 미분쇄 첨가제와 시간으로 전처리를 수행하고 비-시안 용매를 적용한다면 친환경적으로 Au, Ag를 용출시킬 수 있을 것으로 기대된다.

시멘트 대체 재료로서 플라이애쉬의 사용은 시멘트 생산비용을 절감시키는 효과를 창출하였다. 반면에 플라이애쉬 혼입콘크리트는 OPC에 비해 상대적으로 긴 양생시간과 초기강도의 발현 저하를 들 수 있어 이의 해결을 위해 물리적 방법, 온도 및 화학적 방법 등과 같은 다양한 활성화 기술의 적용을 통하여 플라이애쉬 혼입 콘크리트의 수화를 가속시킬 수 있고, 콘크리트의 부식 저항성을 향상시킬 수가 있다. 본 연구에서는 10～40%의 치환률을 가진 활성화된 플라이애쉬 시편을 통해 개방 회로형 전위측정(Open circuit potential measurement)을 수행하였고, 투수시험, 급속염화물침투시험 및 SEM(Scanning electron microscopy)촬영을 통해 OPC 콘크리트와 비교․분석 하였다. 또한, 치환률의 임계범위 20～30%의 경우에 있어서 활성화된 플라이애쉬를 사용한 콘크리트가 열화저항성에 있어서 개선효과가 나타나고 있음을 확인하였다. 또한 플라이애쉬를 화학적으로 활성화시킨 경우가 본 연구에서 수행된 다른 활성화 방법들에 비해 더욱 좋은 결과를 나타나고 있음도 확인하였다.