As the number of aging nuclear power plants increases, the market for dismantling nuclear power plants is growing rapidly. About 40% of the cost of dismantling nuclear power plants is the waste treatment cost incurred during the dismantling process, of which concrete waste accounts for a significant portion of the total waste. Securing technology for reducing and recycling concrete waste is very important not only in terms of economy but also in terms of environment. The objective is to synthesize geopolymer using inorganic materials from cement fine powder in concrete waste. Cement fine powder in concrete waste has a large amount of inorganic elements necessary for filing materials for radioactive waste treatment such as CaO and SiO2. In particular, Ca(OH)2 is synthesized by extracting Ca2+ from concrete waste. It can be used as an alkali activator to synthesize geopolymer. The mortar from crushed concrete was used as a source of calcium. The first step is to react with concrete waste and hydrochloric acid to extract ions. The second step is to react with NaOH and synthesize Ca(OH)2. The product was divided into two stages according to the reaction method and order. The first and second products were washed and dried, and then XRD and XRF were performed. The second product was matched only Ca(OH)2 and CaCO3 at the XRD peak. In the case of XRF, it was analyzed to have a purity of 67.80–78.73%. Synthesis of geopolymer by recycling materials extracted from concrete waste can reduce disposal costs and improve the utilization rate of disposal sites.

In this study, an aerosol process was introduced to produce CaCO3. The possibility of producing CaCO3 by the aerosol process was evaluated. The characteristics of CaCO3 prepared by the aerosol process were also evaluated. In the CaCO3 prepared in this study, as the heat treatment proceeded, the calcite phase disappeared. The portlandite phase and the lime phase were formed by the heat treatment. Even if the CO2 component is removed from the calcite phase, there is a possibility that the converted CO2 component could be adsorbed into the Ca component to form a calcite phase again. Therefore, in order to remove the calcite phase, carbon components should be removed first. The lime phase was formed when CO2 was removed from the calcite phase, while the portlandite phase was formed by the introducing of H2O to the lime phase. Therefore, the order in which each phase formed could be in the order of calcite, lime, and portlandite. The reason for the simultaneous presence of the portlandite phase and the lime phase is that the hydroxyl group (OH−) introduced by H2O was not removed completely due to low temperature and/or insufficient heating time. When the sufficient temperature (900°C) and heating time (60 min) were applied, the hydroxyl group (OH−) was removed to transform into lime phase. Since the precursor contained the hydrogen component, it could be possible that the moisture (H2O) and/or the hydroxyl group (OH−) were introduced during the heat treatment process.

원자력발전소 해체 시 발생하는 금속폐기물은 폐기물 중에서 많은 비중을 차지하고 있다. 본 연구에서는 국내 자체처분 규제 요건 및 국내 기관별 자체처분현황을 조사하였다. 실제 원자력발전소 해체 시 발생되는 금속폐기물의 자체처분을 위하여 RESRAD-RECYCLE 코드를 이용하였으며 26가지 시나리오에 대한 선량평가를 수행하였다. 평가결과는 원자력발전소 해 체 시 자체처분 및 재활용에 관한 사전자료로서 활용가치가 있을 것으로 사료된다. 추후 자체처분을 통한 처분비용 저감효 과 연구가 추가로 가능할 것으로 판단된다.

고농도 유기질 폐수처리를 위해 전기화학적 방법의 사용에 있어 관심이 고조되고 있다. 전기화학적 방법의 기술은 음식물폐수 및 공업적 폐수 문제를 해결하는데 이상적 처리 방법이다. 다른 화학적 처리 방법과는 다르게 전기화학적 처리장치는 2차 폐수의 부피를 증가시키지 않고 용수와 유기질 비료로 재활용한다. 전기화학적 방법은 전해부상장치를 무기화학적 약품과 병행하여 더욱 효과적으로 음식물 폐수를 처리한다. 이 연구는 2차 처리로 초음파와 오존처리로 탈색, COD와 BOD가 격감함으로 용수 및 유기질 비료로 활용하도록 실험하였다.

The waste substrate from sawdust based cultivation of Heicium erinaceum was reused. This process was conducted three times. Even when the waste substrate was reused at three times, the yield of fruiting bodies was equal to that of fresh medium. However, the yield of the 1st-waste substrate was the best of all waste substrate media and the yields of waste substrate media deceased with recycling times. The yield of the 1st or the 2nd waste substrate medium increased by 1.3-1.4 times compared with that of the fresh medium. The content of low molecular α-glucan and β-glucan of the 1st or the 2nd waste substrate medium increased and C-N ratio of the 1st or the 2nd waste substrate medium decreased. These results suggest that low molecular glucan and N sources contribute to increasing fruiting bodies. It was clear that the 1st and the 2nd waste substrate were useful for the cultivation material of Heicium erinaceum.

The effect of the metal oxide catalyst in the dimerization of waste vegetable oil was investigated. The high efficiency and recyclability has allowed different metal oxides to be used as catalysts in numerous synthetic reactions. Herein, clay, aluminum, titanium, calcium, magnesium and silicon oxide micro/nanoparticles are used in a Diels-Alder reaction to catalyze the production of the dimer acids. The metal oxides assist the electron transfers during cyclization to produce the desired product. Liquid chromatography mass spectroscopy (LC-MS) and gel permeation chromatography (GPC) were used to verify the production of dimer acids. For the confirmation of cyclization, compounds were analyzed using the nuclear magnetic resonance (NMR) spectroscopy. From the analysis, silylated or pristine clay showed its effectiveness as a catalyst in dimerization. Furthermore, alumina and alumina/silica composite showed successful performance in the reaction to yield cyclic dimer acids. These result suggested that metal oxides and montmorillonite might be used in synthesis of dimer acids for the recycle of waste vegetable oils.

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 specific 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 alkali 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(l/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 actviated carbon, they could look forward to an expected economical effect.