The advanced oxidation treatment using persulfate and zero-valent iron (ZVI) has been evaluated as a very effective technology for remediation of soil and groundwater contamination. However, the high rate of the initial reaction of persulfate with ZVI causes over-consumption of an injected persulfate, and the excessively generated active species show a low transfer rate to the target pollutant. In this study, ZVI was modified using selenium with very low reactivity in the water environment with the aim of controlling the persulfate activation rate by controlling the reactivity of ZVI. Selenium-modified ZVI (Se/ZVI) was confirmed to have a selenium coating on the surface through SEM/EDS analysis, and low reductive reactivity to trichlroethylene (TCE) was observed. As a result of inducing the persulfate activation using the synthesized Se/ZVI, the persulfated consumption rate was greatly reduced, and the decomposition rate of the model contaminant, anisole, was also reduced in proportion. However, the final decomposition efficiency was rather increased, which seems to be the result of preventing persulfate over-consumption. This is because the transfer efficiency of the active species (SO4-∙) of persulfate to the target contaminant has been improved. Selenium on the surface of Se/ZVI was not significantly dissolved even under oxidation conditions by persulfate, and most of it was present in the form of Se/ZVI. It was confirmed that the persulfate activation rate could be controlled by controlling the reactivity of ZVI, which could greatly contribute to the improvement of the persulfate oxidation efficiency.

Forests are valuable natural resources for people living around the mountains. In particular, the comfortable feeling or healing is one of the most important benefits obtained from forests. This healing can be possible by many aspects of forests, including the landscape, natural sounds, anions, and pleasant aromas. We focused on the volatile organics from forest causing pleasant aromas, phytoncides. Twenty phytoncides were monitored from February to September in a national tree garden (BaekDoDaeGan SooMokWon). Five sites were monitored two times per month and 20 phytoncides were detected. Borneol showed the highest annual average concentration and the order of concentration was borneol > mycene > sabinene > limonene > α-pinene. The average phytoncide concentration was relatively high in spring and summer season when the trees were physiologically active. Daily monitoring showed that the afternoon hours had higher concentrations of phytoncides than the morning hours, which may be due to the stabilized atmospheric conditions at the sites. Among the five sites, coniferous forests gave higher phytoncide emissions than broadleaf tree forests. The current study showed that forests produce several phytoncides that cause a healing effect and a forest bath may be beneficial to the health of visitors to forests.

본 연구에서는 꼬막(cockle), 전복(abalone), 가리비(scallop) 패각을 이용하여 중금속 제거효율 평가를 수행하였다. 꼬막, 전복, 가리비의 주 구성광물은 각각 아라고나이트, 아라고나이트와 방해석, 방해석으로 구 성되어 있다. 각 패각들의 비표면적은 2.7241 m2/g에서 4.5481 m2/g까지 다양하며 가리비 > 전복 > 꼬막이다. 반응 후 중금속 분석 결과 As는 패각에 의한 흡착이나 pH 상승에 의한 침전 제거 효과가 나타나지 않았다. 납은 반응 초기에 모든 패각 시료에서 모두 제거되었다. 카드뮴과 아연은 매질에 따라 약간의 차이가 있지만 제거 효율은 가리비 > 전복 > 꼬막 순으로 나타났다. 중금속 제거 효율은 가열 시료가 원시료 비해 약간 높 으며, 비표면적이 클수록 높은 경향이 있다.

몽골(6종), 미국(1종), 한국(9종)지역에서 채취한 총 16종의 천연 제올라이트를 X-선 회절 분석, X-선 형광 분석, 열 시차, 열 중량 분석 및 양이온 교환능 분석을 통해 특성분석을 수행하였다. 16종의 시료 모두 두 종류 이상의 광물상이 공존하는 혼합광 형태이며, 주로 클라이놉틸로라이트, 휼란다이트, 모데나이트 및 차 바자이트와 같은 광물의 조합으로 이루어져 있으며, 일부 시료에서는 운모 점토광물인 일라이트와 석영과 같은 광물이 불순물로 함유되어 있었다. X-선 형광 분석 결과 16종의 천연 제올라이트는 SiO2, Al2O3, K2O, CaO, Na2O, MgO 및 Fe2O3 산화물이 함유되어 있었다. 미국 천연 제올라이트인 U-1 시료가 223.3 meq/100 g으로 양이온 교환능이 가장 높게 나타났으며 몽골 천연 제올라이트에서는 M-6 시료가, 한국 천연 제올라이트에서는 K-1 시료가 각각 166.6 meq/100 g으로 가장 높게 나타났다. 열시차 및 열중량 분석 결과 16종의 시료 모두 600℃까지 열적으로 안정성이 우수한 것을 확인 하였다.

Heavy metal contaminations were investigated in fishes inhabiting the basins of Andong, Imha and Yeongju dam basins along the upper stream of the Nakdong river. The characteristics of heavy metals contamination in fish were investigated based on sampling sites located in the Andong dam basin. The muscle tissue was analyzed for 267 objects of 26 species from the Andong dam, 50 objects of 17 species from Imha dam, 38 objects of 9 species fromYoungju dam basin.The type and amount of heavy metals concentrated in the body of the fishes was found to be species-dependent. The heavy metal species which contamination increase through the Seokpo smelter are chromium, zinc, cadmium, and lead, and these are very likely the influence of the smelter. The concentration of eight heavy metals in fish from the Andong dam basin was higher than that in fish from the Imha and Youngju dam basins; the values for zinc, arsenic, and cadmium were significantly higher. However, mercury and lead exhibited high values in the Imha and Yeongju dam basins, respectively.

Environmental contamination by organic compounds are not only restricted to water, but extends to soil and groundwater as well. However, highly oxidized compounds, such as halogenated organics and nitro-compounds, can be detoxified employing reducing methods. Permeable reactive barrier is one of the representative technologies where zero-valent metals (ZVMs) are employed for groundwater remediation. However, organics contaminates often contaminate the unsaturated zone above the groundwater. Despite the availability of technologies like soil vapor extraction and bioremediation, removing organic compounds from this zone represents several challenges. In this study, the reduction of nitrobenzene to aniline was achieved using zero-valent iron (ZVI) under unsaturated conditions. Results indicated that the water content was an important variable in this reaction. Under dry conditions (water content = 0.2%), the reduction reaction was inhibited; however, when the water content was between 10% and 25% (saturated condition), ZVI can reduce nitrobenzene. Palladized iron (Pd/Fe) can be used to reduce nitrobenzene when the water content is between 2.5% and 10%. The reaction was evaluated over a wide range of temperatures (10 – 40 °C), and the results indicated that increasing the temperature resulted in increased reaction rates under unsaturated conditions.

Organic contaminants can be released into water environments due to chemical accidents and exist as dissolved and non-aqueous phase liquids (NAPL). Fenton oxidation was tested for bisphenol A and nitrobenzene as model organic contaminants in dissolved and NAPL states. Fenton oxidation was successfully applied for both of the dissolved and NAPL states of the two pollutants and the results indicated that a quick treatment was needed to reduce the risk from a chemical accidents instead of carrying out oxidation after the contaminants dissolve in water. A set of Fenton reactions were tested under seawater conditions because chemical accidents often occurs in the ocean. Chloride ions act as radical scavengers and inhibit Fenton oxidation. The reaction rate is inversely proportional to salt contents and the reduced reaction rate can be compensated by increasing the quantity of the oxidizing agents. The current study showes that Fenton oxidation could be applied as a quick treatments for organic contaminant in dissolved and NAPL state organic contaminants released as a result of leaks or chemical accidents.

In this study, the applicability of reduction-oxidation-linked treatment was evaluated for nitrobenzene and a by-product by analyzing the reaction kinetics. Nitrobenzene showed very low reactivity to persulfate that was activated using various methods. Nitrobenzene effectively reacted through the reduction process using Zero-Valent Iron (ZVI). However, aniline, a toxic substance, was produced as a by-product. Reduction-oxidation-linked treatment is a method that can allow the oxidative degradation of aniline after reducing nitrobenzene to aniline. The experimental results show improved reactivity and complete decomposition of the by-product. Improved reactivity and decomposition of the by-product were observed even under conditions in which the reduction-oxidation reaction was induced simultaneously. No activator was injected for persulfate activation in the process of reducing oxidant linkage, and the activation reaction was induced by ferrous iron eluted from the ZVI. This indicates that this method can be implemented relatively simply.

본 연구에서는 안동댐 퇴적물의 일반항목과 중금속의 용출 특성에 대해 조사하였다. 용출 실험은 카드뮴, 구리, 납, 크롬, 아연, 수은, 비소, 철, 망간 등 중금속 9개 및 pH, 총인, 총질소 등 일반 3개 항목에 대해 혐기성과 호기성 조건에서 60일간 실험을 수행하였다. 총질소와 총인은 호기성 조건에 비해 혐기성 조건의 용출이 높게 나타났으며, 일부 시료에서 높은 농도가 검출되었다. 대부분의 중금속의 용출율은 아주 낮았으며, 퇴적물에서 함유량이 높은 비소와 카드뮴도 최대 용출량이 각각 0.028 mg/L, 0.003 mg/L로 낮은 값을 나타낸다. 5단계 연속추출연구에서는 쉽게 용출될 수 있는 이온교환형태나 흡착한 형태의 분율이 전체 함유량의 10% 미만으로 낮게 나타났다. 대부분의 중금속은 왕수에 용해되는 잔류(residual)형태로 존재하고 있으며, 특히 독성이 높고 오염도가 높은 비소와 카드뮴의 경우 잔류형태로 존재하는 비율이 각각 80%와 95%로 오염도에 비해 짧은 시간에 용출되어 유해성을 일으킬 가능성은 낮은 것으로 판단된다.

본 연구에서는 낙동강수계의 안동댐 퇴적물에 대한 오염도 조사 및 평가를 수행하였다. 안동댐 상류 40 km까지 약 5 km 간격으로 호수의 중간, 좌, 우지점에서 성층기와 전도기로 구분하여 퇴적물 시료를 채취하였다. 일반 항목인 강열 감량, 총질소, 총인의 경우 오염도가 낮지만, 중금속의 경우 비소와 카드뮴의 오염도는 매우 높다. 지천 및 대조군에 비해 댐 내 퇴적물의 오염도가 높으며, 시료채취 시기별로는 성층기에 크 롬, 구리, 납의 농도가 높고, 순환기에 아연의 농도가 높은 경향을 보인다. 상하류의 위치에 따른 농도 차이 를 나타내는 중금속은 비소, 카드뮴, 망간, 아연이며 차이를 보이지 않는 항목은 크롬, 구리, 수은, 철, 납 등 이다.

나노물질에 대한 연구와 산업화가 급격히 진행되면서 수환경으로 유출되는 나노물질의 양도 점차 많아지고 있다. 특히 은나노물질의 경우 은의 항균성으로 인하여 다양한 분야에서 사용되고 있으며 환경으로 유출되어 입자상태와 용해된 상태로 존재할 수 있다. 은나노물질과 은이온은 생태환경에 악영향을 줄 수 있으며 미국에서는 2차 먹는물 규제 항목(secondary drinking water standards)으로 정하고 있으며 규제농도는 0.1 mg/L로 정하여 관리하고 있다. 본 연구에서는 경북지역의 지하수와 소규모 먹는 물 공급시설을 대상으로 은의 농도를 측정하였으며 오염 정도를 미국 EPA 기준과 비교하고 시료를 채취한 지역의 특성, 물의 사용 목적 등을 고려하여 분석하였다. 총 293개의 시료 중 EPA의 secondary drinking water standards를 초과한 시료는 2개이며 비율로 0 .6 7%이다. 검출률은 마을 상수도와 소규모 급수시설에서 상대적으로 높으며 농도 기준으로는 지하수에서 상대적으로 높은 농도를 보여 인위적 오염원과 지질적 기원이 동시에 작용한 것으로 판단되었다.

Oxidative degradation of phenol, three monochlorophenols (2-chlorophenol, 2-CP; 3-chlorophenol, 3-CP; 4-chlorophenol, 4-CP), four dichlorophenols (2,3-dichlorophenol, 2,3-DCP; 2,4-dichlorophenol, 2,4-DCP; 2,5-dichlorophenol, 2,5-DCP; 2,6-dichlorophenol, 2,6-DCP), and two trichlorophenols (2,4,5-trichlorophenol, 2,4,5-TCP; 2,4,6-trichlorophenol, 2,4,6-TCP) was conducted with heat activated persulfate. As the number of chlorinations increased, the reaction rate also increased. The reaction rate was relatively well fitted to the zero-order kinetic model, rather than the pseudo-first order kinetic model for the reactions at 60℃, which can be explained by insufficient activation of the persulfate at 60℃, and the oxidation reaction of 2,4,6-TCP at 70℃ was relatively well fitted to the pseudo-first order kinetic model. The oxidation reaction rate generally increased with increase of persulfate concentration in the solution. 2,6-dichloro-2,5-cyclohexadiene-1,4-dione was found as a degradation product in a GC/MS analysis. This compound is a non-aromatic compound, and one chlorine was removed. This result is similar to the result of previous studies. The current study proved that heat activated persulfate activation could be an alternative remediation technology for phenol and chlorophenols in soil and groundwater.

본 연구에서는 안동댐 퇴적물의 중금속 및 용출 특성을 분석하기 위하여 X-선 회절 분석, ICP 분석, 용출 실험을 수행하였다. X-선 회절 분석 결과 안동댐 퇴적물의 주구성 광물은 석영, 사장석, 녹니석, 일라이트이다. 퇴적물에 대한 ICP 분석 결과 비소와 카드뮴의 농도가 매우 높게 나타났다. 용출 실험은 교란 상태에서 호기성 및 혐기성 환경에서 수행하였다. 용출 실험 결과 혐기성보다 호기성 상태에서 더 많은 중금속이 용출되는 경향을 나타내었다. 호기성 상태에서 시간이 지남에 따라 농도가 증가하는 항목은 망간, 아연, 카드뮴이며 혐기성 상태에서는 망간, 철, 비소이다. 퇴적물 중금속 농도 대비 용출비는 호기성 및 혐기성 환경에서 각각 Mn > Cd > Zn > Ni > Cu > As > Pb ≒ Fe ≒ Cr이 며 Mn > As > Cu > Ni > Zn > Pb ≒ Cd ≒ Fe ≒ Cr이다.

최근 국내에서 발생한 지진으로 인한 교량, 지하철, 건물 등의 손상위험 증가로 철근콘크리트 기둥의 내진보강 공사 수요가 증가하고 있다. 경량부재인 강봉 간편체결을 통한 철근콘크리트 기둥 내진보강공법은 지진에 따른 노후화 구조물의 갑작스러운 붕괴를 선제적으로 방지하고 인적, 물적 피해를 최소화하여 복구비용과 기간을 줄일 수 있다. 또한 전선, 통신, 관로 등 지장물 대응성이 우수하고 협소한 장소에서도 급속시공이 가능하여 경제적이고 공기단축이 가능한 공법이라 할 수 있다.

본 연구에서는 안동댐과 임하댐의 퇴적물과 유입되는 부유물의 특성을 색도분석, X-선회절분석 및 유도플라즈마/질량분석법을 이용하여 분석하였다. 안동댐과 임하댐으로 유입되는 부유물 및 댐 퇴적물의 광물조성은 석영, 사장석, 녹니석, 일라이트이며 소량의 몬모릴로나이트와 캐올리나이트를 포함하고 있다. 안동댐 퇴적물과 다르게 임하댐 퇴적물에는 다량의 방해석을 포함하고 있다. 색도는 시료에 따라 약간의 차이가 있지만 회갈색에서 어두운 주황색 정도이다. 퇴적물의 중금속 농도는 안동댐이 임하댐보다 더 높다. 안동댐과 임하댐 퇴적물과 유입 부유물질의 주요 중금속 농도는 미국의 국립해양대기관리청의 기준을 적용할 경우 높은 오염도를 나타낸다. 안동댐 퇴적물의 중금속 농도가 임하댐보다 높은 것은 안동댐으로 유입되는 부유물질의 중금속 농도가 임하댐으로 유입되는 부유물질의 중금속 농도보다 높기 때문이다.

Arsenic is among the heavy metals commonly found in aqueous environments. Iron oxide is known as an efficient adsorbent for the arsenic. A new synthetic method was applied to provide iron oxide giving a large specific surface area. The mixing method affects the formation of iron oxide. Ultrasonic waves assisted the formation of very fine iron oxide in an organic phase. The synthesized iron oxide is amorphous type with a high surface area of more than 181.3 m2/g. Sorption capacity of the synthesized adsorbent was relatively very high for arsenic and varied depending on the oxidation state of arsenic: a higher capacity was obtained with As(V). Lower solution pH provided a higher sorption capacity for As(V). The competitive effect of co-exist anions such as chloride, nitrate, and sulfate was minimal in sorption capacity of the iron oxide for arsenic.

During the past few decades, significant increase in the consumption of coffee has led to rapid increase in the production of coffee waste in South Korea. Spent coffee waste is often treated as a general waste and is directly disposed without the necessary treatment. Spent Coffee Grounds (SCGs) can release several organic contaminants, including caffeine. In this study, leaching tests were conducted for SCGs and oxidative degradation of caffeine were also conducted. The tested SCGs contained approximately 4.4 mg caffeine per gram of coffee waste. Results from the leaching tests show that approximately 90% of the caffeine can be extracted at each step during sequential extraction. Advanced oxidation methods for the degradation of caffeine, such as UV/H2O2, photo-Fenton reaction, and UV/O3, were tested. UV radiation has a limited effect on the degradation of caffeine. In particular, UV-A and UV-B radiations present in sunlight cause marginal degradation, thereby indicating that natural degradation of caffeine is minimal. However, O3 can cause rapid degradation of caffeine, and the values of pseudo-first order rate constants were found to be ranging from 0.817min-1 to 1.506 min-1 when the ozone generation rate was 37.1 g/m3. Additionally, the degradation rate of caffeine is dependent on the wavelength of irradiation.

Trains have been a major means of transport in Korea during these past decades. However, train facilities such as stations and repair shops are contaminated with organic and inorganic substances. There is a high probability of train facility contamination with polyaromatic hydrocarbons (PAHs). This study evaluated the PAH and heavy metal contamination of soil near railroads in the Kyungpook area. A total of 18 soil samples were collected from the railroads and analyzed for 16 PAHs and 6 heavy metal species. The contamination level of the top soil was found to be slightly higher than that of the subsoil for contamination with PAHs. The ratio of carcinogenic PAH concentration to the total PAH concentration was relatively high, with a maximum of 0.9. The toxicity equivalent (TEQ) of the PAHs were 500.6 ng/kg in the topsoil and 355.5 ng/kg in the subsoil. The ratio of low molecular PAHs (LPAHs) to high molecular PAHs (LPAHs) ranged from 6.7 to 29.5; this shows that contamination is primarily due to combustion of fuel rather than due to petroleum. The ratio of phenanthrene to anthracene and the ratio of fluoranthene to pyrene also show that contamination occurred due to combustion for transportation. The heavy metal contamination level was lower than the Korean standard, but higher than the background concentration; this indicates that the soil was affected by the operation of the railways.

Recently, the demand for seismic retrofitting has risen rapidly due to the increasing risk of collapse of existing reinforced concrete columns due to the subsequent occurrence of the Gyeon-gju earthquake and the Po-hang earthquake in Korea. In the existing seismic retrofitting method, there are many seismic retrofitting methods such as steel plate reinforcement, fiber reinforcement, and cross-sectional enlargement, but there is a need for an improved method in terms of workability, economic feasibility, durability and maintenance. Therefore, seismic strengthening method of rectangular shaped RC column using rapid fastening of steel bars on the outside of the column is proposed, and the seismic evaluation of the proposed method is investigated through experiments.

오늘날 공동주택단지는 주거환경 수준의 향상과 주거 라이프 스타일의 변화, 이웃 간의 교류, 여가생활 증대, 건강에 대한 관심증대 등 다양한 사회문화적 현상으로 인해 변화되고 있다. 주거환경의 변화로 외부공간에 대한 필요성이 높아지고 있다. 공동주택단지 외부공간은 공동주택의 주거형태 특성상 이웃과의 교제가 부족한 환경과 단위주호 내에서 해결할 수 없는 문제점 등을 해결할 수 있으며 사회적 관계 증진과 공동체 의식 함양을 이끌 수 있는 중요한 공간이다. 이에 본 연구는 서울에 위치한 최근 완공된 공동주택단지를 대상으로 외부공간을 운동시설, 휴게시설, 놀이시설, 조경시설, 위생시설로 구 분하여 사례조사 하였으며 주민들의 커뮤니티시설로서 공간계획특성 및 디자인특성을 분석하였다. 조사결과에 따르면 운동시설의 경우 다양한 종류의 시설이 계획되어있는 반면 놀이시설이나 휴게시설은 단지별 차이가 없이 획일적인 형태로 계획되어 있어 거주자의 다양한 특성이 고려되어 있지 않았다. 특히 각 기능별 시설이 독립적으로 배치된 경우가 많아 복합적인 커뮤니티 공간으로서 거주자들의 교류를 도모할 수 있는 배치계획이 부족한 것으로 조사되어 서로 연계성 있게 계획 할 필요가 있는 것으로 나타났다. 향후 이웃과의 활발한 소통을 위한 공동주택단지 외부공간의 계획시 디자인 기초자료로 제공될 수 있을 것이다.