• Advances in environmental research
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• 제3권1호
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• pp.29-43
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• 2014

Pharmaceutical wastewater effluents are well known for their difficult elimination by traditional biotreatment methods and their important contribution to environmental pollution due to its fluctuating and recalcitrant nature. OTC is one of the nonbiodegradable antibiotics that makes antibiotic-resistant, so it can make be high risk for environment. NZVI can be a good choice for removal of OTC in aqueous solution. Response surface methodology (RSM) was used to optimize the amounts of NZVI and OTC to be used at pH 3 and under 200 W, UV-A irradiation. The responses were removal percent of absorption at 290 and 348 nm, TOC and COD of OTC. In the optimum condition, Linear model was performed 155 ppm of OTC were removed by 1000 ppm NZVI after 6.5 hours and the removal efficiency of absorption at 290 and 348 nm, TOC and COD were 87, 95, 85 and 89 percent, respectively. In the similar process, there is no organic compound after 14 hours. The parameters ORP, DO and pH were investigated for 6:30 hours to study the type of NZVI reaction in process. In the beginning of reaction, oxidation was the dominant reaction after 3 hours, photocatalytic reaction was remarkable. The mechanism of OTC degradation is proposed by HPLC/ESI-MS and four by products were found. Also the rate constants (first order kinetic chain reaction model) were 0.0099, 0.0021, 0.0010, 0.0049 and $0.0074min^{-1}$, respectively.

• 한국가시화정보학회지
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• 제20권3호
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• pp.67-73
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• 2022

Underwater environmental pollution caused by microplastic particles is considered to be one of the most serious problems in many oceans and countries nearby. Previous academic studies or field technologies tried to remove the micro-sized particles are often energy-consuming and costly, so it is hard to be employed for the actual uses. In this study, the mechanism of removal of micro-sized polyethylene spheres (size in order of 100㎛) using a rising bubble is experimentally investigated. It is found that the particles are either affected by bubble wake, thus translocated close to the water surface, or pushed far away by the surrounding fluid flow, depending on their initial position relative to the bubble. By scrutinizing the visualized behaviors of bubble-particle interaction, we draw the governing parameter, i.e., the polar angle between the particle and the bubble, to determine the effective capturing of the particles with a rising bubble.

• Korean Chemical Engineering Research
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• 제50권6호
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• pp.980-987
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• 2012

비점오염원은 세정에 의해 하수관 내로 유입되어 수계까지 흘러 수계의 오염부하를 가중시킬 뿐만 아니라, 관의 상태에 따라 누수 및 월류를 야기하여 오염을 일으킨다. 이에 따라 하수관거의 유지관리 및 환경오염 방지를 위한 관거내 하수의 유량, 수질, 불명수 및 월류 등을 효율적으로 관리하기 위한 모니터링의 필요성이 증가하고 있다. 그러나 하수관거의 경우, 지하에 설계되며 그 구조 및 연결이 복잡한 특성으로 인해 실제 하수관거에 대한 모니터링은 쉽지 않다. 본 연구에서는 시스템해석이론에 기초한 하수관망 오염제거 해석과 관망 모니터링 및 이상진단방법을 제시하였다. 먼저 하수관망 공정모사 프로그램인 Stormwater & Wastewater Management Model for expert (XP-SWMM)을 이용하여 관망 내의 오염물질의 거동패턴을 해석하였다. 둘째, 다변량 통계 모니터링을 이용하여 하수관망 내의 수질 모니터링 및 하수관망 유출을 탐지하는 관망 이상 진단을 수행하였다. 정적/동적 상태 시스템에 기초한 하수관망 오염 매카니즘 해석결과, 강우시 총질소와 총인 부하량이 비강우시보다 급격하게 증가함을 확인하였으며, 이는 수계의 오염부하를 가중시킬 것으로 판단되다. 이에 따라 하수관망 내 유출은 강우로 생긴 유량 및 유입오염물질의 농도 증가로 인한 관망이상으로 사료된다. 제안된 하수관망 모니터링 및 이상진단 기법은 도시 유역에서의 비점오염원 관리와 지속적인 모니터링에 있어 효과적으로 사용될 수 있을 것으로 예상된다.

• Environmental Engineering Research
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• 제20권1호
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• pp.33-39
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• 2015

Mercury is a toxic pollutants present in different types of industrial effluents and is responsible for environmental pollution. Removal of Hg(II) ions from synthetic wastewater was studied using the activated biocarbon produced from the leaves of Tridax procumbens (Asteraceae). The particle size of the biocarbon (BC) is in the range of $100-120{\mu}m$. The effects of initial metal ion concentration, pH, contact time, and amount of biocarbon on the biosorption process were studied at temperature of $28{\pm}2^{\circ}C$. Batch experimental studies showed that an equilibrium time of 160 min was required for the maximum removal of Hg(II) at the optimized biocarbon dose of 2.5 g per 100 mL of synthetic wastewater. The optimum pH required for maximum removal (96.5%) of Hg(II) ions was found to be 5.5. The biosorption of metal ions onto activated biocarbon surface is probably via an ion exchange mechanism. The biocarbon can be regenerated with minimum loss. Further, it can be reused without any chemical activation. The findings of the research suggested that, the biocarbon produced from cost effective renewable resources can be utilized for the treatment of industrial wastewater.

• 공업화학
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• 제28권6호
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• pp.685-690
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• 2017

암모니아는 현대 산업에서 빠질 수 없는 유용한 물질이다. 일반적으로 농업용 폐기물의 분해과정을 통해 배출되며 인체에 매우 해로운 독극물로 알려져 있다. 산업에서 흔하게 쓰이는 물질이기에 직접 누출이나 간접 누출로 인한 수질오염의 가능성이 있다. 이 경우 암모늄이온을 빠르게 제거하는 데는 제올라이트의 흡착능을 이용하는 것이 좋지만 흡착만으로는 충분히 제거할 수 없다. 본 논문에서는 상용 제올라이트의 흡착능을 통한 암모늄이온의 제거 효율과 미생물의 생물학적 메커니즘을 통한 제거효율을 비교하였다. 추가적으로 제올라이트에 미생물을 고정하여 화학적 흡착 및 생물학적 전환 기술을 병합하여 그 효율을 비교하였다. 그 결과 100 ppm 기준 상용 제올라이트의 경우 2-4 h 사이에 67-81%의 제거효율을 보이는데 반해 선정 미생물인 Klebsiella pneumoniae subsp. Pneumoniae를 이용한 경우 8 h 내에 최대 97%의 제거 효율을 나타냈었다. 그리고 미생물을 제올라이트에 고정시켰을 때 8 h 이내에 98.5%로 제거 효율 및 속도가 증가하는 것을 확인할 수 있었다.

• Advances in environmental research
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• 제3권2호
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• pp.163-172
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• 2014

Magnetite was chosen as a typical adsorbent to study its phosphate adsorption capacity in water body with low concentration of phosphorus (below $2mg\;PL^{-1}$). Magnetite was collected from Luoyang City, Henan Province, China. In this research, three factors have been studied to describe the adsorption of phosphate on magnetite, which was solution concentration (concentration ranging from 0.1 to $2.5mg\;PL^{-1}$), suspension pH (1 to 13) and temperature (ranging from $10^{\circ}C$ to $40^{\circ}C$). In addition, the modified samples had been characterized with XRD and FE-SEM image. The results show that iron ions contains in magnetite were the main factors of phosphorus removal. The behavior of phosphorus adsorption to substrates could be fitted to both Langmuir and Freundlich isothermal adsorption equations in the low concentration phosphorus water. The theoretical saturated adsorption quantity of magnetite is 0.158 mg/g. pH has great influence on the phosphorus removal of magnetite ore by adsorption. And pH of 3 can receive the best results. While temperature has little effect on it. Magnetite was greatly effective for phosphorus removal in the column experiments, which is a more practical reflection of phosphorous removal combing the adsorption isotherm model and the breakthrough curves. According to the analysis of heavy metals release, the release of heavy metals was very low, they didn't produce the secondary pollution. The mechanism of uptake phosphate is in virtue of chemisorption between phosphate and ferric ion released by magnetite oxidation. The combined investigation of the magnetite showed that it was better substrate for water body with low concentration of phosphorus.

• 한국대기환경학회지
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• 제8권1호
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• pp.45-51
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• 1992

A study on acidity in fog, dew and frost was carried out. Samples were taken during May 1990-February 1991 at two sites in Chongwon, Choongbook. The acidity of dew and of fog collected from grass at site A was 4.89 and 5.46, respectively. Dew in summer showed very strong acidity. The volume of dew deposited on grass was much less than the volume of rain, but dew is effective to diffuse acid predursors and acid materials. Dew and fog can remove more effectively atmospheric acid materiasl deoposited on grass by diurnal turbulent motion rather than direct absorption of acid predursors and materials in the atmosphere. In a polluted area, acidic dew and fog can be occurred by the direct absorption and oxidation of acidic predursors in the atmosphere as well as the role of wet removal on grass surface. Acidity of frost collected on teflon surface showed little difference to acidity of dew and fog on teflon surface. This suggests a similar absorption mechanism of atmospheric precursors and materials into dew and frost in the atmosphere. Strong acidity in dew, fog and frost appeared to occur from local pollution sources of several ten kilometres. In particular, strong acidity in dew, fog, and frost together with acid rain can accelerate a damage in ecosystems. Discussion is made on scientific analyses and seasonal variations of acidity of fog, dew and frost. A mechanism on acidification of fog, dew and frost is also discussed.

• 한국분무공학회지
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• 제12권2호
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• pp.86-93
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• 2007

There is a growing interest to develop an eco-friendly air cleaner with high performance through a remanufacturing process. Two kinds of polyurethane filter media, a coarse (Filter-A) and a fine filter media (Filer-B), are used in this study to protect a vehicle engine from airborne particles. In order to improve the collection performance of the filters (Filter-A, Filter-B), an oil coating technology on the filter surface was introduced. As a result, inertial force is a dominant collection mechanism for a dry filter media, so that collection efficiency increases with increasing filtration velocity. However, intra-structure change of an oil-coated filter media influences on the collection mechanism, which shows a non-linear collection efficiency curve in terms of filtration velocity. The result shows that the developed filter media are eco-friendly and effective to protect a vehicle engine from airborne particles especially at low filtration velocity.

• 한국도로학회논문집
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• 제16권5호
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• pp.49-58
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• 2014

PURPOSES : In areas of high traffic volume, such as expressway across large cities, the amount of nitrogen oxides (NOx) emitted into the atmosphere as air pollution can be significant since NOx gases are the major cause of smog and acid rain. Recently, the importance of NOx removal has arisen in the world. Titanium dioxide ($TiO_2$), that is one of photocatalytic reaction material, is very efficient for removing NOx. The NOx removing mechanism of $TiO_2$ is the reaction of solar photocatalysis. Therefore, $TiO_2$ in road structure concrete need to be contacted with ultraviolet rays (UV) to be activated. In general, $TiO_2$ concretes are produced by replacement of $TiO_2$ as a part of concrete binder. However, considerable portion of $TiO_2$ in concrete cannot contact with the pollutant in the air and UV. Therefore, $TiO_2$ penetration method using the surface penetration agents is attempted as an alternative in order to locate $TiO_2$ to the surface of concrete structure. METHODS : This study aimed to evaluate the NOx removal efficiency of photocatalytic concrete due to various $TiO_2$ application method such as mix with $TiO_2$, surface spray($TiO_2$ penetration method) on hardened concrete and fresh concrete using surface penetration agents. The NOx removal efficiency of $TiO_2$ concrete was confirmed by NOx Analyzing System based on the specification of ISO 22197-1. RESULTS : The NOx removal efficiency of mix with $TiO_2$ increased from 11 to 25% with increasing of replacement ratio from 3 to 7%. In case of surface spray on hardened concrete, the NOx removal efficiency was about 50% due to application amount of $TiO_2$ with surface penetration agents as 300, 500 and 700g/m2. The NOx removal efficiency of surface spray on fresh concrete due to all experimental conditions, on the other hand, which was very low within 10%. CONCLUSIONS : It was known that the $TiO_2$ penetration method as surface spray on hardened concrete was a good alternative in order to remove the NOx gases for concrete road structures.

• Nuclear Engineering and Technology
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• 제54권2호
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• pp.456-461
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• 2022

Heavy metal pollution is caused due to anthropogenic activities and is considered as a serious environmental problem which endangers human health and environment. The present study deals with biosorption, an eco-friendly technique for the removal of heavy metal Zn(II) from aqueous medium. Various natural materials have been explored for the uptake of metal ions, where most of them are physically or chemically enhanced. Dry cowdung powder (DCP) has been utilized as a low-cost, environmentally friendly humiresin without any pre-treatment, thus demonstrating the concept of Green Chemistry. Batch biosorption studies using ⁶⁵Zn(II) tracer were performed and the impact of different experimental parameters was studied. Results revealed that at pH 6, 94 ± 2% of Zn(II) was effectively biosorbed in 5 min, at 303 K. The process was spontaneous and exothermic, following pseudo-second-order reaction. The mechanism of heavy metal biosorption employing green adsorbent was therefore elucidated in order to determine the optimal method for removing Zn(II) ions. DCP has a lot of potential in the wastewater treatment industry, as seen by its ability to meet 3A's affordability, adaptability, and acceptability criteria. As a result, DCP emerges as one of the most promising challengers for green chemistry and the zero-waste idea.