Sorption and Desorption Kinetics of Naphthalene and Phenanthrene on Black Carbon in Sediment

오상화,송동익,신원식,Oh, Sang-Hwa,Wu, Qi,Song, Dong-Ik,Shin, Won-Sik Korean Society of Soil and Groundwater Environment 2011 지하수토양환경 Vol.16 No.6

Black carbon (BC), a kind of high surface area carbonaceous material (HSACM), was isolated from Andong lake sediment. Sorption and desorption kinetics of naphthalene (Naph) and phenanthrene (Phen) in organic carbon (OC) and BC in the Andong lake sediment were investigated. Several kinetic models such as one-site mass transfer model (OSMTM), two-compartment first-order kinetic model (TCFOKM), and a newly proposed modified two-compartment first-order kinetic model (MTCFOKM) were used to describe the sorption and desorption kinetics. The MTCFOKM was the best fitting model. The MTCFOKM for sorption kinetics showed that i) the sorbed amounts of PAHs onto BC were higher than those onto OC, consistent with BET surface area; ii) the equilibration time for sorption onto BC was longer than those onto OC due to smaller size of micropore ($11.67{\AA}$) of BC than OC ($38.18{\AA}$); iii) initial sorption velocity of BC was higher than OC; and iv) the slow sorption velocity in BC caused the later equilibrium time than OC even though the fast sorption velocity was early completed in both BC and OC. The MTCFOKM also described the desorption of PAHs from the OC and BC well. After desorption, the remaining fractions of PAHs in BC were higher than those in OC due to stronger PAHs-BC binding. The remaining fractions increased with aging for both BC and OC.

Na₂S를 이용한 EDTA 토양세척수로부터의 중금속 분리

오상화,신원식,Oh, Sanghwa,Shin, Won Sik 한국지하수토양환경학회 2015 지하수토양환경 Vol.20 No.7

Soil washing with ethylenediaminetetraacetic acid (EDTA) is highly effective in the remediation of soils contaminated with heavy metals. The EDTA recycling process is a requisite for reducing the operating cost. The applicability of Na₂S addition on the precipitation of heavy metals from the spent soil washing solution and thereby recycling of EDTA was investigated. Addition of Na₂S into the single metal-EDTA and the mixed metal-EDTA solutions ([Na₂S]/[metal-EDTA] ratio = 30, reaction time = 30 min and pH = 7~9) was highly effective in the separation of Cu and Pb from metal-EDTA complexes, but not for Ni. The Zn removal efficiency varied with pH and slightly increased upto 40% as the reaction time increased from 0 to 240 min which was longer than those for Cu and Pb. Ca(OH)₂ was subsequently added to induce further precipitation of Zn and Ni and to reduce the Na₂S dose. At the [Na₂S]/[metal-EDTA] ratio of 10, the removal efficiencies of all heavy metals excluding Ni were above 98% with the dose of Ca(OH)₂ at 0.002, 0.006 and 0.008 g into 100 mL of Cu-, Pb- and Zn-EDTA solutions, respectively. However, Ca(OH)₂ addition was not effective for Ni-EDTA solution. A further research is needed to improve metal removal efficiency and subsequent EDTA recycling for the real application in field-contaminated soils.

Na2S를 이용한 EDTA 토양세척수로부터의 중금속 분리

오상화,신원식 한국지하수토양환경학회 2015 지하수토양환경 Vol.20 No.7

Soil washing with ethylenediaminetetraacetic acid (EDTA) is highly effective in the remediation of soils contaminated with heavy metals. The EDTA recycling process is a requisite for reducing the operating cost. The applicability of Na2S addition on the precipitation of heavy metals from the spent soil washing solution and thereby recycling of EDTA was investigated. Addition of Na2S into the single metal-EDTA and the mixed metal-EDTA solutions ([Na2S]/[metal-EDTA] ratio = 30, reaction time = 30 min and pH = 7~9) was highly effective in the separation of Cu and Pb from metal-EDTA complexes, but not for Ni. The Zn removal efficiency varied with pH and slightly increased upto 40% as the reaction time increased from 0 to 240 min which was longer than those for Cu and Pb. Ca(OH)2 was subsequently added to induce further precipitation of Zn and Ni and to reduce the Na2S dose. At the [Na2S]/[metal-EDTA] ratio of 10, the removal efficiencies of all heavy metals excluding Ni were above 98% with the dose of Ca(OH)2 at 0.002, 0.006 and 0.008 g into 100 mL of Cu-, Pb- and Zn-EDTA solutions, respectively. However, Ca(OH)2 addition was not effective for Ni-EDTA solution. A further research is needed to improve metal removal efficiency and subsequent EDTA recycling for the real application in field-contaminated soils.

광미내 Zn의 탈착 특성과 지렁이에 대한 생이용성

오상화,신원식,Oh, Sang-Hwa,Shin, Won-Sik 한국지하수토양환경학회 2011 지하수토양환경 Vol.16 No.4

Sorption and sequential desorption experiments were conducted for Zn using a natural soil (NS) in background status by aging (1, 30 and 100 days). The sorption isotherm showed that Zn had high sorption capacity but low sorption affinity in NS. Sequential desorption was biphasic with appreciable amount of sorbed Zn residing in the desorption-resistant fraction after several desorption steps. The biphasic desorption behavior of Zn was characterized by a biphasic desorption model that includes a linear term to represent labile or easily-desorbing fraction and a Langmuirian-type term to represent desorption-resistant fraction. The biphasic desorption model indicated that the size of the maximum capacity of desorption-resistant fraction ($q^{irr}_{max}$) increased with aging in NS. Desorption kinetics and desorption-resistance of Zn in the soils collected from mine tailings (MA, MB and MC collected from surface, subsurface soils and mine waste, respectively) were investigated and compared to the bioavailability to earthworm (Eisenia fetida). Desorption kinetic data of Zn were fitted to several desorption kinetic models. The ratio ($q_{e,d}/q_0$) of remaining Zn at desorption equilibrium ($q_{e,d}$) to initial sorbed concentration ($q_0$) was in the range of 0.53~0.90 in the mine tailings which was higher than that in NS, except MA. The sequential desorption from the mine tailings with 0.01M Na$NO_3$ and 0.01M $CaCl_2$ showed that appreciable amounts of Zn are resistant to desorption due to aging or sequestration. The SM&T (Standard Measurements and Testing Programme of European Union) analysis showed that the sum of oxidizable (Step III) and residual (Step IV) fractions of Zn was linearly related with its desorption-resistance ($q^{irr}_{max}$) determined by the sequential desorption with 0.01M Na$NO_3$ ($R^2$= 0.9998) and 0.01M $CaCl_2$ ($R^2$= 0.8580). The earthworm uptake of Zn and the desorbed amount of Zn ($q_{desorbed}$ = $q_0-q_{e,d}$) in MB soil were also linearly related ($R^2$ = 0.899). Our results implicate that the ecological risk assessment of heavy metals would be possible considering the relation between desorption behaviors and bioavailability to earthworm.

대중매체 소비가 여대생의 신체변형에 대한 태도 및 행동에 미치는 영향과 그 매개 과정

오상화,나은영 한국소비자·광고심리학회 2002 한국심리학회지 소비자·광고 Vol.3 No.2

어휘 교육 방법 변화의 필요성과 개선방안 연구

오상화 ( Sang Hwa Oh ) 고려대학교 한국어문교육연구소 2014 한국어문교육 Vol.16 No.-

이 연구는 어휘 교육이 단순 단어 교육 및 뜻풀이 교육으로 축소되어 교수되고 있는 현재의 모습에 의문을 품고 진행되었다. 그리고 어휘가 교육적인 관점에서 학습자들에게 좀 더 유의미하게 접근할 수 있어야 한다는 전제 아래 논의를 진행하였다. 이전의 어휘 교육과 현재의 어휘 교육을 토대로 앞으로의 어휘 교육 방법이 변화하여야 함을 밝히기 위하여 어휘 교육이 걸어온 길을 시기와 교육과정으로 구분하여 이들이 어떠한 모습을 하고 있었는지를 살피었다. 그리고 어휘를 어떻게 바라보아야 하는지와 현재의 어휘 교육이 개선되어야 하는 방향을 생각하여 보았다. 어휘 교육은 어휘의 정의에서부터 인식의 변화가 필요하다. 어휘를 ‘단어들의 집합’ 수준으로만 보아서는 안 되며, 어휘 교육의 방향은 학습자의 어휘력 신장을 도모하여 국어 사용 능력의 향상을 꾀하는 방향으로 나아갈 수 있어야 한다. 또한 교수자와 학습자 모두 어휘를 부수적인 것으로 파악하는 도구적 관점에서 벗어나야 한다. 도구적 관점에서 인지적 관점으로 변화할 때에 올바른 어휘 교육과 학습이 이루어질 수 있다. 그리고 이러한 변화의 필요성을 정확히 인식할 때 현재의 어휘 교육 방법이 더 나은 길로 나아갈 수 있다. This study was carried out calling the present form of teaching vocabulary reduced to simple teaching and definition of words into question. Also, a discussion was carried out under a premise that learners should be able to approach vocabulary in a more significant way from an educational viewpoint. To find out that the future teaching vocabulary should change based on previous teaching vocabulary and present teaching vocabulary, the paths that teaching vocabulary followed were divided by period and curriculum to inquire into what they looked like. Also, this study considered how vocabulary should be viewed and the direction in which the present teaching vocabulary should improve. Teaching vocabulary needs changes in perception from the definition of it. Vocabulary should not be viewed just on a level of ‘sets of words,’ and it should be taught in a direction of attempting to promote learners`` vocabulary and improve their ability to use Korean. In addition, both teachers and learners should break away from an instrumental viewpoint of considering vocabulary incidental. Right teaching and learning vocabulary can be achieved only if they are changed from an instrumental viewpoint to cognitive one. Also, correct awareness of this need for change can lead the present method of teaching vocabulary to a better way.

Modified Two-Compartment First-Order Kinetic Model (MTCFOKM)을 이용한 퇴적물에 대한 Ibuprofen의 빠른 및 느린 수착의 동력학 해석

오상화 ( Sang Hwa Oh ) 한국수처리학회 2015 한국수처리학회지 Vol.23 No.5

Ibuprofen is a nonsteroideal anti-inflammatory drug (NSAID) widely used as a pain reliever and therefore, has been frequently detected in rivers, lakes and even their sediments. However, few data have been available for the fate of ibuprofen in the water/sediment compartment despite its high pKow (=3.5). This study focused on the dynamic sorption of ibuprofen onto sediment at pH 4 and 0 and 30 ppt (part per thousand) of salinity. Experimental data were fitted to several kinetic models such as one-site mass transfer model (OSMTM), pseudo-first order kinetic model (PFOKM), pseudo-second order kinetic model (PSOKM), two compartment first order kinetic model (TCFOKM), and modified two compartment first order kinetic model (MTCFOKM). The MTCFOKM was the best in fitting sorption data (R2 > 0.991 and 0.985 at 0 and 30 ppt salinity, respectively). The MTCFOKM can fit the data into the fast and slow sorption kinetics. The results show that the fast sorption of ibuprofen finished within 1 day, whereas the slow sorption finished between 10 and 100 days. Salinity increases the sorbed amount of ibuprofen (qe) and affects also the finish time for the fast and slow sorption. The increase in salinity decreased the finish time for the fast sorption whereas increased it for the slow sorption.

실리콘 튜빙 담지 폴리우레탄 생물벽체를 이용한 지하수내 질산성 질소 제거

오상화 ( Sanghwa Oh ),신원식 ( Won Sik Shin ) 한국수처리학회(구 한국수처리기술연구회) 2018 한국수처리학회지 Vol.26 No.1

A column reactor with biobarrier consisting of polyurethane-activated carbon (PU-AC) media with hollow silicon tubing coiled inside the media was operated to estimate the potential for treatment of nitrate-contaminated groundwater. The tubing was also evaluated for its potential to provide carbon sources such as glucose, methanol, ethanol, and acetic acid for denitrification process. Methanol was selected as the most effective carbon because the highest amount of methanol could be delivered with appropriate releasing rate. In a column experiment, the groundwater containing 60 mg/L of nitrate was flowed through the PU-AC biobarrier. Denitrification of NO₃ ^- coupled to carbon supply throughout the silicon tubing was successfully observed, depending on the groundwater velocity and methanol concentration. For satisfying potable groundwater criteria of nitrate (10 mg/L), 0.033 cm/min of groundwater velocity with 3% of methanol content in silicon tubing was appropriate corresponding to negative ORP value of -240 mV during denitrification. To deduce the optimum operating condition of the column reactor, the groundwater velocity was further reduced to 0.018 cm/min and the carbon content (%) was changed from 2.0 to 3.5% in the silicon tubing, which resulting in 3.5% of the optimum value (approximately 83% of NO₃-N removal). At this point, the ORP showed all negative values, indicating that ORP can be used as an indicator of denitrification in biobarrier in field.

경기도 (京畿道) 선사시대 (先史時代) 유적지명표 (遺蹟地名表)

오상화 ( Sang Hwa Oh ) 고려대학교 역사연구소 1961 사총 Vol.6 No.-

청소년의 인터넷 이용에 미치는 부모의 동기부여 언어 사용의 영향과 목표지향성의 매개 역할

오상화(Sang-Hwa Oh),나은영(Eun-Yeong Na) 한국언론학회 2009 한국언론학보 Vol.53 No.2