https://repository.kopri.re.kr/handle/201206/9760 Thu, 23 Apr 2026 14:41:08 GMT 2026-04-23T14:41:08Z https://repository.kopri.re.kr/handle/201206/10425 Title: Modeling the Sources and Chemistry of Polar Tropospheric Halogens (Cl, Br, and I) Using the CAM­Chem Global Chemistry­Climate Model Authors: Fernandez, Rafael P.; Carmona­Balea, Antia; Cuevas, Carlos A.; Barrera, Javier A.; Kinnison, Douglas E.; Lamarque, Jean-­Francois; Blaszczak-­Boxe, Christopher; Kim, Kitae; Choi, Wonyong; Hay, Timothy; Blechschmidt, Anne­-Marlene; Schonhardt, Anja; Burrows, John P.; Saiz-­Lopez, Alfonso Abstract: Current chemistry climate models do not include polar emissions and chemistry of halogens.This work presents the first implementation of an interactive polar module into the very short­lived (VSL) halogen version of the Community Atmosphere Model with Chemistry (CAM­Chem) model. The polar module includes photochemical release of molecular bromine, chlorine, and interhalogens from the sea­ice surface, and brine diffusion of iodine biologically produced underneath and within porous sea­ice. It also includes heterogeneous recycling of inorganic halogen reservoirs deposited over fresh sea­ice surfaces and snow­covered regions. The polar emission of chlorine, bromine, and iodine reach approximately 32, 250, and 39 Gg/year for Antarctica and 33, 271, and 4 Gg/year for the Arctic, respectively, with a marked seasonal cycle mainly driven by sunlight and sea­ice coverage. Model results are validated against polar boundary layer measurements of ClO, BrO, and IO, and satellite BrO and IO columns. This validation includes satellite observations of IO over inner Antarctica for which an iodine "leapfrog" mechanism is proposed to transport active iodine from coastal source regions to the interior of the continent. The modeled chlorine and bromine polar sources represent up to 45% and 80% of the global biogenic VSLCl and VSLBr emissions,respectively, while the Antarctic sea­ice iodine flux is ~10 times larger than that from the Southern Ocean.We present the first estimate of the contribution of polar halogen emissions to the global tropospherichalogen budget.CAM­Chem includes now a complete representation of halogen sources and chemistry from pole­to­pole and from the Earth's surface up to the stratopause. Thu, 01 Aug 2019 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/10425 2019-08-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/9661 Title: Titanium dioxide surface modified with both palladium and fluoride as an efficient photocatalyst for the degradation of urea Authors: Kim, Hyoung-il; Kim, Kitae; Park, Soona; Kim, Wooyul; Kim, Seungdo; Kim, Jungwon Abstract: TiO2 surface modified with both Pd nanoparticles and fluorides (F-TiO2/Pd) was prepared and applied as a photocatalyst in the degradation of urea. Various surface analysis techniques, including X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy, and energy-dispersive X-ray spectroscopy, were used to verify the coexistence of Pd nanoparticles and fluorides on the surface of TiO2 in F-TiO2/Pd. F-TiO2/Pd showed a higher photocatalytic activity than those of bare TiO2 and single-component-modified TiO2 photocatalysts such as fluorinated TiO2 (F-TiO2) and Pd-loaded TiO2 (Pd/TiO2). The higher urea degradation efficiency of F-TiO2/Pd is ascribed to the enhanced production of hydroxyl radicals (●OH) by the synergistic action of the surface Pd and fluoride. Pd nanoparticles and fluorides facilitate the transfer of valence band holes (hvb+) and their reaction with water molecules, respectively, synergistically enhancing the production of ●OH. The photocatalytic activity of F-TiO2/Pd for the degradation of urea increased upon increasing the fraction of the fluorinated TiO2 surface, which is higher at higher fluoride concentrations and lower pH. Although Pt/TiO2 showed higher photocatalytic activity for the degradation of urea than those of Pd/TiO2 and Au/TiO2, the strong positive effect of fluoride complexation was only exhibited by Pd/TiO2 (a slight positive effect and a negative effect were observed for Au/TiO2 and Pt/TiO2, respectively). As a result, the degradation of urea proceeded more rapidly in a UV-irradiated suspension of F-TiO2/Pd than when any of other photocatalysts (i.e., bare TiO2, Pd/TiO2, F-TiO2, Au/TiO2, F-TiO2/Au, Pt/TiO2, and F-TiO2/Pt) were used under the same conditions. The first-order degradation rate constants (k) of urea depending on the type of TiO2 were as follows: 0.097 h？1 for bare TiO2, 0.158 h？1 for Pd/TiO2, 0.151 h？1 for F-TiO2, 0.351 h？1 for F-TiO2/Pd, 0.173 h？1 for Au/TiO2, 0.223 h？1 for F-TiO2/Au, 0.240 h？1 for Pt/TiO2, and 0.165 h？1 for F-TiO2/Pt, respectively. In addition, F-TiO2/Pd proved to be stable in repeated urea degradation cycles. Sat, 01 Jun 2019 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/9661 2019-06-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/9641 Title: Nitrite-Induced Activation of Iodate into Molecular Iodine in Frozen Solution Authors: Kim, Kitae; Ju, Jinjung; Kim, Bomi; Chung, Hyun Young; Vetrakova, L'ubica; Heger, Dominik; Saiz-Lopez, Alfonso; Choi, Wonyong; Kim, Jungwon Abstract: A new mechanism for the abiotic production of molecular iodine (I2) from iodate (IO3？), which is the most abundant iodine species, in dark conditions was identified and investigated. The production of I2 in aqueous solution containing IO3？ and nitrite (NO2？) at 25 °C was negligible. However, the redox chemical reaction between IO3？ and NO2？ rapidly proceeded in frozen solution at ？20 °C, which resulted in the production of I2, I？, and NO3？. The rapid redox chemical reaction between IO3？ and NO2？ in frozen solution is ascribed to the accumulation of IO3？, NO2？, and protons in the liquid regions between ice crystals during freezing (freeze concentration effect). This freeze concentration effect was verified by confocal Raman microscopy for the solute concentration and UV？visible absorption spectroscopy with cresol red (acid-base indicator) for the proton concentration. The freezing-induced production of I2 in the presence of IO3？ and NO2？ was observed under various conditions, which suggests this abiotic process for I2 production is not restricted to a specific region and occurs in many cold regions. NO2？-induced activation of IO3？ to I2 in frozen solution may help explain why the measured values of iodine are larger than the modeled values in some polar areas. Wed, 01 May 2019 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/9641 2019-05-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/9642 Title: Hydrochemical characteristics of groundwater and stream water in a karst area of Samcheok, Korea Authors: Ryu, hansun; Lee, Jin-Yong; 임, 충완; Kim, Kitae Abstract: 본 연구에서는 강원도 삼척시 카르스트 지역의 하천수와 지하수의 수화학적 진화에 대하여 평가하였다. 연구지역의 하천수와 지하수는 높은 농도의 칼슘과 중탄산이온 농도를 보였는데 이는 주로 탄산염암 중 석회암의 용해에 의한 결과이다. 탄소동위원소와 이온비에 의하면 이 지역의 수화학은 주로 탄산염암 용해 그리고 일부 대기 중 이산화탄소 용해에 영향을 받음을 지시하였다. 특별히 바다 근처의 하천수는 높은 농도의 나트륨과 염소이온 농도를 보였다. 산소 및 수소 안정동위원소의 조성과 나트륨과 염소이온의 이온비를 살펴보면 이 지역의 하천수는 전형적인 편서풍에 의한 서해안 해수증발에서 유래한 것보다는 인근 동해안 해수의 증발에 기원임을 지시하였다. This study examines the chemical evolution of stream water and groundwater in the karst area of Samcheok city. The stream water and groundwater in this area are characterized by high levels of Ca2+ and HCO3-, which is a result of water-carbonate rock interaction, especially calcite dissolution. The δ18C and ionic ratios also indicates carbonate rock dissolution is a dominant factor controlling the water chemistry in this area with a small contribution of atmospheric CO2 dissolution. The coastal stream water was highly affected by seawater, showing high concentrations of Na+ and Cl-. The stable isotopic compositions (δD and δ18O) and ionic ratios of Na+ and Cl- indicate that the stream water is originated from a single source, nearby seawater evaporation from East Sea rather than typical evaporation of Yellow Sea, transported by the prevailing westerlies. Fri, 01 Feb 2019 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/9642 2019-02-01T00:00:00Z