• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.8 no.3
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• pp.317-326
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• 2003

In order to improve our knowledge of the characteristics of organic compounds in coastal waters, water samples were collected from the Incheon coastal region, the Hyungsan River in Youngil Bay and the Busan coastal region. Also, mooring was carried out near the Kanghwa Island and Seo Island. In this study, the relationship between the total organic carbon (TOC) and salinity, chemical oxygen demand (COD) and salinity were evaluated and determined. Riverine end-member of TOC into the Korean coastal area and its COD estimated from these relationships were 5.32 mg C/l and 8.87 mg O$_2$/l, respectively. The oxidation efficiency of COD to TOC estimated using the high-temperature catalytic oxidation method was about 47％. The linear relationship between TOC and COD was derived as COD (mg O$_2$/l)=0.61${\times}$TOC (mg C/l) -0.03, (R$^2$=0.66). Therefore, it is possible to estimate total organic carbon using this equation from previously reported chemical oxygen demand.

• YAKHAK HOEJI
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• v.22 no.3
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• pp.157-162
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• 1978

Total organic carbon(TOC) can be determined by means of combustion and flame ionization detector. The principle of string method is that a sample acidified to pH2 and transferred into combustion tube by string is oxidized with air. Another combustion tube method is that organic compounds are oxidized in the combustion tube charged with CuO and cobalt asbestos after the acidified sample is injected directly by microsyringe. Carbon dioxide evolved was reduced under specially treated nickel catalyst and hydrogen, the methane produced was detected by flame ionization detector. Linear relationship was found between concentration and the peak height by the string method. The peak area in the case of combustion tube method is in the range of 1-200ppm. The coefficient of variation by string method was 2.3% and that by combustion tube method was 1.8%. The lower detectable limit was about 10mol. Advantages of the latter are simplicity, sensitivity and reproducibility. TOC in contineous stream can also be determined automatically by means of the string method.

• Journal of Korean Society for Atmospheric Environment
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• v.31 no.6
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• pp.497-507
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• 2015

Real-time and quantitative measurement of the chemical composition in ambient aerosols represents one of the most challenging problems in the field of atmospheric chemistry. In the present study, time resolved application by Aerosol-into-Mist System (AIMS) following by total organic carbon analyzer (TOC) has been developed. The unique aspect of the combination of these two techniques is to provide quantifiable water soluble organic carbon (WSOC) information of particle-phase organic compounds on timescales of minutes. We also demonstrated that the application of the AIMS method is not limited to water-soluble organic carbon but inorganic ion compounds. By correlating the volume concentrations by optical particle sizer (OPS), water soluble organic carbon can be highly related to the secondary organic products. AIMS-TOC method can be potentially applied to probe the formation and evolution mechanism of a variety of SOA behaviors in ambient air.

• Environmental Engineering Research
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• v.25 no.4
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• pp.488-497
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• 2020

The present study investigates the feasibility of nitrogenous heterocyclic compounds (NHCs) (Pyridine-Quinoline) degradation by catalytic wet peroxidation (CWPO) in the presence of nanoscale zerovalent iron supported on granular activated carbon (nFe⁰/GAC) using statistical optimization technique. Response surface methodology (RSM) in combination with Box-Behnken design (BBD) was used to optimize the process parameters of CWPO process such as initial pH, catalyst dose, hydrogen peroxide dose, initial concentration of pyridine (Py) and quinolone (Qn) were chosen as the main variables, and total organic carbon (TOC) removal and total Fe leaching were selected as the investigated response. The optimization of process parameters by desirability function showed the ~85% of TOC removal with process condition of initial solution pH 3.5, catalyst dose of 0.55 g/L, hydrogen peroxide concentration of 0.34 mmol, initial concentration of Py 200 mg/L and initial concentration of Qn 200 mg/L. Further, for TOC removal the analysis of variance results of the RSM revealed that all parameter i.e. initial pH, catalyst dose, hydrogen peroxide dose, initial concentration of Py and initial concentration of Qn were highly significant according to the p values (p < 0.05). The quadratic model was found to be the best fit for experimental data. The present study revealed that BBD was reliable and effective for the determination of the optimum conditions for CWPO of NHCs (Py-Qn).

• Journal of Environmental Impact Assessment
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• v.32 no.5
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• pp.353-362
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• 2023

TOC, which can measure more than 90% of organic substances, can be measured quickly and easily,replacing BOD and COD, which were indicators of organic pollutants. According to water quality pollution control standards, when measuring TOC, if the inorganic carbon ratio in the sample is over 50%, the NPOC (Non-Purgeable Organic Carbon) method should be used. If volatile organic compounds (VOCs) are present at a certain concentration, the TC-IC (subtracting inorganic carbon from total carbon) method should be used. To validate the limitations of these analytical conditions, experiments were conducted by varying the ratio of TOC to IC in purified water and measuring the concentration of TOC in test solutions. The results showed no significant difference between the TC-IC method and the NPOC method. When measuring samples with added VOC standard solutions, it was observed that the carbon loss due to purging was not significant when using the NPOC method. Therefore, it is concluded that the choice of analytical method does not lead to significant differences when VOCs are present in the sample. To account for potential variations in results based on water quality pollution control standards and regulations regarding the approval and testing of environmental measurement devices, a comparison of field sample concentration values was made using two widely used types of TOC analyzers in Korea. The results showed variations of 0.02 to 0.83 mg/L between methods depending on the manufacturer, highlighting the need for caution when selecting an instrument.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.3
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• pp.151-155
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• 2004

The bioremediation of water system contaminated with phenolic compounds having endocrine-disrupting activity, i.e. 2,4-dichlorophenol, 2,4-dichlorophenoxy acetic acid (2,4-D), and 2,4,5-trichlorophenoxy acetic acid (2,4,5-T), was investigated by using ozone oxidation and activated sludge treatment. Ozone oxidation (ozonation time: 30 min) followed by activated sludge treatment (incubation time: 5 days) was an efficient treatment method for the conversion of phenolic compounds in water into carbon dioxide and decreased the value of total organic carbon (TOC) up to about 10% of initial value. Furthermore, 2,4-D was dissolved in water containing salt, i.e. artificial seawater (ASW), and this water was used as model coastal water contaminated with phenolic compounds. The activated sludge treatment (incubation time: 5 days) could consume significantly organic acids produced from 2,4-D in the model costal water by the ozone oxidation (ozonation time: 30min) and decrease the value of TOC up to about 35% of initial value.

• Journal of Korean Society for Atmospheric Environment
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• v.32 no.6
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• pp.633-641
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• 2016

Two identical Particle Into Liquid Samplers-Total Organic Carbon (PILS-TOC) were operated to measure fine particle Water Soluble Organic Carbon (WSOC) for one week on Feb. in 2016. The dual instrument operations provided validated WSOC concentrations to have a continuous WSOC measurement during the sample analysis period. Both PILS-TOC instruments were operated downstream of an carbon denuder to remove positive adsorption artifacts associated with semi-volatile organic compounds. Comparison of WSOC showed good agreement each other. The linear regression had a coefficient of determination ($r^2$) of 0.92 and a regression slope of 1.01 for the first period. The lower collection efficiency due to lower steam temperature is discussed. In addition, the potential primary source related to WSOC based on the comparison of black carbon (BC) concentrations is explained. The results of good agreement between two PILS-TOC measurements can provide the validation of WSOC cooperations and knowledge regarding the origins of WSOC and their behaviors.

• Korean Journal of Ecology and Environment
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• v.40 no.2
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• pp.193-200
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• 2007

The objective of this study was to estimate uncertainty of online TOC analyzer in water quality monitoring system. A procedure for the estimation of measurement uncertainty of total organic compounds (TOC) based on the ISO approach is presented. It is based on a mathematical model that involves 4 input parameters (standardization, sensitivity, solute effect and representativeness). In this study, a major problem in estimating the uncertainty of online TOC analyzer was the solute effect. It was strongly depends on organic materials. So homogeneity of the sample is the most important consideration. Modified concentration and combined standard uncertainty was $4.71{\pm}0.36$ mg $L^{-1}$ by model modified in this study.

• Journal of Industrial Technology
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• v.29 no.A
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• pp.83-88
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• 2009

The removal efficiency of organic compounds and the toxicity evaluation of microorganism have been studied in dye wastewater treatment using $UV/TiO_2$ and $UV/H_2O_2$ photooxidation system. Sample waters tested in this work were raw dye wastewater and dye wastewater treated in $UV/TiO_2$ and $UV/H_2O_2$ photooxidation system respectively. Total organic carbon(TOC) removal rate was 50% in $UV/TiO_2$ process and 80% in $UV/H_2O_2$ process. It has been investigated with colony counting agar method and paper disk method whether the type of treatment process has affected the microorganism growth. In the raw wastewater, more than four types of microorganisms have survived. But, little of microorganisms were alive at TOC removal rate of 50% in $UV/TiO_2$ system. In contrast to that, two types of microorganisms were found at TOC removal rate of 80% in $UV/H_2O_2$ system.

• Particle and aerosol research
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• v.9 no.3
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• pp.187-197
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• 2013

To understand the characteristics of organic aerosol(OA) at the background atmosphere of Korea, an observation of atmospheric PM10 was conducted at a Global Atmospheric Watch(GAW) station operated by the Korean Meteorological Administration at Anmyon Island during 2010. Various organic compounds were analyzed from 26 samples by using a gas chromatography-mass spectrometer. Water soluble organic carbon(WSOC) was also analyzed by using a total organic carbon(TOC) analyzer. Among 6 classes with 68 target compounds detected, the classes of n-alkanoic and alkenoic acids ($326.67{\pm}75.40ngm^{-3}$) and dicarboxylic acids ($323.74{\pm}361.89ngm^{-3}$) were found to be major compound classes in the atmosphere of Anmyon Island. Compared to the previous results reported for 2005 spring samples at Gosan site, the concentrations of organic compounds at Anmyon Island were 3-10 times higher than Gosan site due to the difference of location and sampling period. The concentrations of organic compounds were varied with the atmospheric conditions. Significant increase of the concentrations of dicarboxylic and carboxylic acids in the smog episode indicated that secondary oxidation of organic compounds was major factor to increase OA concentration during smog episode in the Anmyon Island. It was found that the compositions of the OA measured at Anmyon Island were dependent on the air parcel trajectories.