• Asian Journal of Atmospheric Environment
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• v.11 no.2
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• pp.96-106
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• 2017

In this study, measurements of size-segregated particulate matter (PM) emitted from the combustion of rice straw, pine needles, and sesame stem were conducted in a laboratory chamber. The collected samples were used to analyze amounts of organic and elemental carbon (OC and EC), water-soluble organic carbon (WSOC), humic-like substances (HULIS), and ionic species. The light absorption properties of size-resolved water extracts were measured using ultraviolet-visible spectroscopy. A solid-phase extraction method was first used to separate the size-resolved HULIS fraction, which was then quantified by a total organic carbon analyzer. The results show that regardless of particle cut sizes, the contributions of size-resolved HULIS ($=1.94{\times}HULIS-C$) to PM size fractions ($PM_{0.32}$, $PM_{0.55}$, $PM_{1.0}$, and $PM_{1.8}$) were similar, accounting for 25.2-27.6, 15.2-22.4 and 28.2-28.7% for rice straw, pine needle, and sesame stem smoke samples, respectively. The $PM_{1.8}$ fraction revealed WSOC/OC and HULIS-C/WSOC ratios of 0.51 and 0.60, 0.44 and 0.40, and 0.50 and 0.60 for the rice straw, pine needle, and sesame stem burning emissions, respectively. Strong absorption with decreasing wavelength was found by the water extracts from size-resolved biomass burning aerosols. The absorption ${\AA}ngstr{\ddot{o}}m $ exponent values of the size-resolved water extracts fitted between 300 and 400 nm wavelengths for particle sizes of $0.32-1.0{\mu}m$ were 6.6-7.7 for the rice straw burning samples, and 7.5-8.0 for the sesame stem burning samples. The average mass absorption efficiencies of size-resolved WSOC and HULIS-C at 365 nm were 1.09 (range: 0.89-1.61) and 1.82 (range: 1.33-2.06) $m^2/g{\cdot}C$ for rice straw smoke aerosols, and 1.13 (range: 0.85-1.52) and 1.83 (range: 1.44-2.05) $m^2/g{\cdot}C$ for sesame stem smoke aerosols, respectively. The light absorption of size-resolved water extracts measured at 365 nm showed strong correlations with WSOC and HULIS-C concentrations ($R^2=0.89-0.93$), indicating significant contribution of HULIS component from biomass burning emissions to the light absorption of ambient aerosols.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.5
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• pp.727-736
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• 2006

Granular activated carbon (GAC) has been identified as a best available technology (BAT) by the United States Environmental Protection Agency (USEPA) for removal disinfection by-product (DBP) precursors, such as dissolved organic carbon (DOC) and dissolved organic nitrogen (DON). Rapid small-scale column test (RSSCT) were used to investigate four types of carbon (F400, Norit1240, Norit40S, and Aquasorb1500) for their affinity to absorb natural organic matter (NOM). DOC, $UV_{254}$, and Total dissolved nitrogen (TON) concentrations were measured in the column effluent to track GAC breakthrough. DOC and $UV_{254}$ breakthrough occurred at around 3500 bed volumes (BVs) of operation for all GACs investigated. The $UV_{254}$ breakthrough curves showed 33% to 48% at 8000 BVs, when the DOC was 48% to 65%. All GACs showed greater removal in DOC than $UV_{254}$. The NORIT1240 GAC was determined to have the highest adsorption capacity for DOC and $UV_{254}$. The removal of nitrate (NOTN) had not broken through over BVs. The initial TON breakthrough curves were started around 50%, when the DOC breakthrough was only 10 % at 500 BVs. The curves were gradually increased after 3500 BVs and approximately 69% through 81% of TON breakthrough occurred at 8000 BVs. All of the GACs were able to remove TON, in the case of this investigation the majority of the TON was present as DON. Because nitrate nitrogen was seldom removed and ammonium nitrogen ($NH_3-N$) was not detected in the effluent from RSSCTs even though raw water. The carbon usage rate of DOC was from 2 to 6 times less than that of TON. The NORIT1240 GAC demonstrated the best performance in terms of DOC removal, while the F400 GAC was best in terms of TON removal. Excitation emission matrix(EEM) analysis was used to show that GAC adsorption successfully removed most of Humic-like DOC and Fulvic-like DOCs. However, soluble microbial product(SMP)-like DOC in the absence of raw water were detected in the NORIT40S and Aquasorb1500 GAC. The authors assumed that this results is due probably to the part of GAC in the RSSCT which was converted into biological activated carbon(BAC). To compare with organics removal by GAC according to preloading, the virgin GACs had readily accessible sites that were adsorbed DOC more rapidly than preloaded GACs, but the TDN removal had not showed differences between those GACs.

• Asian Journal of Atmospheric Environment
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• v.11 no.2
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• pp.79-95
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• 2017

A number of field studies have provided evidence that biomass burning is one of the major global sources of atmospheric particles. In this study, we have collected $PM_{2.5}$ emitted from biomass burning combusted at open burning and laboratory chamber situations. The open burning experiment was conducted with the cooperation of 9 farmers in Chiba Prefecture, Japan, while the chamber experiment was designed to evaluate the characteristics of chemical components among 14 different plant species. The analyzed categories were $PM_{2.5}$ mass concentration, organic carbon (OC), elemental carbon (EC), ionic components ($Na^+$, ${NH_4}^+$, $Ca^{2+}$, $Mg^{2+}$, $K^+$, $Cl^-$, ${NO_3}^-$ and ${SO_4}^{2-}$), water-soluble organic carbon (WSOC), water-insoluble inorganic carbon (WIOC), char-EC and soot-EC. OC was the dominant chemical component, accounting for the major fraction of primary $PM_{2.5}$ derived from biomass burning, followed by EC. Ionic components contributed a small portion of $PM_{2.5}$, as well as that of $K^+$. In some cases, $K^+$ is used as biomass burning tracer; however, the observations obtained in this study suggest that $K^+$ may not always be suitable as a tracer for biomass burning emissions. Also, the results of all the samples tested indicate relatively low values of char-EC compared to soot-EC. From our results, careful consideration should be given to the usage of $K^+$ and char-EC as indicators of biomass burning. The calculated ratios of WSOC/OC and WIOC/OC were 55.7% and 44.3% on average for all samples, which showed no large difference between them. The organic materials to OC ratio, which is often used for chemical mass closure model, was roughly estimated by two independent methods, resulting in a factor of 1.7 for biomass burning emissions.

• Journal of Korean Society for Atmospheric Environment
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• v.23 no.6
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• pp.675-688
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• 2007

To characterize organic and elemental carbon (OC and EC), and water-soluble organic carbon (WSOC) contents, daily $PM_{2.5}$ measurements were performed in August 2006 (summer) and Jan $11{\sim}Feb$ 12 2007 (winter) at an urban site of Gwangju. Daily size-segregated aerosol samples were also collected for WSOC analysis. No clear seasonal variations in EC and WSOC concentrations were observed, while seasonal differences in OC concentration, and OC/EC and WSOC/EC ratios were shown. The WSOC/OC ratio showed higher value in summer (0.56) than in winter (0.40), reflecting the greater enhancement of secondary WSOC formation at the site in summer. Secondary WSOC concentrations estimated using EC tracer method were in the range $0.0{\sim}2.1\;{\mu}g/m^3$ (average $0.42\;{\mu}g/m^3$) and $0.0{\sim}1.1\;{\mu}g/m^3\;(0.24\;{\mu}g/m^3)$, respectively, accounting for $0{\sim}51.6%$ (average 16.8%) and $0{\sim}52.5%$ (average 13.1 %) of the measured WSOC concentrations in summer and winter. Sometimes higher WSOC/OC ratio in winter than that in summer could be attributed to two reasons. One is that the stable atmospheric condition often appears in winter, and the prolonged residence time would strengthen atmospheric oxidation of volatile organic compounds. The other is that decrease of ambient temperature in winter would enhance the condensation of volatile secondary WSOC on pre-existing aerosols. In summertime, atmospheric aerosols and WSOC concentrations showed bimodal size distributions, peaking at the size ranges $0.32{\sim}0.56\;{\mu}m$ (condensation mode) and $3.2{\sim}5.6\;{\mu}m$ (coarse mode), respectively. During the wintertime, atmospheric aerosols showed a bimodal character, while WSOC concentrations showed a unimodal pattern. Size distributions of atmospheric aerosols and WSOC with a peak in the size range $0.32{\sim}0.56\;{\mu}m$ were observed for most of the measurement periods. On January 17, however, atmospheric aerosols and WOSC exhibited size distributions with modal peaks in the size range $1.0{\sim}1.8\;{\mu}m$, suggesting that the aerosol particles collected on that day could be expected to be more aged, i.e, longer residence time, than the aerosols at other sampling periods.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.4
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• pp.791-799
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• 2015

This study focuses on the algae growth restraining. Many researches on a critical damage from algae growth are published, but it is hard to find how th restrain. Abnormal algae increasing is a problem, because it makes red tides, biodeterioration, etc. Therefore this study aims to decrease the damage from algae growth. Some metal ions have been used microorganism killing materials from old times. Especially, Cu ions are highly effective. Based on these uses of the metal ions, a functional mortar which restrains algae growth is developed. The mortar contains soluble glass which dissolve in water. The soluble glass was made of Cu ions and phosphates. When the soluble glass is dissolved, Cu ions are soaked out stably from the soluble glass. Culture mediums which incubate algae were made to evaluate the developed mortar specimens. Culture mediums were filled with fresh water and sea water. Algae were incubated for fourteen days in culture mediums. The evaluating methods are measuring volume of the dissolved organic carbon and the chlorophyll. Using these two measurements, the mortar specimens are judged that can restrain algae or not. According to the result, the functional mortars of culture medium filled with fresh and sea water shows similar trend. The functional mortar for restraining algae growth performs that's role well.

• Journal of Wetlands Research
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• v.14 no.4
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• pp.629-635
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• 2012

This study was conducted to evaluate the removal behaviors of DOM(dissolved organic matter) and phosphorus in eutrophic lake water by coagulation process with PAC(powdered activated carbon). It was observed that the removal characteristic of soluble matter was different from that of dissolved one, and the removal of DOM was effected by both pH and coagulant dosage. It was founded that PAC could increase the removal efficiency by an adsorption of DOM in coagulation process. A formation of soluble and colloidal matters resulted in the degradation of phosphorus removal efficiency in a chemical precipitation process. The phosphorus removal efficiency could be enhanced by an absorption of colloidal matter and dissolved complex with PAC addition. In addition, the PAC addition caused the increase of floc density in coagulation process, that led to the rise of sedimentation rate, and resulted in a significant improvement of solid-liquid separation efficiency.

• Journal of Environmental Impact Assessment
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• v.16 no.1
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• pp.69-77
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• 2007

This study has been conducted to assess blackish-water phenomena in Dam reservoir. To searching for the reason, we survey physical changes in reservoir and analyze metal and organic content in particulate materials and water. The blackish-water phenomena in lake A are occurred with turbidity increases in turnover season irregularly. It was reported on 6 Jan. 2005 weakly and the water column mixed with 35~40m depth and water temperature shows $7^{\circ}C$. The turbidity of AD and AM site increased up to 20NTU. Especially, AN site shows 27NTU, such a result makes that Dam manager conclude it to blackish-water phenomena. The results of sequential extraction analysis show that over 80% of Al, Cr and Fe is existed in residual form in sediment. On the other hand, the most part of Mn shows exchangeable and carbonates form, which have a good possibility of release to water column. Mn contents in pore waters of the sediment samples are also found to be ~4 times higher than Fe contents. The metal contents in pore water of different dam sites are in order of AN (Fe: 9.98, Mn: 40.6) > AD(8.33, 37.5) > DD(1.91, 2.55). According to the results of extracted organic materials from sediment, humic substances is occupied with over 85% in total organic carbon including 23~45% of humic acid (HA) and 0.9~8.5% of fulvic acid (FA). However, HA content in pore water is not detectable while FA contents, acid-soluble humic fractions is higher than that of sediment(10~15%). which indicating that FA is a main humic components affecting water color. The color unit per DOC of FA in pore waters of different dam sites are found to be higher in lake A than lake D. From the results, it could be suggested that blackish-water phenomena of lake A are mainly arise from higher concentration of Mn and water soluble organic fractions (e.g., FA) released from sediments as well as the strength of turnover in Dam reservoir.

• Journal of Korean Society of Water and Wastewater
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• v.32 no.2
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• pp.145-152
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• 2018

This study is focused on manganese (Mn(II)) removal by ozonation in surface water. Instant ozone demand for the water was 0.5 mg/L in the study. When 0.5 mg/L of Mn(II) is existed in water, the optimum ozone concentration was 1.25 mg/L with reaction time 10 minutes to meet the drinking water regulation. The ozone concentration to meet the drinking water regulation was much higher than the stoichiometric concentration. The reaction of soluble manganese removal was so fast that the reaction time does not affect the removal dramatically. When Mn(II) is existed with Fe, the removal of Mn(II) was not affected by Fe ion. However As(V) is existed as co-ion the removal of Mn(II) was decreased by 10%. Adding ozone to surface water has limited effect to remove dissolved organic matter. When ozone is used as oxidant to remove Mn(II) in the water, the existing co-ion should be evaluated to determine optimum concentration.

• Journal of Korean Society of Water and Wastewater
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• v.12 no.3
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• pp.21-29
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• 1998

The ozone/GAC process, sometimes termed BAC(Biological Activated Carbon) appeared to be effective for the removal of soluble organic matters in the drinking water Chabrol is a simple model for the simulation like as the variation of HPC and BDOC in the BAC tower. This study were carried out to calibrate of HPC and BDOC and to evaluate $H_1$ and $H_2$ of ozone-treated water with Chabrol model. BDOC values of the ozone-treated water and BAC effluent are analyzed using method of Levi and Joret. As the ozone-treated water and BAC Effluent are incubated, the HPC are increased up to 0.24 mgC/l and 0.09 mgC/l respectively. $H_1$ and $H_2$ of the ozone-treated water is 0.3 mgC/l and 0.349 mgC/l respectively and Chabrol model for BAC tower can be calibrated.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1625-1628
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• 2007

Dispersion of arc-discharged single-walled carbon nanotubes (SWNTs) has been accomplished by a water soluble polymer wrapping functionalization at room temperature. The treated SWNTs were redispersed in both aqueous and many organic solvents and the solutions were found to be stable.