• Environmental Engineering Research
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• v.20 no.4
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• pp.342-346
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• 2015

Haloacetonitriles (HANs) are nitrogenous disinfection by-products (DBPs) that have been reported to have a higher toxicity than the other groups of DBPs. The adsorption process is mostly used to remove HANs in aqueous solutions. Functionalized composite materials tend to be effective adsorbents due to their hydrophobicity and specific adsorptive mechanism. In this study, the removal of dichloroacetonitrile (DCAN) from tap water by adsorption on thiol-functionalized mesoporous composites made from natural rubber (NR) and hexagonal mesoporous silica (HMS-SH) was investigated. Fourier-transform infrared spectroscopy (FTIR) results revealed that the thiol group of NR/HMS was covered with NR molecules. X-ray diffraction (XRD) analysis indicated an expansion of the hexagonal unit cell. Adsorption kinetic and isotherm models were used to determine the adsorption mechanisms and the experiments revealed that NR/HMS-SH had a higher DCAN adsorption capacity than powered activated carbon (PAC). NR/HMS-SH adsorption reached equilibrium after 12 hours and its adsorption kinetics fit well with a pseudo-second-order model. A linear model was found to fit well with the DCAN adsorption isotherm at a low concentration level.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.7 no.3
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• pp.61-69
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• 1987

In water treatment, prechlorination is often carried out to solve the troubles caused by Algae, but produces by-products that are known to be harmfull to human health. In this study, chlorine and chlorine dioxide used for algae removal process were compared in producing trihalomethanes and haloacetonitriles to study the possibilities in using chlorine dioxide as a alternative for chlorine. The raw water used for the study had 10,790 algae cells per one milliliter and Ankistrodesmus sp. were the most common.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.2
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• pp.224-227
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• 2005

먹는물에서 염소소독 부산물로서 휘발성유기화합물인 디클로로아세트니트닐(DCAN), 트리클로로아세트니트릴(TCAN), 디브로모아세트니트릴(DBAN), 브로모클로로아세트니트릴(BCAN)의 4종류의 물질을 대상으로 탈기법(air stripping) 및 탈기법(air stripping)과 자외선에너지($8\;W{\times}6$)를 이용하여 분해시험을 행하였다. 물질들의 확인은 가스크로마토 그래프, 이온크로마토그래프 그리고 자외선분광광도계를 사용하였다. TCAN은 탈기법 이용한 방법에서 제거가 되었으며, DBAN과 BCAN에서는 자외선에너지에 의해 분해가 되었다.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.5
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• pp.547-554
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• 2013

Chlorine has strong oxidizing power, also it is many advantages over other disinfectants such as the residual characteristic and economic feasibility. However, chlorine also has disadvantages such as creating disinfection by-products of chlorine as THMs. In particular, the most deadly disadvantage of chlorine is that it is extremely poisonous toxins about all alive lives. Disinfection with electrolysis water can be a very useful way Because you do not have to worry about chlorine's dangerous. In this study, we evaluated the potential as a disinfectant, across the evaluating disinfection effect and generating characteristic of by-products. The electrolyzed water could be obtained removal efficiencies of over 99.9 % the coliform by operating condition such as residence time, current density (voltage), the electrode gap. The residual chlorine be generated 10,000 mg/L in current density $1.0A/dm^2$ and residence time of 10 minutes. The residual chlorine concentration was possible to maintain a stable. The by-products generated by high concentration residual chlorine in the reactor such as trihalomethanes, haloaceticacid, chloralhydrate, haloacetonitrile were detected in less than a water quality standards. At the concentration of less than residual chlorine of 1 ppm, the chlorine disinfection by-products be generated most below the detection limit.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.9
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• pp.505-510
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• 2015

This study investigated formation potential of 16 disinfection byproducts (DBPs) (e.g., g trihalomethanes, haloacetic acids, haloacetonitriles, chloral hydrate, etc.) upon chlorination of raw water at various pH, water temperatures, and chlorine doses. We also compared the DBP formation potential (DBPFP) of raw and filtered waters. Most of DBPs were formed higher at neutral pH, but dichloroacetic acid, chloroform, and bromodichloromethane were formed higher over pH 7. As water temperature increased, concentrations of chloral hydrate, haloacetic acids, and haloacetonitriles linearly increased while that of trihalomethanes exponentially increased. Formation of chloral hydrate, trihalomethanes, and trihaloacetonitriles significantly increased up to 2.0 mg/L $Cl_2$ of chlorine addition, then gradually increased at 2.0~5.6 mg/L $Cl_2$. Filtered water formed less DBPs than raw water in most DBPs except for trihalomethanes.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.5
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• pp.332-340
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• 2009

This study was conducted to analyze and determine formation potentials for chlorination disinfection by-products (DBPs) from twenty amino acid compounds with or without $Br^-$. Two of twenty amino acid compound were tryptophan and tyrosine that were relatively shown high for formation of trihalomethanes (THMs)/dissolved organic carbon (DOC) whether or not $Br^-$ presented. Other 18 compounds were shown low for formation of THMs/DOC whether or not $Br^-$ presented. Five amino acid compounds that were tryptophan, tyrosine, asparagine, aspartic acid and histidine were shown high for formation of haloacetic acids (HAAs)/DOC whether or not $Br^-$ presented. Although formation of dichloroacetic acid (DCAA) was dominated in asparagine, aspartic acid and histidine, trichloroacetic acid (TCAA) was dominated in tryptophan and tryptophan. The formation of haloacetnitriles (HANs)/DOC whether or not $Br^-$ presented was high in Aspartic acid, histidine, asparagine, tyrosine and tryptophan. Specially, aspartic acid was detected 660.2 ${\mu}$g/mg (HAN/DOC). Although the formation of chloralhydrate (CH)/DOC was shown high in asparagine, aspartic acid, histidine, methionine, tryptophan and tyrosine, the formation of Chloropicrin (CP)/DOC was low (1 ${\mu}$g/mg) in twenty amino acid compounds. The formations of THM, HAA and HAN were also investigated in functional groups of amino acids. The highest formation of THM was shown in amino acids compounds (tryptophan and tyrosine) with an aromatic functional group. Highest, second-highest, third-highest and fourth-highest functional groups for formation of HAA were aromatic, neutral, acidic and basic respectively. In order of increasing functional groups for formation of HAN were acidic, basic, neutral and aromatic.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.5
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• pp.523-530
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• 2010

This study was conducted to analyze and determine formation potentials for chlorination disinfection by-products (DBPs) from 14 synthetic nitrogen compounds with or without $Br^-$. 5 of 14 compounds were 3-aminobenzoic acid, 2-aminophenol, aniline, anthranilic acid and 4-nitroaniline that were relatively shown high for formation of THMs/DOC whether or not $Br^-$ presented. 6 compounds that were p-nitrophenol, 3-aminobenzoic acid, 2-aminophenol, aniline, anthranilic acid and 4-nitroaniline were shown high for formation of haloacetic acids (HAAs)/DOC whether or not $Br^-$ presented. Trichloroacetic acid (TCAA) was dominated in 6 compounds. The formation of haloacetonitriles (HANs)/DOC whether or not $Br^-$ presented was high in 3-aminobenzoic acid, 2-aminophenol, aniline and anthranilic acid. Specially, aniline was detected 14.6∼16.1 ${\mu}g/mg$. The formation of chloral hydrate (CH)/DOC and chloropicrin (CP)/DOC were shown high in 3-aminobenzoic acid and 2-aminophenol in 14 compounds. 6 compounds (3-aminobenzoic acid, 2-aminophenol, aniline, anthranilic acid, 4-nitroaniline, p-nitrophenol) and a commercial humic acid were tested for the formation of DBPs/DOC whether or not $Br^-$ presented. When $Br^-$ was added, the DBPs/DOC was higher for the order of aniline> anthranilic acid> 3-aminobenzoic acid> 4-nitroaniline> humic acid> p-nitrophenol> 2-aminophenol. And when $Br^-$ was not added, the DBPs/DOC was higher for the order of anthranilic acid> aniline> p-nitrophenol> humic acid> 4-nitroaniline> 3-aminobenzoic acid> 2-aminophenol.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.2
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• pp.184-191
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• 2007

Coal-, coconut- and wood-based activated carbons and anthracite were tested for an adsorption and biodegradation performances of nitrogenous chlorinated by-products such as chloropicrin, DCAN, DBAN and TCAN. In early stage of operations, an adsorption performance was a main mechanism for removal of nitrogenous chlorinated by-products, however as increasing populations of attached bacteria, the bacteria played a major role in removing nitrogenous chlorinated by-products in the activated carbon and anthracite biofilter. It was also investigated that the compounds were readily subjected to biodegrade. Whilst the coal- and coconut-based activated carbons were found most effective in adsorption of the compounds, the anthracite was worst in adsorption of the compounds. Highest populations and activity of attached bacteria were shown in the coal-based activated carbon. The populations and activity of attached bacteria decreased in the order: coconut-based activated carbon > wood-based activated carbon > anthracite. The attached bacteria were inhibited for removal of the compounds at temperatures below $10^{\circ}C$. The attached bacteria were more active at higher water temperatures$(20^{\circ}C\;<)$ but less active at love. water temperature$(10^{\circ}C\;>)$. The removal efficiencies of the compounds obtained using coal-, coconut- and wood-based activated carbons and anthracite were directly related to the water temperatures. In particular, water temperature was the most important factor for removal of the compounds in the anthracite biofilter because the removal of the compounds depended mainly on biodegradation. Therefore, the main removal mechanism of the compounds the main mechanism on the removal of the compounds using activated carbon was both adsorption and biodegradation by the attached bacteria. The observation suggests that using coal-based activated carbon is the best for removal of nitrogenous chlorinated by-products in the water treatment.