• 펄프종이기술
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• 제47권4호
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• pp.109-114
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• 2015

In this study, the effects of chlorine dioxide (D) bleaching conditions on the delignification of hemp bast fiber were elucidated. Chlorine dioxide bleaching was carried out through three stages (DED) and five stages (DEDED), respectively. Applied amounts of chlorine dioxide at $D_1$ and $D_2$ stages were varied to find the optimum bleaching condition. It was found that the optical properties of its handsheet as well as the delignification of hemp bast fiber increased as the concentration of chlorine dioxide at $D_1$ stage increased. It was also notable that the bleachability of the DEDED bleaching stages was slightly more effective than that of the DED bleaching stages. The burst index of the handsheets made with bleached hemp bast fiber was higher than that of the unbleached samples, but the burst index of these samples decreased as their delignification increased. These results indicated that the higher concentration of chlorine dioxide at $D_1$ stage was major factor to improve the bleaching efficiency of hemp bast fiber.

• 멤브레인
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• 제15권4호
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• pp.320-329
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• 2005

본 연구에서는 polyamide계 방향족 역삼투막이 염소 라디칼에 의해 polyamide 결합이 분해되어 염배제율이 급격히 감소되는 반면 수투과도는 증가되는 것을 확인하였다 이러한 polyamide 역삼투막의 염소에 대한 저항성을 향상시키기 위해서 불소기 함유 실란커플링제(fluorine-containing silane coupling agent, FSCA)를 이용하여 역삼투막 표면 개질 후 막에 대한 표면 특성 및 내염소성 변화를 관찰하였다. 그 결과 FSCA의 농도가 증가될수록 막 표면이 dense하게 도포되었으며, 원소분석을 통해 FSCA가 부착되어 있음을 확인하였다. 또한 개질한 막 표면 조도는 감소되고 표면의 소수성이 증가됨을 접촉각의 증가로 확인 할 수 있었다. 이 결과를 종합하여 볼 때, 역삼투막을 FSCA로 표면개질 함으로써 개질막의 염소에 대한 저항성을 향상시킬 수 있었다.

• 펄프종이기술
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• 제30권1호
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• pp.44-58
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• 1998

This study was carried out to bleach the Oakwood kraft pulp without the elemental chlorine using the xylanase or wastewater(We : wastewater enzymes) effluented from the submerged biofilter reactor containing the fungi, Phanerorhaete sordida YK-624. So in this research, the proper treatment conditions (pH, temperature, dosage and time) were investigated respectively. And after the various kinds of multistage bleaching of pulps, the properties of pulps were tested. From the experimental results, we can conclude as follows. In the treatments of Oakwood kraft pulps with xylanase, the proper pH, temperature, enzyme dosage and time were 8.0, $35^{\circ}C$ , 400 EXU/kg and 1 hr. respectively. And in the case of treatment with a wastewater(We) effluented from the submerged biofilter reactor, the proper pH, temperature and time were 5.5, $37^{\circ}C$ and 2 hr. respectively. On the other hand, Oakwood kraft pulps were bleached by the method of a multistage bleaching using xylanase or We instead of elemental chlorine Consequently the strengthes and brightnesses of pulps bleached by the method mentioned above were lower than those of pulp bleached by the conventional method using the elemental chlorine. But it is possible to improve the brightnesses through the increase of chlorine dioxide dosage or use of hydrogen peroxide in the final bleaching stage.

• Bulletin of the Korean Chemical Society
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• 제30권3호
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• pp.595-598
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• 2009

The authors describe an analytical method to determine total chlorine in a sanitizer liquid, incorporating a lab-made He-rf-plasma within a PDMS polymer microchip. Helium was used instead of Ar to produce a plasma to achieve efficient Cl excitation. A quartz tube 1 mm i.d. was embedded in the central channel of the polymer microchip to protect it from damage. Rotational temperature of the He-microchip plasma was in the range 1350-3600 K, as estimated from the spectrum of the OH radical. Chlorine was generated in a volatilization reaction vessel containing potassium permanganate in combination of sulfuric acid and then introduced into the polymer microchip plasma (PMP). Atomic emission lines of Cl at 438.2 nm and 837.7 nm were used for analysis; no emission was observed for Ar plasma. The achieved limit of detection was 0.81 ${\mu}g\;mL^{-1}$ (rf powers of 30-70 W), which was sensitive enough to analyze sanitizers that typically contained 100-200 ${\mu}g\;mL^{-1}$ of free chlorine in chlorinated water. This study demonstrates the usefulness of the devised PMP system in the food sciences and related industries.

• 펄프종이기술
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• 제30권3호
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• pp.84-96
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• 1998

This study was carried out to bleach the Pinewood kraft pulp without the elemental chlorine using the xylanase or wastewater(We:wastewater enzymes) effluented from the submerged biofilter reactor containing the fungi, Phanerochaete sordida YK-624. So in this research, the proper treatment conditions(pH, temperature, dosage and time) were investigated respectively. And after the various kinds of multistage bleaching of pulps, the properties of pulps were tested. From the experimental results, we can conclude as follows. In the treatments of Pinewood kraft pulps with xylanase, the proper pH, temperature, enzyme dosage and time were 8.0, $35^{\circ}C, 400EXU/kg and 3 hr. respectively. And in the case of treatment with a wastewater(We) effluented from the submerged biofilter reactor, the proper pH, temperature and time were 5.0, $37^{\circ}C and 3 hr. respectively. On the other hand, Pinewood kraft pulps were bleached by the method of a multistage bleaching using xylanase or We instead of elemental chlorine. Consequently, the strengthes and brightnesses of pulps bleached by the method mentioned above were lower than those of pulp bleached by the conventional method using the elemental chlorine. But it is possible to improve the brightnesses through the increase of chlorine dioxide dosage or use of hydrogen peroxide in the final bleaching stage.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.47-47
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• 2010

Discharge under the water is very hard and demand considerable high voltage. But specially improved electrode can generate plasma discharge to salty water with relatively low voltage. A round shape ceramic electrode having many pinholes combined with metallic one can generate plasma. 400 volt, 10 kHz and 3 micro second pulse width were applied to repeatedly running synthetic seawater with 10 L/m velocity, containing cultivated E. coli and Bacillus. As a result, 18, 94, 99.97, 100, 100 % disinfection rates to E. coli and 17.1, 17.1, 82.9, 99.4, 99.9 % disinfection rates to Bacillus subtilis were achieved to 1, 2, 3, 4, 5 times repetitive treatment respectively. In the plasma condition, the ions and electrons are separated and new kinds of components are re-synthesized by the intensive movement of the components. Especially chlorine ions are separated and recombined to residual free chlorine like HOCl, $OCl^-$. The residual free chlorine concentrations of discharged water were 0.25, 0.88, 1.39, 1.59, 1.66 mg $Cl_2$/L after 5 times treatment respectively. Another unconfirmed radical and oxidants for example, OH, $H_2O_2$, and $O_3$ can have an effect on microorganism of course.

• 한국환경보건학회지
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• 제7권1호
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• pp.33-41
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• 1981

This study was carried out to investigate Water Temperature, Residual Chlorine, Coliform Groups, and the Standard Plate Counts of Water Supply Areas provided by 7 Water Purification Plant (W.P.P) in Seoul from September 20, 1979 through October 20, 1979. The results were summarized below: 1) The mean water temperature of the 63 Water Samples was 19.8$\circ$C, the mean pH 7.18, and the mean residual chlorine concentration 0.52 ppm by each Water Supply Areas. There is no statistically significant differences between the WPP Areas, but there is significant differences between water supply areas. 2) 30(47.6%) out of the 63 Water Samples were Standard Plate Counts free and 33 Samples (52.4%) were contaminated by Standard Plate Counts. 30 (47.6%) out of 33 samples showed the existence of Standard Plate Counts less than 15 and the other 3 samples 15-30. 3) 2 (3.2%) out of the 63 Samples had the coliform. Those 2 Samples had 2 and 6 coliform group counts per 50ml respectively both of them were 0.1ppm in residual chlorine. 4) There is correlation among Water Temperature, pH, Residual Chlorine, Standard Plate Counts, and Coliform Groups. The Coefficient of Correlation(r) between Water Temperature & Residual Chlorine was 0.147, 0.240 between Water Temperature & Standard plate Counts and 0.215 between pH & Standard Plate Counts. These correlations are statistically no significant, But the correlation of coefficient between pH & Residual Chlorine was -0.291 which is showed significant correlation at p<0.05. The coefficient of correlation between Residual Chlorine & Standard Plate Counts was -0.441 which is showed Negative Correlation Statistically Significant difference at p<0.01.

• 자원리싸이클링
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• 제30권5호
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• pp.10-16
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• 2021

본 연구에서는 클링커 및 시멘트의 염소 함량에 따른 특성 변화를 분석하기 위해, 혼합원료 제조 시 CaCl₂를 첨가하여 클링커를 제조하였다. 이때 클링커 모듈러스는 LSF(Lime Saturation Factor) 92, SM(Silica Modulus) 2.5 및 IM(Iron Modulus) 1.5로 고정하였다. 또한 염소 함유 클링커를 사용하여 시멘트를 제조한 후 물리적 특성도 시험하였다. 염소 함량 증가에 따라 클링커의 free-CaO가 감소하였으며, 특히 염소 함량 0ppm 대비 2000ppm 조건에서 약 40% 감소하였다. 또한 chlormayenite 생성량도 증가하여, 2000ppm 클링커에서 최대치인 3.4%가 존재하였다. Alite와 belite 생성량도 소폭 증가하였다. 모르타르의 3일 및 7일 압축강도는 염소함량 증가에 따라 상승하였으며, 이는 염소 성분에 의한 시멘트 수화촉진 영향으로 추정되었다. 특히 1000ppm 모르타르의 압축강도는 0ppm 모르타르 대비 약 20%가 상승하는 결과가 도출되기도 하였다.

• 환경위생공학
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• 제14권1호
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• pp.11-16
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• 1999

This study was performed to investigate THMs formation by chloramination as a secondary disinfection in drinking water distribution system. As the $Cl_2/NH_3-N$ ratio increased from 1:1 to 4:1, the THMs concentration had actually no change in the breakpoint curve of pH 6, 7. At pH 8, THMs level was not augmented at between 1:1 and 5:1. In the $Cl_2/NH_3-N$ ratio of more than 5:1 and 6:1 respectively, THMs level was raised. Only the chloroform of THMs was insignificantly detected by both preformed chloramine and preammoniation applications, which was probably attributed to the stoichiometrically unstable equilibrium in the preparation of chloramine, whereas $CHCl_3$, $CHCl_2Br$ and $CHClBr_2$ of THMs were found in the application of free chlorine. However it turned out that the THMs levels by chloramine was incomparably inferior to that of free chlorine.

• 한국환경보건학회지
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• 제30권1호
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• pp.59-64
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• 2004

This study was carried out to investigate influencing factors of bisphenol A(BPA) removal characteristic in conventional water treatment systems to be connected with coagulation, sedimentation, filtration and disinfection. The result are summarized as follows; In BPA removal, optimal doses of PAC, alum, ferric chloride were 7.5 mg Al/L, 10.0 mg AI/L, 15.0 mg Fek. PAC was most effective coagulant to remove BPA. In coagulation process, BPA removal efficiency were increased about 2％ by adjusting pH of raw water as 6. At temperature rise 1$0^{\circ}C$, BPA removal efficiency were increased 0.94％. but BPA removal efficiency in sand filtration process were under 1 ％ie, so that BPA was almost not removed. At free chlorine dose 1, 2 mg/L, the reaction rate constant k in the BPA removal have been calculated to be 0.397, 0.953 min$^{-1}$ . At free chlorine dose 1, 2 mg/1-, degradation reaction of BPA was completed during 10 min and BFA removal efficiencies were 97.66, 99.99％ at this time.