• Membrane and Water Treatment
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• 제9권1호
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• pp.9-15
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• 2018

Coagulation process using aluminum sulfate ($Al_2(SO_4)_3$) and ferric chloride ($FeCl_3$) was employed as a treatment method for decolorization of a synthetic textile wastewater containing red dye in this paper. Factors such as initial pH, coagulant dosage, initial concentration, conductivity and mixing conditions that influence color removal efficiency were experimentally tested. It was found that $Al_2(SO_4)_3$ is more efficient than $FeCl_3$ as coagulant. When $40mgL^{-1}$ aluminum sulfate was used, results showed that color induced by the red dye was efficiently removed (> 90 %) and was obtained in a large range of initial pH from 4 to 8 with, and for a dye concentration lower than $235mg\;L^{-1}$. After addition of the coagulant, the medium had to be mixed for 30 min at 60 rpm, then allowed to settle for 40 min. The effects of water conductivity in the range $0.035-2.42mS\;cm^{-1}$ and dye concentration up to $380mg\;L^{-1}$ were also followed and discussed.

• 한국의류학회지
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• 제20권3호
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• pp.550-559
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• 1996

The Effect of protease (subtilisin Carlsberg) on the removal of hemoglobin as protein soil was studied. The hydrolysis characteristics of subtilisin Carlsberg was examined by electrophoretic techniques. The fragmentation patterns of hemoglobin were analyzed by SDS-PAGE. The hydrolysis efficiency was evaluated by analysis of protein bands shown on gels before and after hydrolysis by using densitometer. 1. The hydrolysis of hemoglobin by subtilisin Carlsberg was increased markedly with the increase of the enzyme concentration. 2. The hydrolysis of hemoglobin by subtilisin Carlsberg was effectively increased in proportion to increasing of the hemoglobin concentration up to a certain point, but it began to decrease above the point. 3. The hydrolysis of hemoglobin by subtilisin Carlsberg followed the first order kinetics, yielding a rate constant of $4.05\time10^{-4}S^{-1}s$. 4. The hydrolysis of hemoglobin by subtilisin Carlsberg was highest at $50^{\circ}C$ and was decreased markedly at $80^{\circ}C$. 5. The hydrolysis of hemoglobin was comparatively low at pH 7.0~8.0, and highest at pH 11.0.

• 대한토목학회논문집
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• 제41권4호
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• pp.357-364
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• 2021

본 연구에서는 서로 다른 종류의 TiO₂ 혼입이 시멘트 페이스트의 수화특성 및 질소산화물 제거성능에 미치는 영향에 대해 조사하였다. 상용 제품인 P-25와 NP-400, 폐수 슬러지에서 제조된 GST, 총 세 종류의 TiO₂를 시멘트 무게대비 0, 5, 10, 20 % 첨가하여 시멘트 페이스트의 수화특성 및 질소산화물 제거성능을 분석하였다. 미소수화열 측정결과 TiO₂의 혼입은 시멘트 페이스트의 초기 수화반응에 큰 영향을 미치는 것이 확인되었으며, P-25, NP-400, GST 순으로 더 높은 누적 발열량을 나타내었다. 이로 인해 Rietveld 분석결과 TiO₂ 혼입 샘플에서 더 많은 C-S-H의 생성량이 관찰되었으며, 이는 TiO₂ 혼입 시멘트 페이스트의 28일 압축강도 증가에 영향을 미친 것으로 판단된다. SEM/EDS 분석결과 P-25, GST, NP-400 순으로 페이스트 샘플 표면에 더 많은 Ti 원소의 함량이 관찰되었지만, NO_x 제거 성능은 P-25, NP-400, GST 순으로 우수한 것으로 확인되었다.

• 한국수소및신에너지학회논문집
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• 제27권4호
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• pp.412-420
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• 2016

Effect of $H_2S$ on reactivity of oxygen carrier was measured and discussed using fluidized bed reactor and SDN70 oxygen carrier. We could get 100% of fuel conversion and $CO_2$ selectivity even though $H_2S$ containing simulated syngas was used as fuel for reduction. Absorbed sulfur was released during oxidation and $N_2$ purge step after oxidation as $SO_2$ form. We could get 100% of fuel conversion and $CO_2$ selectivity during cyclic reduction-oxidation tests up to 10th cycle. However, only 6~7% of sulfur can be removed during oxidation and $N_2$ purge step and 93~94% of sulfur was accumulated in the oxygen carrier. Therefore we could conclude that total removal of sulfur was not possible. $SO_2$ emission during oxidation decreased as the number of cycle increased. Therefore we could expect that the reactivity of oxygen carrier will be decreased with time.

• 웰빙융합연구
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• 제5권2호
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• pp.21-27
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• 2022

Purpose: This study is about photocatalytic technology and plasma oxidation-reduction technology. To the main cause of exposure to odor pollution, two deodorization techniques were applied to develop a module with higher removal efficiency and ozone reduction effect. Research design, data and methodology: A composite module was constructed by arranging two types of dry deodorization equipment (catalyst, adsorbent) in one module. This method was designed to increase the responsiveness to the components of complex odors and the environment. standard, unity, two types of oxidizing photo-catalyst technology and plasma dry deodorization device installed in one module to increase the potential by reduction to 76% of ozone, 100%, and 82%. Results: The complex odor disposal efficiency was 92%. Ammonia was processed with 50% hydrogen sulfide and 100% hydrogen sulfide, and ozone was 0.01ppm, achieving a target value of 0.07ppm or less. The combined odor showed a disposal efficiency of 93%, ammonia was 82% and hydrogen sulfide was 100% processed, and ozone achieved a target value of 0.07 ppm or less. Conclusions: Ozone removal efficiency was 76% by increasing Oxidation-Reduction Reaction(ORR). The H2S removal efficiency of the deodorizer was higher than that of the biofilter system currently used in sewage disposal plants.

• 한국환경과학회지
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• 제21권4호
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• pp.479-488
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• 2012

A Dielectric barrier discharge (DBD) plasma is shown in the present investigation to be effective of phenol degradation in the aqueous solutions in batch reactor with continuous air bubbling. Removal of phenol and effects of various parameters on the removal efficiency in the aqueous solution with high-voltage streamer discharge plasma are studied. The effect of 1st voltage (80 ~ 220 V), air flow rate (3 ~ 7 L/min), pH (3 ~ 11), electric conductivity of solution (4.16 ${\mu}S$/cm, deionized water) ~ 16.57 mS/cm (addition of NaCl 10 g/L) and initial phenol concentration (2.5 ~ 20.0 mg/L) were investigated. The observed results showed that phenol degradation was higher in the basic solution than that of the acidic. The optimum values on the 1st voltage and air flow rate for phenol degradation were 140 V and 6 L/min, respectively. It was considered that absorbance variation of $UV_{254}$ of phenol solution can be use as an indirect indicator of change of the non-biodegradable organic compounds within the treated phenol solution. Electric conductivity was not influenced the phenol degradation. To obtain the removal efficiency of phenol and COD of phenol over 97 % (initial phenol concentration, 10.0 mg/L), 80 min and 120 min were need, respectively. Phenol and COD degradation showed a pseudo-first order kinetics.

• Carbon letters
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• 제8권3호
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• pp.191-198
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• 2007

Recent studies have revealed the poisonous nature of aluminum(III) species to aquatic and terrestrial organisms. Therefore, this investigation aims to develop batch adsorption experiments in the laboratory, aiming to the removal of aluminum(III) from aqueous solutions onto powdered activated carbon (PAC). The latter (which is an effective and inexpensive sorbent) was prepared from olive stones generated as plant wastes and modified with an aqueous modifying oxidizing agent, viz. $HNO_3$. The main parameters (i.e. initial solution pH, sorbent and $Al^{3+}$ ions concentrations, stirring times and temperature) influencing the sorption process were examined. The results obtained revealed that the sorption of $Al^{3+}$ ions onto PAC is endothermic in nature and follows first-order kinetics. The adsorption data were well described by the Langmuir, Freundlich and Dubinin-Radushkevich (D-R) adsorption models over the concentration range studied. Under the optimum experimental conditions employed, the removal of ca. 100% $Al^{3+}$ ions in the concentration range $1.35-2.75\;mg{\cdot}l^{-1}$ was attained. Moreover, the procedure was successfully applied to the recovery of aluminum spiked to some environmental water samples with an RSD (%), does not exceed 1.22%.

• 원예과학기술지
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• 제33권1호
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• pp.106-113
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• 2015

Effects of mineral salts (N, P, K, $Ca^{2+}$, $Mg^{2+}$, and $Fe^{3+}$) on the shoot growth and metabolite production of tea tree were studied using in vitro culture techniques. Among mineral s alts, ${H_2PO_4}^-$ was the most important for enhanced growth rate of tea tree, while $Mg^{2+}$ and $Ca^{2+}$ did not affect plant growth. Removal of ${NH_4}^+$ and $NO_3$ from the culture medium enhanced shoot multiplication compared to other treatments. Metabolite production was variable depending on mineral types and concentration. Removal of $Ca^{2+}$ decreased the production of caffeine; however, other treatments did not influence its production. $Ca^{2+}$, ${NH_4}^+$ and $Fe^{3+}$ were important factors for catechin production in tea tree. These results can be used as the basis for development of technical soil controls suitable for tea tree cultivation in the future.

• 한국지하수토양환경학회지:지하수토양환경
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• 제12권2호
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• pp.27-36
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• 2007

기존의 연구를 통해 Fenton's reagent(FR)를 이용하여 MTBE의 제거가 가능하며, 그러나 중성 pH영역에서는 철이온이 수산화물로 침전되어 반응성이 낮아지므로 FR만을 이용한 처리는 높은 수소이온 농도조건(pH $3{\sim}4$)이라는 제약으로 인해 직접적인 토양 및 지하수의 MTBE 오염처리에 있어 여러 가지 어려움이 있다. 이에 본 연구에서는 효과적인 처리를 위하여 NTA, oxalate, acetate 등의 chelating agent가 철이온과 반응하여 생성된 착화합물을 이용하는 modified Fenton reaction을 도입하여 중성 pH영역에서도 철이온이 안정화되어 높은 분해효율을 나타낼 수 있도록 하였다. MTBE의 분해경향은 chelating agent의 종류와 농도, 철이온 농도 그리고 pH 변화에 따라 크게 영향을 받는 것으로 나타났다. 가장 적합한 착화합물을 선택하기 위하여 총 6개의 chelating agent(citrate, oxalate, succinate, acetate, NTA, EDTA)를 실험한 결과, 처리효율과 chelating agent의 생분해도, 독성 등을 고려하여 최종 3가지 종(oxalate, acetate, NTA)이 선정되어 이후의 실험에서는 위의 3종만을 chelating agent로 이용하였다. 동일한 실험조건($H_2O_2$ : 5%, chelating agent : 6 mM, $Fe^{3+}$ : 2 mM, pH 7)하에서의 적용성 평가한 결과, Fe-NTA가 반응시작 30분만에 99.9%의 가장 높은 제거효율을 나타내었다. Oxalate의 경우, NTA보다는 그 분해효율이 낮으나 다른 chelating agent보다 상대적으로 높은 효율(24시간 후 최대효율 : 91.3%)을 보여주며, acetate를 이용한 경우도 본 실험에서 좋은 결과(24시간 후 최대효율 : 75.8%)를 나타내었다. 또한, 적정 철이온의 농도는 oxalate가 chelating agent로 이용되면 철이온 농도가 3 mM일때 가장 큰 분해효율을 보이며, acetate의 경우는 5 mM까지 농도가 증가함에 따라 그 효율도 조금씩 증가하는 것으로 나타났다. 이와같이 MTBE의 in-situ remediation을 위한 modified Fenton 공정은 철이온을 중성 pH영역에서 안정화시켜 실제 토양에 적용하였을 때, 높은 분해효율을 얻을 수 있으며, 경제적인 자체 생분해도가 높은 저분자 유기산을 이용하였으므로 생물학적 처리와 연계를 가능하게 해주는 장점을 나타낸다. 또한 토양 내 존재하는 철광석을 촉매로 이용할 경우, 주입되는 철이온 없이도 $H_2O_2$에서의 hydroxyl radical 생성을 증가 시킬 수 있으므로 보다 경제적이고 친환경적인 처리기법을 도출해 낼 수 있다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.177-180
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• 2005

Three dimensional shaded images are standard visualization method for CAD models on the computer screen. Therefore, much of the effort in the visualization of CAD models has been focused on how conveniently and realistically CAD models can be displayed on the screen. However, shaded 3D CAD data images captured from the screen may not be suitable for some application areas. Technical document, either in the paper or electronic form, can more clearly describe the shape and annotate parts of the model by using projected 2D line drawing format viewed from a user defined view direction. This paper describes an efficient method for generating such a 2D line drawing data in the vector format. The algorithm is composed of silhouette line detection, hidden line removal and cleaning processes.