• Advances in nano research
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• 제8권1호
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• pp.1-11
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• 2020

In order to develop a new adsorbent for removal of formaldehyde from aqueous solution, surface modification of TiO₂ nanoparticles was performed with 2,4-Dinitrophenylhydrazine (DNPH) that have a strong affinity to the formaldehyde. Sodium dodecyl sulfate (SDS) surfactant was used to improve the DNPH grafting to TiO₂ surface. Modified adsorbents were characterized by SEM, TEM, XRD, EDX and FTIR. Since the COD level in wastewaters including formaldehyde is considerable, it is necessary to determine the COD content of the synthetic wastewater. In order to determine the optimal removal conditions, the effect of contact time (60-210 min), pH (4-10) and adsorbent dosage (0.5-1.5 g/L) on adsorption and COD removal efficiencies were studied, using response surface method. EDX and FTIR analysis confirmed the presence of nitrogen-containing functional groups on the modified TiO₂ surface. The maximum formaldehyde adsorption and COD removal efficiencies by modified TiO₂ were about 15.65 and 7.35% higher than the unmodified nanoparticles respectively. Therefore, the grafting of nano-TiO₂ with DNPH would greatly improve its formaldehyde adsorption efficiency. The optimum conditions determined for a maximum formaldehyde removal of 99.904% and a COD reduction of 94.815% by TiO₂/SDS/DNPH nanocomposites were: adsorbent dosage 1.100 g/L, pH 7.424 and the contact time 183.290 min.

• 공업화학
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• 제28권1호
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• pp.50-56
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• 2017

포름알데하이드는 무색, 무취의 유독성 물질로 다양한 방법을 통하여 포름알데하이드를 제거할 수 있는 방법들이 많이 보고되었다. 본 논문에서는 생물학적 효소 반응 및 화학적 흡착 촉매 반응에 의한 포름알데하이드의 제거 효율을 비활성을 통해 비교하였다. 첫째, Escherichia coli K12포름알데하이드 탈수소화 효소(Formaldehyde dehydrogenase, FDH)를 Escherichia coli BL21(DE3)에 클로닝하여 발현 및 분리하였다. FDH 효소 활성($k_{cat}/K_m$)은 $2.49{\times}10^3sec^{-1}mM^{-1}$로 측정되었으며, 비활성은 8.69 U/mg으로 측정되었다. 둘째, 화학적 흡착 및 화학 촉매를 이용한 포름알데하이드의 제거 효율도 동시에 진행하였다. 본 논문에서는 활성탄과 제올라이트, KI 및 KOH로 처리한 활성탄과 제올라이트를 화학적 포름알데하이드 흡착제로 사용하였으며 $Pd/TiO_2$ 산화 촉매를 이용하여 포름알데하이드의 산화 반응 효율을 결정하였다. 결론적으로 본 논문에서 수행한 화학적 흡착 및 산화 촉매 반응의 경우 대략 50%의 비슷한 수준의 포름알데하이드 제거 효율을 보였으며, 특히 비활성의 경우 탈수소화효소의 비활성이 0.01-0.26 U/g 수준의 화학적 흡착 및 산화 촉매보다 월등히 높게 측정되었다.

• 한국조경학회지
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• 제35권2호통권121호
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• pp.49-54
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• 2007

This research was performed to investigate the effect of formaldehyde removal and confirm the utility of plants as indoor environment improvement systems. The plant materials used in this study were Fatsia japonica, Ardisia japonica, Ardisia pusilla and Davallia mariesii. Plants were placed in an airtight chamber under artificial formaldehyde. The initial formaldehyde concentration in the chamber was $500{\pm}30ppb$, and the conditions of $1,500{\sim}2,000lux$ light, $25{\pm}5^{\circ}C$ temperature and $80{\sim}90%$ humidity were maintained. Each chamber was treated as no plant, plant-only and Plant+soil. The total leaf number for Davallia mariesii, Ardisia japonica, Ardisia pusilla, and Fatsia japonica was 40.8, 48.6, 62.3, and 11.8 respectively. The total leaf space n of those plant materials were $2,385cm^2,\;1,252cm^2,\;2,468cm^2\;and\;1,262cm^2$ respectively. The formaldehyde concentration was reduced to $80{\sim}90%$ of the initial concentration in plant-only and Plant+Soil treatment chamber of all species in 12 hours. In the plant-only chamber, Fatsia japonica had removed formaldehyde density by 95% after 12 hours while Ardisia japonica had removed 90%. In the case of Ardisia pusilla, the early removal rate was higher in the plant-only treatment chamber than the Plant+Soil treatment chamber. The formaldehyde removal rate of Davallia mariesii was 98% after 12 hours. In the Plant+Soil treatment chamber, the amount of removal of formaldehyde per time of Davallia mariesii, Ardisia japonica, Ardisia pusilla, and Fatsia japonica was 20.42ppb/hr, 16.28ppb/hr, 2.5.42ppb/hr, 10.28ppb/hr respectively. In the plant-only, That was 22.50ppb/hr, 20.97ppb/hr, 20.83ppb/hr, 20.97ppb/hr respectively.

• 한국대기환경학회지
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• 제12권3호
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• pp.315-322
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• 1996

Recently, hospital acquired infections have an increase interest as a public problems, which are caused of indoor pollutants in hospital. Microorganisms, ethylene oxide, formaldehyde, and anesthetic gases are main hazardous pollutants in hospital. The possible pathways of the infection are a respiratory channel as well as a blood channel. The blood channel is concerned since these pollutants might be dissolved into the Ringer's solution. The objective of this research was to evaluate the removal efficiencies of adsorption trap for formaldehyde and microorganisms as indoor pollutants which permeated into the Ringer's solution. Dissolved formaldehyde in the solution was increased with the injection dose time. The amount of dissolved formaldehyde was 67.5 $\pm$ 9.5% in Ringer's solution when injection dose time was controlled about 7hrs. An adsorption trap was designed for preventing formaldehyde and microorganisms to be permeated into Ringer's solution. The adsorption trap was packed with 0.4g of active carbon (60/80 mesh) in a sterilized plastic tube (7.79 cm length, 0.46 cm i.d.) and both ends were packed with glass wool. Devised infusion set equipped with the adsorption trap showed 99.9% of removal efficiency for formaldehyde. Microorganism numbers detected on sterilized water for injection and 5% dextrose infusion used in the hospital were 2,695 $\times 10^3$ cells/l and 4,190 $\times 10^3$ cells/l, respectively. Removal efficiency by the adsorption trap was 92.3 $\pm$ 8.5% as for microorgnisms.

• 환경위생공학
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• 제20권4호통권58호
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• pp.51-58
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• 2005

Photocatalytic degradation using $TiO_2$ Particles suspended in a reactor was experimentally performed to degrade the formaldehyde of indoor pollutants. Exponential increase of degradation appears to prove light availability due to the scattering of W light by particles themselves. Comparative removal studies of formaldehyde were done in both cases of dipping and spraying immobilized techniques of $TiO_2$ Particles suspended in solution. Experiments were performed under several different experimental conditions such as initial concentration of formaldehyde, UV intensity and concentration of photocatalysts. Optimal conditions to degrade formaldehyde were obtained under the conditions of $30\;mg/cm^2$ concentration of catalyst and UV intensity of 30 Watt at the distance of 30 cm using immobilized technique by dipping coating.

• 토지주택연구
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• 제10권2호
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• pp.45-51
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• 2019

The purpose of this study was to examine the performance of formaldehyde removal from building materials using catechin contained in ginkgo leaf. A small chamber method was used to set up one control group and three experimental groups. As a result, it showed a reduction of formaldehyde from at least 73.5% to 77% when it was increased by 0.4g compared to the control (0g). In addition, it was confirmed by linear regression analysis that the amount of ginkgo leaf and the amount of formaldehyde emission were negatively correlated. Therefore, it was confirmed that the amount of formaldehyde emission was affected by ginkgo leaf.

• 한국환경과학회지
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• 제16권2호
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• pp.197-202
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• 2007

Formaldehyde is a typical indoor air pollutant that has numerous adverse health problems in modern living conditions. Phytoremediation that use plants to remove contaminants from polluted media can be applied to improve indoor air quality. Two sets of experiments; 1) two rooms in newly built auditorium and 2) a bed room in 2-year-old apartment; were performed to investigate plant effects on indoor formaldehyde concentration. It was observed from the experiments that plant can help decontaminating formaldehyde at low concentration level (0.1 ppm) but the effects decreased considerably at hish concentration (1ppm). The purification effects of indoor plant also showed the periodic pattern due to its physiological activity. More purification was observed as increasing plant density in the bed room but the formaldehyde concentration returned the original concentration level in two days after removing plants. It was suggested from the results that air purification using plants is an effective means of reduction on indoor formaldehyde level, though, reduction of source is highly desirable when the concentration level is high. The results also suggest that introducing supplementary purifying aids and/or efficient ventilation could be considered due to periodic removal pattern of plant.

• Carbon letters
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• 제19권
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• pp.79-88
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• 2016

As a replacement for activated carbon, biochar was synthesized and used for the adsorptive removal of formaldehyde and nitrogen oxide. Biochar was produced from the fast pyrolysis of the red marine macro alga, Pyropia tenera. The P. tenera char was then activated with steam, ammonia and KOH to alter its characteristics. The adsorption of formaldehyde, which is one of the main indoor air pollutants, onto the seaweed char was performed using 1-ppm formaldehyde and the char was activated using a range of methods. The char activated with both the KOH and ammonia treatments showed the highest adsorptive removal efficiency, followed by KOH-treated char, ammonia-treated char, steam-treated char, and non-activated char. The removal of 1000-ppm NO over untreated char, KOH-treated char, and activated carbon was also tested. While the untreated char exhibited little activity, the KOH-treated char removed 80% of the NO at 50℃, which was an even higher NO removal efficiency than that achieved by activated carbon.

• Journal of Applied Biological Chemistry
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• 제42권2호
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• pp.81-84
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• 1999

Blood glue was prepared to reutilize porcine blood. Plasma proteins after lyophilization were treated by addition of wood flour, sodium hydroxide, sodium silicate, and hydrated lime to make blood glue with a suitable adhesivity. Characteristics of the prepared blood glue was monitored by measuring the viscosity with time, and the relationship between degree of hydrolysis of plasma proteins by addition of various amounts of sodium hydroxide and adhesivity was studied. To prevent the emission of formaldehyde during manufacturing of plywood by blood glue, the cross-linking reaction of plasma protein with formaldehyde was also examined. Fourier transform infrared, circular dichroism, and fluorescence spectroscopy study showed that blood plasma proteins react with formaldehyde, resulting in removal of formaldehyde by cross-linking reaction.

• 대한환경공학회지
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• 제22권12호
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• pp.2135-2139
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• 2000

시아노구아니딘-포름알데히드 수지에 의한 음이온성 콜로이드 입자의 응집현상은 음이온성 입자의 표면전하와 디아미노메틸렌우레아(diaminomethylene urea: DU) 이온과의 전기적인 작용에 기인한다고 보고되어 있다. 본 논문에서는 음이온성 염료폐수를 응집처리하기 위하여 100~500 nm의 양이온성 시아노구아니딘-포름알데히드 수지를 합성하였고, 응집제 수용액의 pH가 낮을수록 응집제의 Zeta potential은 높게 측정되었다. 농도 0.4 g/L 반응성 염료폐수를 응집처리하였을 경우 pH가 3, 5, 7, 9, 11 중에서 pH가 3인 조건이 다른 pH조건보다 COD, 색도 제거율이 높게 나타났으며, pH 3인 조건에서 400 ppm 주입시 COD 74%, 색도 90% 정도 제거할 수 있었다.