• 한국재료학회지
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• 제22권3호
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• pp.140-144
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• 2012

Compared with bulk material, quantum dots have received increasing attention due to their fascinating physical properties, including optical and electronic properties, which are due to the quantum confinement effect. Especially, Luminescent CdSe quantum dots have been highly investigated due to their tunable size-dependent photoluminescence across the visible spectrum. They are of great interest for technical applications such as light-emitting devices, lasers, and fluorescent labels. In particular, quantum dot-based light-emitting diodes emit high luminance. Quantum dots have very high luminescence properties because of their absorption coefficient and quantum efficiency, which are higher than those of typical dyes. CdSe quantum dots were synthesized as a function of the synthesis time and synthesis temperature. The photoluminescence properties were found strongly to depend on the reaction time and the temperature due to the core size changing. It was also observed that the photoluminescence intensity is decreased with the synthesis time due to the temperature dependence of the band gap. The wavelength of the synthesized quantum dots was about 550-700 nm and the intensity of the photoluminescence increased about 22~70%. After the CdSe quantum dots were synthesized, the particles were found to have grown until reaching a saturated concentration as time increased. Red shift occurred because of the particle growth. The microstructure and phase developments were measured by transmission electron microscopy (TEM) and X-ray diffractometry (XRD), respectively.

• Journal of the Korean Wood Science and Technology
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• 제52권5호
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• pp.504-523
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• 2024

Timber industry waste is being examined for cellulose manufacturing to give important benefits. The study's goal is to investigate the properties of cellulose powder derived from sawdust waste after it has been reinforced with ferrous-ferric oxide nanoparticles (Fe₃O₄-NPs). Sawdust cellulose powder was produced from Sengon (Albizia chinensis) wood waste in this study. The crushed sawdust waste is handled with alkalization and bleaching. Cellulose powder is then reinforced with Fe₃O₄-NPs at 10 wt.%, 20 wt.%, and 30 wt.%. The magnetic cellulose powder was analysed by X-ray diffraction, Fourier Transform Infrared, scanning electron microscopy morphology, magnetic vibrating sample magnetometer, Brunauer-Emmett teller, and adsorption tests for Methylene Blue and Congo Red dyes. Structure study identifies sawdust as cellulose 1β, with peaks at 14°, 16°, and 22° diffraction angles. The addition of Fe₃O₄-NPs reduces the crystalline index of sawdust cellulose powder from 68.50% to 63.38%, and functional group bond analysis revealed many peak shifts indicating a change in the chemical bonds of magnetic cellulose powder. Incorporating Fe₃O₄-NPs into sawdust cellulose powder confers magnetic and superparamagnetic properties to the sawdust cellulose. Similarly, the surface texture of magnetic cellulose seems rougher as the surface area increases. These parameters imply a 31.8% increase in Congo Red adsorption, using adsorption kinetics based on the pseudo-first-order model.

• 한국환경농학회지
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• 제18권3호
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• pp.250-258
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• 1999

익산 제 2공단은 1995년 조성 후 생산활동이 진행됨에 따른 토양의 중금속 함량을 비오염지의 자연토양 중 함량과 비교하고, 산업활동의 유형에 따른 토양중 중금속 함량 변화와의 관계를 구명하기 위하여 주로 표층토를 중심으로 $0{\sim}3\;cm$, $3{\sim}6\;cm$ 토양층에 있는 Cd, Cu, Ni, Pb 및 Zn의 함량을 조사${\cdot}$분석한 결과는 다음과 같다. 1. Cd의 함량의 경우 $0{\sim}3\;cm$ 층은 $0.07\;{\sim}\;4.375\;ppm$ 범위로 평균 0.516 ppm, $3{\sim}6\;cm$ 층은 $0.07{\sim}8.52\;ppm$ 범위로 평균 0.380 ppm 이었으며, 화학제품, 염료 및 금속제품을 생산하는 지역이 높았다. 2. Cu의 함량 분포의 경우 $0{\sim}3\;cm$ 층은 $0.61\;{\sim}\;42.62\;ppm$ 범위로 평균 11.087 ppm, $3{\sim}6\;cm$ 층은 $0.16{\sim}35.45\;ppm$ 범위로 평균 7.578 ppm 이었으며, 금속제품을 생산하는 지역이 주로 높았다. 3. Ni의 함량 분포의 경우 $0{\sim}3\;cm$ 층은 $0.19\;{\sim}\;15.93\;ppm$ 범위로 평균 5.525 ppm, $3{\sim}6\;cm$ 층은 $0.39{\sim}15.59\;ppm$ 범위로 평균 5.310 ppm 이었으며, 금속 및 화학제품을 생산하는 지역이 주로 높았다. 4. Pb의 함량 분포의 경우 $0{\sim}3\;cm$ 층은 $3.10\;{\sim}\;55.75\;ppm$ 범위로 평균 23.543 ppm, $3{\sim}6\;cm$ 층은 $3.35{\sim}46.55\;ppm$ 범위로 평균 19.198 ppm 이었으며, 화학제품 및 금속제품을 생산하는 지역이 높았다. 5. Zn의 함량 분포의 경우 $0{\sim}3\;cm$ 층은 $26.50\;{\sim}\;943.00\;ppm$ 범위로 평균 158.329 ppm, $3{\sim}6\;cm$ 층은 $35.45{\sim}882.45\;ppm$ 범위로 평균 127.914 ppm 이었으며, 화학제품, 염료 및 금속제품을 생산하는 지역이 높았다. 이상의 결과를 토대로 세계의 비오염 토양 함량수준과 본조사지역의 평균함량을 비교하면 Cu, Ni은 비오염 수준이었으나, Cd은 기준치를 약간 넘었고, Pb과 Zn은 기준치보다 훨씬 높아 익산 제2공단의 오염정도는 산업(화학제품, 염료 및 금속 제품을 생산)유형에 따라 차이가 있음을 알 수 있었다.

• Bulletin of the Korean Chemical Society
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• 제33권10호
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• pp.3184-3190
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• 2012

Color impurity in industrial effluents pose a significant risk to human health and the environment, so much effort has been expended to degrade them using various methods, including the use of clay minerals as adsorbent. The purpose of this study was to advance understanding of the mechanisms for the removal of methylene blue (MB) from aqueous solutions onto montmorillonite as an adsorbent. Preliminary experiments showed that montmorillonite was effective for this purpose and adsorption equilibrium could be reached in about 24 h. Adsorption capacity of the clay decreased with increase in temperature and ionic strength, and increased with in pH. The fitness of equilibrium data to common isotherm equations such as the Langmuir, Freundlich, Elovich, Temkin and Dubinin-Radushkevich were tested. The Langmuir equation fitted to equilibrium data better than all tested isotherm models. Thermodynamic activation parameters such as ${\Delta}G^0$, ${\Delta}S^0$ and ${\Delta}H^0$ were also calculated and results were evaluated. As result montmorillonite clay was found as effective low cost adsorbent for removal of cationic dyes from waste waters.

• 공업화학
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• 제4권3호
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• pp.583-590
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• 1993

키토산 유도체 중 약한 음이온 교환기를 갖는 O-Diethylaminoethyl 키토산을 제조하여, 이를 크로마토그래피의 고정상으로 이용하여 생체단백질의 하나이며 등전점이 서로 다른 알부민과 라이소자임의 분리에 응용하였다. 우선 산성 염료와 염기성 염료를 이용하여 고정상으로서의 응용 가능성을 검토하였고 용매에 의한 극성효과도 검토하였다. 이것을 토대로 하여 크로마토그래피의 분리에 미치는 제반인자를 구하였다. 용매로써는 물과 메탄을 공용매를 사용하였고 이 경우 극성값이 증가할수록 분리능이 증가하였으며 가장 좋은 분리능은 치환도가 0.23인 경우 분리도가 1.42였다.

• 공업화학
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• 제17권4호
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• pp.426-431
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• 2006

Poly(methyl methacrylate) (PMMA)의 착색을 위하여 아크릴 그리고 비닐설폰기를 가지는 청색 및 오렌지 아조 염료들을 6-bromo-2-cyano-4-nitroaniline과 2,5-dimethoxy-4-(vinylsulfonyl)benzenamine을 3-acrylamido-(N,N-diethylamino) benzene과 3-methyl-(N,N-diethylamino)benzene의 아조 짝지음 반응을 이용하여 각각 합성하였다. 또한 알릴기를 가지는 염료는 비닐설폰과 allylamine과의 반응에 의하여 제조하였다. PMMA의 착색은 아크릴, 비닐설폰 그리고 알릴 작용기를 가지는 염료를 직접 methyl methacrylate (MMA)와 공중합하거나, MMA와 공중합한 고분자염료 및 반응성기가 없는 염료 2를 직접 MMA에 용해하여 중합과 동시에 착색하였다. 3가지로 착색한 PMMA의 염색 견뢰도를 여러 환경 조건에서 염료의 용해도를 비교하여 평가하였다.

• Mycobiology
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• 제41권4호
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• pp.214-220
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• 2013

This study was conducted in order to perform efficient extraction of lignocellulolytic enzymes amylase (EC 3.2.1.1), cellulase (EC 3.2.1.4), laccase (EC 1.10.3.2), and xylanase (EC 3.2.1.8) from spent mushroom compost (SMC) of Pleurotus ostreatus, P. eryngii, and P. cornucopiae. Optimal enzyme recovery was achieved when SMCs were extracted with 50 mM sodium citrate (pH 4.5) buffer at $4^{\circ}C$ for 2 hr. Amylase, cellulase, and xylanase activities showed high values in extracts from P. ostreatus SMC, with 2.97 U/g, 1.67 U/g, and 91.56 U/g, respectively, whereas laccase activity and filter paper degradation ability were highest in extracts from P. eryngii SMC, with values of 9.01 U/g and 0.21 U/g, respectively. Enzymatic activities varied according to the SMCs released from different mushroom farms. The synthetic dyes remazol brilliant blue R and Congo red were decolorized completely by the SMC extract of P. eryngii within 120 min, and the decolorization ability of the extract was comparable to that of 0.3 U of commercial laccase. In addition, laccase activity of the SMC extract from P. eryngii was compared to that of commercial enzymes or its industrial application in decolorization.

• Fibers and Polymers
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• 제5권4호
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• pp.321-326
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• 2004

[ $TiO_2$ ] contents in yarns can influence color yield so that dyeing quality of industrial polyethylene terephthalate (PET) yarns can be improved through the adjustment of $TiO_2$ contents. To evaluate the dyeing performance of color yield, the chips which included the different $TiO_2$ contents of 330,550, and 1,100 ppm respectively were used to produce the yarns of different $TiO_2$ content by a spin-draft machine. The physical and structural properties of the yarns were measured to investigate effect of the $TiO_2$ contents on them. Dye uptake and dyeing rate were also evaluated using a colorimeter to compare the yarns having different TiOz contents. The experimental results showed that there were no appreciable variation in physical and structural properties among the yarn samples and no difference were observed among the dyed fabric samples with regard to dyeing uptake and dyeing rate. However, the color yield of dyed fabrics increased as $TiO_2$ contents decreased in the yarns especially when the fabric samples were dyed to pale shade. The physical reasoning could be proposed on why the yarns having low $TiO_2$ contents appeared to have higher color yield after dyeing.

• 분석과학
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• 제35권4호
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• pp.153-160
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• 2022

A green spectrophotometric method for the determination of cyanide has been proposed using, a green reagent, aqueous extract of blue butterfly pea. The test tube was filled with anthocyanin rich extract (pH 6) and cyanide solution. The reaction was kept constant for 10 minutes at room temperature. The reaction mixture changed color from blue to green as the amount of CN-ions increased. The 620 nm peak intensity increased with CN concentration. Therefore, this wavelength was used for all cyanide analyses. The cyanide calibration curve had a linear range of 0.25-1.00, 1.00-4.00, and 4.00-10.00 mg/L, with a satisfactory correlation coefficient of 0.99 and a LOD of 0.57 mg/L. The recovery ranged from 8.33 to 76.94 percent, indicating that this method is inaccurate at low cyanide concentrations. The intra-day and intermediate precision relative deviations were 0.391-0.871 % and 1.112-1.583 %. An H-bond forms between the C-4 group of the B-carbonyl ring and the HCN molecule according to the B3LYP/TZVP calculation. The method is convenient for cyanide concentrations above the LOQ of 1.09 mg/L, cost-effective, and capable of reducing toxic solvents with acceptable precision. The method could also be used to detect total cyanide in biological, environmental, and industrial waste samples.

• 한국염색가공학회지
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• 제22권4호
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• pp.341-348
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• 2010

Sodium sulfate is commonly added in reactive dyebath in order to increase substantivity of the reactive dye to cellulose fiber by reducing repulsion between anionic dye and fiber. While sodium sulfate is mostly used in solid form, it is inconvenient to dissolve a large amount of powder sodium sulfate. Furthermore, if there is undissolved salt in dyebath it might cause unlevel dyeing. In this study, sodium sulfate in liquid or solid form was used in dyeing of cellulose fabric with reactive dyes of three primary color and the effect of type or amount of sodium sulfate on dyeing and fastness properties was investigated. When the amount of sodium sulfate rose to 30-50 g/l, K/S value of the dyed fabric markedly increased; further rise in sodium sulfate concentration resulted in slow increase in K/S value. For light color, optimum amount was about 30 g/l in solid form and 50-100 g/l in liquid form while, for medium to deep color, it was 50 g/l and 100-150 g/l in solid and liquid form, respectively. When using each optimum amount of salt in solid or liquid form for medium color, shape of dyeing curve as well as exhaustion was similar to each other. On the whole, similar color fastness results were obtained regardless of type or amount of sodium sulfate.