• Korean Chemical Engineering Research
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• 제59권4호
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• pp.493-502
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• 2021

We prepared and investigated a biosynthesized nanoparticulate system with high adsorption and release capacity of letrozole. Silver nanoparticles (AgNPs) were biosynthesized using olive leaf extract. Cysteine was capped AgNPs to increase the adsorption capacity and suitable interaction between nanoparticles and drug. Morphology and size of nanoparticles were confirmed using transmission electron microscopy (TEM). Nanoparticles were spherical with an average diameter of less than 100 nm. Cysteine capping was successfully confirmed by Fourier transform infrared resonance (FTIR) spectroscopy and elemental analysis (CHN). Also, the factors of letrozole adsorption were optimized and the linear and non-linear forms of isotherms and kinetics were studied. Confirmation of the adsorption data of letrozole by cysteine capped nanoparticles in the Langmuir isotherm model indicated the homogeneous binding site of modified nanoparticles surface. Furthermore, the adsorption rate was kinetically adjusted to the pseudo-second-order model, and a high adsorption rate was observed, indicating that cysteine coated nanoparticles are a promising adsorbent for letrozole delivery. Finally, the kinetic release profile of letrozole loaded modified nanoparticles in simulated gastric and intestinal buffers was studied. Nearly 40% of letrozole was released in simulated gastric fluid with pH 1.2, in 30 min and the rest of it (60%) was released in simulated intestinal fluid with pH 7.4 in 10 h. These results indicate the efficiency of the cysteine capped AgNPs for adsorption and release of drug letrozole for breast cancer therapy.

• Bulletin of the Korean Chemical Society
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• 제28권8호
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• pp.1375-1382
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• 2007

A column preconcentration method with pulverized Amberlite XAD-4 loaded with bismuthiol I (BI) has been developed for the determination of trace Cd(II) and Cu(II) in various real samples by flame atomic absorption spectrophotometry. Various experimental conditions, such as the size of XAD-4, adsorption flow rate, amount of bismuthiol I, stirring time for adsorbing bismuthiol I on XAD-4, pH of sample solution, amount of XAD-4- BI, desorption solvent, and desorption flow rate, were optimized. Also, the adsorption capacity and the adsorption rate of Cd(II) and Cu(II) on XAD-4-BI were investigated. The interfering effects of various concomitant ions were investigated, Bi(III), Sn(II) and Fe(III) were found to affect the determination. But the interference by these ions was completely eliminated by adjusting the amount of XAD-4-BI resin to 0.70 g, although the adsorption flow rate was slower. For Cd(II) our proposed technique obtained a dynamic range of 0.5-40 ng mL-1, a correlation coefficient (R2) of 0.9913, and a detection limit of 0.3 ng mL-1. For Cu(II), the corresponding values were 2.0-120 ng mL-1, 0.9921 and 1.02 ng mL-1. To validate this proposed technique, the aqueous samples (stream water, reservoir water, tap water and wastewater), the diluted brass sample and the plastic sample, as real samples, were used. Recovery yields of 91-103% were obtained. These measured data were not different from ICP-MS data at 95% confidence level. Our proposed method was also validated using rice flour CRM (normal, fortified) samples. From the results of our experiment, we found that the technique we present here can be applied to the determination of Cd(II) and Cu(II) in various real samples.

• 청정기술
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• 제25권3호
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• pp.198-205
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• 2019

야자계 입상활성탄에 대한 Brilliant Green의 흡착 평형과 동역학 및 열역학 파라미터들을 다양한 초기농도($300{\sim}500mg\;L^{-1}$), 접촉시간(1 ~ 12 h) 및 흡착온도(303 ~ 323 K)를 변수로 하여 회분식 실험을 통하여 연구하였다. 흡착평형 값들은 Langmuir, Freundlich, Temkin, Harkins-Jura 및 Elovich 식으로 해석하였다. 그 결과는 Langmuir 식에 가장 잘 맞았으며, 평가된 Langmuir 무차원 분리계수 값($R_L=0.018{\sim}0.040$)과 Freundlich 상수값(1/n = 0.176 ~ 0.206)은 활성탄에 의한 Brilliant Green의 흡착이 효과적인 공정임을 보여주었다. Temkin 식에 의해 평가된 흡착열 관련상수($B=12.43{\sim}17.15J\;mol^{-1}$)는 물리흡착에 해당하였다. Harkins-Jura 식에 의한 등온선 매개변수($A_{HJ}$)는 온도가 증가할수록 이종 기공 분포도 증가함을 나타내었고, Elovich 식에 의한 최대흡착용량은 실험값보다 매우 적은 것으로 나타났다. 흡착공정은 유사이차반응속도식에 더 잘 맞았으며, 흡착과정은 입자내 확산이 율속단계였다. 입자내 확산속도 상수는 초기 농도가 커질수록 염료의 운동이 활발해졌기 때문에 증가하였다. 그리고 초기농도가 커질수록 경계층의 영향이 커졌다. Gibbs 자유에너지($-3.46{\sim}-11.35kJ\;mol^{-1}$), 엔탈피($18.63kJ\;mol^{-1}$) 및 활성화에너지($26.28kJ\;mol^{-1}$)는 흡착공정이 자발적이고, 흡열 및 물리흡착임을 나타냈다.

• 청정기술
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• 제27권1호
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• pp.47-54
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• 2021

입상 활성탄(GAC)에 대한 Acid Fuchsin (AF)의 흡착을 염료의 초기농도, 접촉 시간, 온도 및 pH 를 흡착변수로 실험하여 등온흡착과 동력학적, 열역학적 파라미터에 대해 조사하였다. pH 변화실험에서 활성탄에 대한 AF의 흡착은 pH 3과 11에서 모두 흡착이 증가하는 욕조형을 나타냈다. AF의 흡착평형자료는 Freundlich 등온식에 잘 맞았으며, 계산된 분리계수(1/n) 값으로부터 활성탄이 AF를 효과적으로 제거할 수 있다는 것을 알았다. 흡착공정은 유사 이차 반응속도식이 오차율 7.88% 이내로 잘 맞았다. Weber와 Morris 모델의 Polt에 따르면 두 단계의 직선으로 구분되었다. stage 2 (입자내 확산)의 기울기가 stage 1 (경계층 확산)의 기울기 보다 작아서 입자내 확산속도가 느렸다. 따라서 입자 내 확산이 속도지배단계인 것을 확인하였다. AF의 활성화 에너지(13.00 kJ mol-1)는 물리흡착공정(5 ~ 40 kJ mol-1)에 해당하였다. 활성탄에 의한 AF 흡착의 자유에너지 변화는 298 ~ 318 K에서 모두 음의 수치를 나타냈으며, 온도가 증가할수록 자발성이 더 높아졌다. AF 흡착은 흡열반응(ΔH = 22.65 kJ mol-1)으로 나타났다.

• 한국환경과학회지
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• 제23권9호
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• pp.1593-1600
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• 2014

Adsorption and desorption characteristics of the representative 10 kinds components consisting of gasoline vapor on activated carbon were investigated at the temperature range of $-30^{\circ}C{\sim}25^{\circ}C$. The breakthrough curves of each vapors obtained by the Thomas model were well described the breakthrough experimental results of this study. The breakthrough times of each vapors were correlated with the molecular weight, density, and vapor pressure. The breakthrough times had greater correlation with boiling point than molecular weight and density. The slope of the breakthrough curve was a proportional relationship with the rate constant (k) of Thomas model expression. The higher the slope of the breakthrough curve, the rate constant was larger. The biggest slope vapor had the smallest adsorption capacity ($q_e$). Adsorption and desorption characteristics of mixed vapor similar to the gasoline vapor were studied at room temperature ($25^{\circ}C$). The mixed vapor consisting of 9 components; group A (pentane, hexene, hexane), group B (benzene, toluene), group C (octane, ethylbenzene, xylene, nonane) was examined. Group A was not nearly adsorbed because of substitution by group C, and the desorption capacity of group A was smaller than group C. The adsorbed substances were confirmed to be Group C.

• 한국안전학회지
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• 제17권1호
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• pp.54-60
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• 2002

To obtain the breakthrough characteristics for the design of fixed bed adsorption plant, adsorption experiment on granular activated carbon was performed with tharonil in the fixed bed. The pore diffusivity and surface diffusivity of tharonil estimated by the concentration-time curve and adsorption isotherm were $D_s=2.825{\times}10^{-9}cm^2/s,\;D_p=1.26{\times}10^{-5}cm^2/s$, respectively. From comparison of the pore diffusivity and surface diffusivity, it was found that surface diffusion was controlling step for intrapaticle diffusion. The breakthrough curve predicted by constant pattern-linear driving force model were shown to agree with the experimental results. The surface diffusivity and film mass transfer coefficient had no effect on the theoretical breakthrough curve but the adsorption isotherm had fairly influence on it. Appearance time of breakthrough curve is faster with the increase flow rate and inflow concentration of liquid. The utility of granular activated carbon is enhanced with the increase of bed height and with the decrease of inflow rate.

• 한국염색가공학회지
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• 제17권4호
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• pp.27-34
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• 2005

In order to prepare acetate nano filter for the adsorption of nicotine/tar in tobbaco, acetate nano fiber was fabricated by elecrospining from acetate solution dissolved in acetone/DMAc(2/1). Above a critical polymer concentration($15\%$), the nano fiber was formed. The average diameter of nano fiber was decreased with the applied voltage and increased with the feeding rate. Appropriate spinning condition was considered to be $15wt\%$ polymer concentration, 11.25kV applied voltage, 0.6ml/h feeding rate, and 13-15cm TCD. Using the nano fiber, acetate nano filter was fabricated. It showed good nicotine/tar adsorption ability compared with general tobbaco filter. It was considered that the increase of surface area and the development of microporous structure in filter was much affected to the adsorption of nicotine/tar.

• 한국농공학회논문집
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• 제56권3호
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• pp.11-17
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• 2014

We investigated the applicability of steel slag as a capping material in order to minimize phosphorus(P) release into seawater. Steel slag is a byproduct from the iron and steel industries and the use of steel slag has some advantages in respect of both cost and environmental concern. P removal by steel slag were studied in a batch system with respect to changes in contact time and initial concentration. Kinetic adsorption data were described well by pseudo 2nd order model, indicating rate limiting step for P adsorption to steel slag is chemical sorption. Equilibrium adsorption data fitted well to Langmuir isotherm model which describes for single layer adsorption. The maximum P adsorption capacity of steel slag was 7.134 mg-P/L. Increasing the depth of steel slag produced a positive effect on interruption of P release. More than 3 cm of steel slag was effective for blocking P release and 5 cm of steel slag was recommended as the depth for capping of P contaminated marine sediments. Increasing P concentration and flow rate had a negative effect on P removal ratio. It was concluded that the steel slag has a potential capping material for blocking P release from marine sediments.

• 한국염색가공학회지
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• 제30권1호
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• pp.20-28
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• 2018

The near infrared ray camouflage fabric has a near infrared ray reluctance similar to the surrounding environment and has a camouflage effect on the surrounding environment. Synthetic fibers used in military uniforms are difficult to have gastrointestinal function as general commercial dyes, unlike cellulose fibers, which use some commercial vat dyes to impart infrared gastrointestinal function. In this study, we optimized the adsorption pH, temperature and time for NIR dye application for polyester fabrics, and established the optimum concentration for the evaluation of adsorption build-up characteristics. In addition, it is difficult to adsorb it since the polyester material has a dense crystal structure and the NIR dye is bulky. Therefore, a swelling agent used for dyeing meta-aramid fibers with high Tg and high crystallinity was introduced as a separate preparation to increase the affinity to polyester, which is a hydrophobic fiber, to thereby obtain an excellent adsorption rate. As a result of comparing before and after using swelling agent, the adsorption rate difference was 10 times or more when compared with before.

• 한국응용과학기술학회지
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• 제27권3호
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• pp.318-324
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• 2010

In this study, commercial pellet type sorbents for the collection of $CO_2$ from a local municipal waste incinerator were prepared and characterized in terms of adsorption efficiency by varying the operating conditions of a field process. The concentration of $CO_2$ in the flue gas ranged from 8 to 10%, which entered the test packed bed. As a result of this experiment, the sorbent procured from A-company, which is mainly composed of calcium compounds, showed the highest adsorption efficiency. The regeneration efficiency was fairly low, however. It also was found that based on adsorption breakthrough time, the relatively low flow rate of 10 LPM into the bed allowed higher collection efficiency. The higher flow rate of 40 LPM, on the other hand, tended to decrease the retention of the adsorption.