• Korean Journal of Environmental Agriculture
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• v.15 no.3
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• pp.391-398
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• 1996

The pretreatment of bark powder with sodium hydroxide and formalin showed the most excellent adsorption ratio, but this method could not practically be used because of the occurrence of dark-colored pigments in filtrates during pretreatment. Instead, acid and formalin were the most affirmative and effective among the pretreatment methods tested, and could be used for this purpose. Among tested species, Quercus acutissima and Robinia pseudo-accacia showed the largest amount of metal adsorption, and $Pb^{2+}$ was the best(83 to 96%) among the four heavy metals tested. The order of adsorption ratios other metals was as follows; $Cu^{2+}$ > $Zn^{2+}$ > $Cd^{2+}$, and the ratio was approximately 45 to 55%. In addition, as the substrate amount increased, the amount of adsorbed heavy metals in subtrates gradually increased, but the adsorbed amount was not proportional to the substrate amount. The order of heavy metal adsorption was as follows; $Pb^{2+}$ > $Cu^{2+}$ > $Cd^{2+}$ > $Zn^{2+}$. Depending on flow rate and column size, pine bark power adsorbed more heavy metals in the 5ml/min flow rate and 3.5cm column size rather than the 10ml/min and 2.0cm. However, oak bark power showed contrary results compared with pine bark powder. The adsorption of $Pb^{2+}$ occurred rapidly in the incipient stagte. Even though bark powders were repeatedly used three times, there was no change in the adsorption ratio(45%), but after four times, the adsorption ratio was significantly reduced to 35%.

• Applied Chemistry for Engineering
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• v.9 no.4
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• pp.574-578
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• 1998

Electrochemical Ion Exchang(EIX) electrode containing Amberlite IRP-64 as a cation ion exchange resin and Stylene-Buthylene-Rubber(SBR) as a binder was fabricated by the compressed diecasting method. The adsorption and elution characteristics in copper sulfate solution were investigated at the various electrode potentials and electrolyte pHs. In the adsorption process, it was found that the maximum adsorption rate of copper was obtained at -1800 mV and the ratio of adsorption was 92% during 90 min. In the elution process, the elution rate of copper was increased in proportion to anodic potential in the present experimental range and the ratio of elution was 88% during 50 mins at 3600 mV. The adsorption and elution processes were significantly affected by the variation of local pH in the vicinity of electrochemical ion exchange electrode. The higher performances of adsorption and elution were elution were obtained at basic and acidic eletrolytes.

• Korean Chemical Engineering Research
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• v.59 no.4
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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.

• Clean Technology
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• v.25 no.3
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• pp.198-205
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• 2019

The adsorption equilibrium, kinetic, and thermodynamic parameters of brilliant green adsorbed by coconut based granular activated carbon were determined from various initial concentrations ($300{\sim}500mg\;L^{-1}$), contact time (1 ~ 12 h), and adsorption temperature (303 ~ 323 K) through batch experiments. The equilibrium adsorption data were analyzed by Langmuir, Freundlich, Temkin, Harkins-Jura, and Elovich isotherm models. The estimated Langmuir dimensionless separation factor ($R_L=0.018{\sim}0.040$) and Freundlich constant ($n^{-1}=0.176{\sim}0.206$) show that adsorption of brilliant green by activated carbon is an effective treatment process. Adsorption heat constants ($B=12.43{\sim}17.15J\;mol^{-1}$) estimated by the Temkin equation corresponded to physical adsorption. The isothermal parameter ($A_{HJ}$) by the Harkins-Jura equation showed that the heterogeneous pore distribution increased with increasing temperature. The maximum adsorption capacity by the Elovich equation was found to be much smaller than the experimental value. The adsorption process was best described by the pseudo second order model, and intraparticle diffusion was a rate limiting step in the adsorption process. The intraparticle diffusion rate constant increased because the dye activity increased with increases in the initial concentration. Also, as the initial concentration increased, the influence of the boundary layer also increased. Negative Gibbs free energy ($-10.3{\sim}-11.4kJ\;mol^{-1}$), positive enthalpy change ($18.63kJ\;mol^{-1}$), and activation energy ($26.28kJ\;mol^{-1}$) indicate respectively that the adsorption process is spontaneous, endothermic, and physical adsorption.

• Clean Technology
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• v.27 no.1
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• pp.47-54
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• 2021

The adsorption of Acid Fuchsin (AF) on granular activated carbon (GAC) was investigated for isothermal adsorption and kinetics and thermodynamic parameters by experimenting with the initial concentration, contact time, temperature, and pH of the dye as adsorption parameters. In the pH effect experiment, the adsorption of AF on activated carbon showed a bathtub type with increased adsorption at pH 3 and 11. The adsorption equilibrium data of AF fit well with the Freundlich isotherm model, and the calculated separation factor (1/n) value was found in which activated carbon can effectively remove AF. The pseudo-second-order kinetic model fits well within 7.88% of the error percent in the adsorption process. According to Weber and Morris's model plot, it was divided into two straight lines. The intraparticle diffusion rate was slow because the stage 2 (intraparticle diffusion) slope was smaller than that of stage 1 (boundary layer diffusion). Therefore, it was confirmed that the intraparticle diffusion was a rate-controlling step. The activation energy of AF (13.00 kJ mol-1) corresponded to the physical adsorption process (5 - 40 kJ mol-1). The free energy change of the AF adsorption by activated carbon showed negative values at 298-318 K. As the spontaneity increased with increasing temperature. The adsorption of AF was an endothermic reaction (ΔH = 22.65 kJ mol-1).

• Journal of Environmental Science International
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• v.23 no.9
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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.

• Journal of the Korean Society of Safety
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• v.17 no.1
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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.

• Textile Coloration and Finishing
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• v.17 no.4 s.83
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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.

• Journal of The Korean Society of Agricultural Engineers
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• v.56 no.3
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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.

• Textile Coloration and Finishing
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• v.30 no.1
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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.