• Textile Coloration and Finishing
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• v.3 no.2
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• pp.34-42
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• 1991

The effects of electrolyte on dyeing properties of cotton fiber with Congo Red have been studied at 90, 70 and $40^{\circ}C$. Each dyeing carried into an infinite bath with $1\times10^{-4}$ mol/l of Congo Red and with various concentration of electrolytes. The results obtained from this study were as follow; 1. The equilibrium adsorption of dye $(C_\infty)$ values decreased with increasing dyeing temperature, $C_\infty$ values increased in the order KCl>NaCl>LiCl. 2. The values of apparent diffusion coefficients $(D_a)$ increased with increasing dyeing temperature, but $D_a$ values decreased in the order KCl$D_a$ values decreased with increasing electrolyte concentration. 4. Effect of electrolytes decreased with increasing dyeing temperature. 5. The values of standard affinities of dyeing $(-\triangle\mu^{\circ})$, the standard heats of dyeing $(-\triangleH^{\circ})$, and the standard entropies $(-\triangleS^{\circ})$, increased in the order KCl>NaCl>LiCl. 6. Equilibrium adsorption isotherm curve were Freundlich type, and in the Equation y=a.x$^{n}$ , the values of a and n increased in the order KCl>NaCl>LiCl. 7. The value of $-\triangle\mu^{\circ}$, $-\triangleH^{\circ}$, and $-\triangleS^{\circ}$, decreased with increasing electrolyte concentration.

• Journal of Pharmaceutical Investigation
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• v.27 no.1
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• pp.39-49
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• 1997

Nicotinic acid was mixed with glass powders such as controlled pore glass (CPG), glyceryl controlled pore glass (GPG) and glass beads (GB) at room temperature. The physicochemical properties of nicotinic acid in the various mixtures were examined by differential thermal analysis, X-ray diffraction study. Infrared spectroscopy and BET gas adsorption measurements. The peak area at the melting point from the various mixtures of nicotinic acid and CPG was increased with an increase of nicotinic acid concentration while the broad peak area was remained unchanged in the DTA curve. As shown in the powder X-ray diffraction patterns, the crystalline peaks of nicotinic acid disappeared in mixture with CPG, suggesting the interaction of nicotinic acid and porous powders. It was found that the larger the content of CPG, the higher the ratio of an amorphous state to a crystalline state. BET isotherm showed that as the amount of nicotinic acid was increased, the specific surface area was reduced proportionally to nicotinic acid content of up to 40% and remained constant thereafter. Sublimation of nicotinic acid from the mixture of nicotinic acid and CPG was examined. A large quantity of nicotinic acid was retained in the mixture when stored on various temperatures in vacuo for 10 hours. The nicotinic acid mixtures with CPG or GPG showed a high dissolution rates of nicotinic acid in aqueous solution, especially in the initial dissolution stage. CPG is expected to be a good pharmaceutical excipient to reduce the crystallinity of drugs and to prevent sublimation of drugs.

• Carbon letters
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• v.12 no.4
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• pp.236-242
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• 2011

The oxyfluorination effects of activated carbon nanofibers (OFACFs) were investigated for $CO_2$ storage. Electrospun CFs were prepared from a polyacrylonitrile/N,N-dimethylformamide solution via electrospinning and heat treatment. The electrospun CFs were chemically activated in order to generate the pore structure, and then oxyfluorination was used to modify the surface. The samples were labeled CF (electrospun CF), ACF (activated CF), OFACF-1 ($O_2:F_2$ = 7:3), OFACF-2 ($O_2:F_2$ = 5:5) and OFACF-3 ($O_2:F_2$ = 3:7). The functional group of OFACFs was investigated using X-ray photoelectron spectroscopy analysis. The C-F bonds formed on surface of ACFs. The intensities of the C-O peaks increased after oxyfluorination and increased the oxygen content in the reaction gas. The specific surface area, pore volume and pore size of OFACFs were calculated by the Brunauer-Emmett-Teller and density functional theory equation. Through the $N_2$ adsorption isotherm, the specific surface area and pore volume slightly decreased as a result of oxyfluorination treatment. Nevertheless, the $CO_2$ adsorption efficiency of oxyfluorinated ACF improved around 16 wt% due to the semi-ionic interaction effect of surface modificated oxygen functional groups and $CO_2$ molecules.

• Korean Journal of Materials Research
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• v.20 no.5
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• pp.252-256
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• 2010

The study was done to change the morphology and pore size of SBA-15 silica, and the characteristics of SBA-15 silica were investigated with TG-DSC, XRD, SEM, TEM and N2 adsorption-desorption under changing aging conditions. SBA-15 silica having a 2D-hexagonal structure was synthesized and confirmed by SEM and TEM. The structure of mesoporus silica SBA-15 showed a pore having regularly formed hexagonal structure and a passage having a cylindrical shape. This result is in good agreement with the pore forming in XRD and cylindrical shape of the structure in $N_2$ adsorption-desorption isotherm. SBA-15 silica showed a large BET surface area of $603-698\;m^2/g$, a pore volume of $0.673-0.926\;cm^3/g$, a large pore diameter of 5.62-7.42 nm, and a thick pore wall of 3.31-4.37 nm. This result shows that as the aging temperature increases, the BET surface area, pore volume, and pore diameter increase but the pore wall thickness decreases. The BET surface areas in SM-2 and SM-3 are as large as $698\;m^2/g$. However, SM-2 has a large surface area and forms a thick pore wall, when the aging temperature is $100^{\circ}C$ and is synthesized into stable mesoporous SBA-15 silica.

• Journal of Microbiology and Biotechnology
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• v.22 no.12
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• pp.1673-1680
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• 2012

In this study, DEAE-corncobs [delignified corncob grits derivatized with 2-(diethylamino)ethyl chloride hydrochloride ($DEAE{\cdot}HCl$)] were prepared as a carrier to immobilize yeast (Saccharomyces cerevisiae) for ethanol production. The immobilized yeast cell reactor produced ethanol under optimized $DEAE{\cdot}HCl$ derivatization and adsorption conditions between yeast cells and the DEAE-corncobs. When delignified corncob grit (3.0 g) was derivatized with 0.5M $DEAE{\cdot}HCl$, the yeast cell suspension ($OD_{600}$ = 3.0) was adsorbed at >90% of the initial cell $OD_{600}$. This amount of adsorbed yeast cells was estimated to be 5.36 mg-dry cells/g-DEAE corncobs. The $Q_{max}$ (the maximum cell adsorption by the carrier) of the DEAE-corncobs was estimated to be 25.1 (mg/g), based on a Languir model biosorption isotherm experiment. When we conducted a batch culture with medium recycling using the immobilized yeast cells, the yeast cells on DEAE-corncobs produced ethanol gradually, according to glucose consumption, without cells detaching from the DEAE-corncobs. We observed under electron microscopy that the yeast cells grew on the surface and in the holes of the DEAE-corncobs. In a future study, DEAE-corncobs and the immobilized yeast cell reactor system will contribute to bioethanol production from biomass hydrolysates.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.1
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• pp.136-142
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• 2007

Recent publications have paid attention on the utilization of solid reagents for the removal of substances causing eutrophication, in particular $PO_4^{3-}$ ions. The adsorption of dissolved inorganic phosphate on slag produced by the refining process of iron ore was fundamentally studied for suppressing the liberation of phosphate from wastewater. This study has been conducted in order to find a possibility to improve the phosphate removal and to evaluate the phosphate removal variation to form hydroxyapatite, when the converter slag is used for phosphate removal. The result shows that the converter slag can be applied to remove phosphate using Freundlich isotherm. The size of converter slag, $2{\sim}0.425 mm$ was more efficient than $2{\sim}4.75mm$ to remove phosphate. In particular, 1 mg/L of phosphate can be removed up to 80% of the initial concentration for the continuous column experiment.

• International Journal of Highway Engineering
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• v.9 no.3
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• pp.75-82
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• 2007

Washed wastewater generated from the intermittent cleaning process of the three tunnel sites located in the Seoul area showed high concentrations of SS, $COD_{Cr}$, T-N, $NH_3-N$, $NO_3-N$, Zn, Cu, Cr(+6), Mn, Mg, Phenol, $CN^-$ and E-Coli based on the water quality analysis. These characteristics of the deteriorative wastewater depend on the sampling method, cleaning frequency, released amount of washing water, inner material of tunnel wall, traffic volume, and type of drainage systems. Gravitational separation experiment of SS with collected tunnel wastewater showed considerable removal of pollutants such as 80% of $COD_{Cr}$, 30% of T-N and 90% of T-P simultaneously. GAC isotherm test was conducted to remove dissolved portion of the pollutants, and resulted in high removal efficiencies above 80% of $COD_{Cr}$, T-N, Zn, Cu, Mn, Phenol, CN in the experimental condition of GAC dosage of $50g/1/{\ell}$.

• Corrosion Science and Technology
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• v.22 no.2
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• pp.73-89
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• 2023

Due to continuous promotion of green alternatives to toxic petrochemicals by government policies, research efforts towards the development of green corrosion inhibitors have intensified recently. The objective of the current work was to develop novel green and sustainable corrosion inhibitors derived from 4-aminoantipyrine to effectively prevent corrosion of mild steel in corrosive environments. Gravimetric methods were used to investigate corrosion inhibition of 4-((furan-2-ylmethylene)amino)antipyrine (FAP) and 4-((pyridin-2-ylmethylene)amino)antipyrine (PAP) for mild steel in 1 M HCl. FAP and PAP were subjected to quantum chemical calculations using density functional theory (DFT). DFT was used to determine the mechanism of mild steel corrosion inhibition using inhibitors tested in HCl. Results demonstrated that these tested inhibitors could effectively inhibit mild steel corrosion in 1.0 M HCl. At 0.0005 M, these inhibitors' efficiencies for FAP and PAP were 93.3% and 96.5%, respectively. The Langmuir adsorption isotherm was obeyed by these inhibitors on the mild steel surface. Values of adsorption free energies, ΔG^o_ads, revealed that FAP followed chemical and physical adsorptions.

• Journal of Korean Society of Water and Wastewater
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• v.37 no.6
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• pp.375-382
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• 2023

The binary oxide adsorbent using Fe and Mn (Fe-Mn) has been prepared by precipitation method to enhance the removal of phosphate. Different amounts of chitosan, a natural organic polymer, were used during preparation of Fe-Mn as a stabilizer to protect an aggregation of Fe-Mn particles. The optimal amount of chitosan has been determined considering the separation of the Fe-Mn particles by gravity from solution and highest removal efficiency of phosphate (Fe-Mn10). The application of Fe-Mn10 increased removal efficiency at least 15% compared to bare Fe-Mn. According to the Langmuir isotherm model, the maximum uptake (q_m) and affinity coefficient (b) were calculated to be 184 and 240 mg/g, and 4.28 and 7.30 L/mg for Fe-Mn and Fe-Mn10, respectively, indicating 30% and 70% increase. The effect of pH showed that the removal efficiency of phosphate was decrease with increase of pH regardless of type of adsorbent. The enhanced removal efficiency for Fe-Mn10 was maintained in entire range of pH. In the kinetics, both adsorbents obtained 70% removal efficiency within 5 min and 90% removal efficiency was achieved at 1 h. Pseudo second order (PSO) kinetic model showed higher correlation of determination (R²), suggesting chemisorption was the primary phosphate adsorption for both Fe-Mn and Fe-Mn10.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.4
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• pp.404-411
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• 2007

Adsorption performance of odorous compounds such as geosmin and 2-MIB on granular activated carbon were evaluated in this study. The coal-based activated carbon was found more effective than other carbons in adsorption of geosmin and 2-MIB. The wood-based virgin activated carbon was less effective than coconut- and coal-based carbon in adsorption nevertheless having larger pore volume and specific surface area than others carbons. The maximum adsorption capacity(X/M) of coal-based activated carbon for geosmin and 2-MIB was $1.2\sim1.9$ and $2.1\sim2.6$ times larger than coconut- and wood-based virgin activated carbon, respectively. Carbon usage rate (CUR) of coal-, coconut- and wood-based virgin activated carbons for geosmin and 2-MIB were 1.72 and 1.44 g/day, 1.72 and 2.05 g/day and 2.12 and 1.90 g/day, respectively. In the evaluation of adsorption isotherm of geosmin and 2-MIB for coal-, coconut- and wood-based virgin activated carbons, k value of 2-MIB was lower than geosmin, It menas 2-MIB is more difficult to remove by activated carbon adsorption than geosmin. The relationship of max. adsorption versus total pore volume of coconut- and wood-based virgin and used activated carbon for geosmin and 2-MIB were $y=264,459\times-79,047(R^2=0.95)$, $y=319,650\times-101,762(R^2=0.93)$.