• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2006.05a
• /
• pp.20-22
• /
• 2006

Monolayers of lipids on a water surface have attracted much interest as models of biological membranes, but also as precursors of multilayer systems promising many technical applications. Until now, many methodologies have been developed in order to gain a better understanding of the relationship between the structure and function of the monolayers. Maxwell displacement current (MDC) measurement has been employed to study the dielectric property of Langmuir-films. MDC flowing across monolayers is analyzed using a rod-like molecular model. A linear relationship between the monolayer compression speed and the molecular area Am. Compression speed was about 30, 40, 50mm/min. Langmuir-Blodgett(LB)layers of Arachidic acid deposited by LB method were deposited onto slide glass as Y-type film. The structure of manufactured device is Au/Arachidic acid/Al, the number of accumulated layers are 9~21. Also, we then examined of the Metal-Insulator-Metal(MIM) device by means of I-V. The I-V characteristics of the device are measured from -3 to +3[V]. The insulation property of a thin film is better as the distance between electrodes is larger.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2006.06a
• /
• pp.370-371
• /
• 2006

Maxwell displacement current (MDC) measurement has been employed to study the dielectric property of Langmuir-films. MDC flowing across monolayers is analyzed using a rod-like molecular model. A linear relationship between the monolayer compression speed and the molecular area Am. Compression speed was about 30, 40, 50mm/min. Langmuir-Blodgett(LB)layers of Arachidic acid deposited by LB method were deposited onto slide glass as Y-type film. The structure of manufactured device is Au/Arachidic acid/Al, the number of accumulated layers are 9~21. Also, we then examined of the Metal-Insulator-Metal(MIM) device by means of I-V. The I-V characteristics of the device are measured from -3 to +3[V]. The insulation property of a thin film is better as the distance between electrodes is larger.

• Journal of Sericultural and Entomological Science
• /
• v.24 no.2
• /
• pp.81-84
• /
• 1983

The equilibrium sorption of Orange II by silk fibroin in the range of 50$^{\circ}$, 70$^{\circ}$, 90$^{\circ}C$ and to pH 1.5, 2.2, and 4.0 have been discussed in the light of the dual sorption. Langmuir sorption constant K$\_$L/ and partition coefficient K$\_$P/ were decreased with the increase of the temperature and the pH for the dyeing of silk fibroin with Orange II. Positive values for adsorption entropy were observed. It was found that the values of $\Delta$H$^{\circ}$ is negative for dyeing conditions, and the dyestuff/fibre reaction is therefore exothermic.refore exothermic.

• Korean Chemical Engineering Research
• /
• v.61 no.2
• /
• pp.273-277
• /
• 2023

The biosorption of methylene blue (MB) from aqueous solution was investigated using dried Rhodotorula glutinis as the biosorbent. The effects of pH, initial dye concentration, biosorbent dosage, and kinetic studies were determined to obtain valuable information for biosorption. Results indicated that most of the adsorbed MB bound within 30 minutes of contact and the MB adsorption capacity increased from 21.1 to 101.8 mg/g with the initial MB concentration increased from 50 to 300 mg/L. Additionally, the MB adsorption capacity gradually increased from pH 4.0 to 9.0, reaching its peak at an initial pH of 9.0. As the biomass load was increased from 0.25 to 4.0 g/L, the MB removal efficiency increased from 14.1 to 84.5%. The Langmuir model provided the best fit throughout the concentration range, and the maximum adsorption capacity (q_max) and Langmuir constant (b) were determined to be 135.14 mg/g and 0.026 l/mg, respectively. Furthermore, the biosorbent process of R. glutinis was found to follow pseudo-second-order kinetics and the calculated q_eq,cal value showed good agreement with the experimental q_eq value. Overall, the biosorption of MB by R. glutinis can be characterized as a monolayer, single site type phenomenon, and the rate-limiting step was determined to be the chemical reaction between the adsorbent and the adsorbate.

• Journal of Wetlands Research
• /
• v.26 no.3
• /
• pp.272-278
• /
• 2024

Due to industrialization, a trace amount of residues of pharmaceuticals and personal hygiene products (PPCPs) flows into the ecosystem, polluting the ecosystem. In particular, it was intended to remove trace pollutants flowing into the effluent due to the increase in the amount of acetaminophen detected after COVID 19. To conduct this experiment, selected 6 media which are suitable for construcgted wetland and isothermal adsorption experiments. Langmuir equation and the Freundlich equation were used to calculate the maximum removal rate of acetaminophen. Among them, the Freundlich equation showed a higher result value of 0.9823. It was applied when forming constructed wetlands in urban areas to model the reduction rate of acetaminophen in wetlands.

• Journal of Environmental Science International
• /
• v.24 no.1
• /
• pp.1-7
• /
• 2015

The solid-phase extractant PS-D2EHPA/TBP was prepared by immobilizing two extractants D2EHPA and TBP in polysulfone (PS). The prepared PS-D2EHPA/TBP was characterized by using fourier transform infrared spectrometer (FTIR) and scanning electron microscopy (SEM). The removal of Cu(II) from aqueous solution was investigated in batch system. The experiment data were obeyed the pseudo-second-order kinetic model. Equilibrium data were well fitted by Langmuir model and the removal capacity of Cu(II) by solid extractant PS-D2EHPA/TBP obtained from Langmuir model was 3.11 mg/g at 288 K. The removal capacity of Cu(II) was increased according to increasing pH from 2 to 6, but the removal capacity was decreased below pH 3 remarkably.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.15 no.4
• /
• pp.107-114
• /
• 2007

A study on the removal of heavy metals using alginic acid, a kind of polysaccharides, was performed. Alginic acid adsorbed 480 mg Pb/g dry mass at pH 4, which was about twice as high as uptake capacity of other biosorbents. Isothermal adsorption curve for lead ions was described by the Langmuir model equation and the experimental data well fitted to model equation. The adsorption of lead ions was an endothermic process since binding strength increased with temperature. The effect of alkali metal ions ($Ca^{2+}$ and $Mg^{2+}$) on lead sorption capacity was negligible and most adsorption process was completed in 30min. The uptake capacity of other metals such as, copper, mercury, strontium, and cesium ions using alginic acid was also investigated.

• Journal of Environmental Science International
• /
• v.24 no.7
• /
• pp.841-849
• /
• 2015

The solid phase extractant SAN-D2EHPA/TBP containing two extractants of Di-(2-ethylhexyl)phosphoric acid (D2EHPA) and Tri-butyl-phosphate (TBP) was prepared by immobilizing two exractants D2EHPA and TBP in styrene acrylonitrile copolymer (SAN). The prepared SAN-D2EHPA/TBP was characterized by using fourier transform infrared spectrometer (FTIR) and scanning electron microscopy (SEM). The solid phase extractant SAN-D2EHPA/TBP was tested for the removal of Cu(II) from aqueous solution. Experiments were carried out as a function of the pH and Cu(II) concentration in the aqueous phase. The equilibrium time was 180 min and equilibrium experiment data obeyed the pseudo-second-order kinetic model. The Langmuir isotherm model represented the experiment data as well. The maximum removal capacity of Cu(II) calculated from Langmuir isotherm model was 3.1 mg/g.

• Journal of Environmental Science International
• /
• v.29 no.8
• /
• pp.827-835
• /
• 2020

Zeolite material having XRD peaks of Na-A zeolite in the 2θ range of 7.18 to 34.18 can be synthesized from the waste catalyst using a fusion/hydrothermal method. The adsorption rate of Mn ions by a commercial Na-A zeolite and the synthesized zeolitic material increased as the adsorption temperature increased in the range of 10 ~ 40℃. The adsorption of Mn ion were very rapid in the first 30 min and then reached to the equilibrium state after approximately 60 min. The adsorption kinetics of Mn ions by the commercial Na-A zeolite and the zeolitic material were found to be well fitted to the pseudo-2^nd order kinetic model. Equilibrium data by the commercial Na-A zeolite and the zeolitic material fit the Langmuir, Koble-Corrigan, and Redlich-Peterson isotherm models well rather than Freundlich isotherm model. The removal capacity of the Mn ions by the commercial Na-A zeolite and the zeolitic material obtained from the Langmuir model was 135.2 mg/g and 128.9 mg/g at 30℃, respectively. The adsorption capacity of Mn ions by the synthesized zeolitic material was almost similar to that of commercial Na-A zeolite. The synthesized zeolitic material could be applied as an economically feasible commercial adsorbent.

• Carbon letters
• /
• v.8 no.3
• /
• pp.199-206
• /
• 2007

The activated carbon produced from rubber wood sawdust by chemical activation using phosphoric acid have been utilized as an adsorbent for the removal of Cu(II) from aqueous solution in the concentration range 5-40 mg/l. Adsorption experiments were carried out in a batch process and various experimental parameters such as effect of contact time, initial copper ion concentration, carbon dosage, and pH on percentage removal have been studied. Adsorption results obtained for activated carbon from rubber wood sawdust were compared with the results of commercial activated carbon (CAC). The adsorption on activated carbon samples increased with contact time and attained maximum value at 3 h for CAC and 4 h for PAC. The adsorption results show that the copper uptake increased with increasing pH, the optimum efficiency being attained at pH 6. The precipitation of copper hydroxide occurred when pH of the adsorbate solution was greater than 6. The equilibrium data were fitted using Langmuir and Freundlich adsorption isotherm equation. The kinetics of sorption of the copper ion has been analyzed by two kinetic models, namely, the pseudo first order and pseudo second order kinetic model. The adsorption constants and rate constants for the models have been determined. The process follows pseudo second order kinetics and the results indicated that the Langmuir model gave a better fit to the experimental data than the Freundlich model. It was concluded that activated carbon produced using phosphoric acid has higher adsorption capacity when compared to CAC.