• Journal of the Korean Society of Safety
• /
• v.11 no.1
• /
• pp.84-89
• /
• 1996

The adsorption characteristics of active carbon used as a cartridge filler of organic vapor respirator were examined by humidity, particle size, challenge concentration and specific surface area. As a result, the 1% breakthrough time of Carbon Tetrachloride($CCl_4$) was decreased with increase of relative humidity, challenge concentration and particle size (0.6～2.0mm) of active carbon. The adsorbed amount of $CCl_4$ was about 1. 1mg/$m^2$ at RH 40% and 0. 5mg/$m^2$ at RH 80% . However in the case of prehumidified active carbon, humidity did not affected to 1% breakthrough time up to RH 40%.

• Journal of Korean Society of Water and Wastewater
• /
• v.28 no.4
• /
• pp.453-459
• /
• 2014

The excessive concentration of phosphorus in the river and reservoir is a deteriorating factor for the eutrophication. The converter slag was used to remove the phosphate from the synthetic wastewater. Influencing factors were studied to remove soluble orthophosphate with the different particle sizes through the batch and the column experiments by continuous flow. Freundlich and Langmuir adsorption isotherm constants were obtained from batch experiments with $PS_A$ and $PS_B$. Freundlich isotherm was fitted better than Langmuir isotherm. Regression coefficient of Freundlich isotherm was 0.95 for $PS_A$ and 0.92 for $PS_B$, respectively. The adsorption kinetics from the batch experiment were revealed that bigger size of convert slag, $PS_A$ can be applied for the higher than 3.5 mg/L of phosphate concentration. The pilot plant of continuous flow was applied in order to evaluate the pH variation, breakthrough points and breakthrough adsorption capacity of phosphate. The variation of pH was decreased through the experimental hours. The breakthrough time was 1,432 and 312 hours to 10 mg/L and 50 mg/L for the influent concentration, respectively. The breakthrough adsorption capacity was 3.54 g/kg for 10 mg/L, and 1.72 g/kg for 50 mg/L as influent phosphate concentration.

• Journal of Microbiology and Biotechnology
• /
• v.11 no.5
• /
• pp.776-780
• /
• 2001

Based on the static and dynamic adsorption of Streamline DEAE, a modified tank-in-series model including particle size distribution was used to describe the adsorption performance of bovine serum albumin in an expanded bed. The calculated results indicated that the suggested model was able to simulate breakthrough curves under various conditions.

• Proceedings of the Korean Environmental Health Society Conference
• /
• 2005.06a
• /
• pp.381-385
• /
• 2005

Characterization of particle behavior is becoming more important in performance evaluation of water treatment system as well as in operation of the system because conventional parameter, turbidity has lack of explaining ability on small sized microorganisms such like Cryptosporidium etc. Accordingly, particle counter has been introduced in evaluation and operation of the treatment system. However researches on the relationship between turbidity, particle count and/or different sand/anthracite sizes have not been concurrent. Therefore in this study, the relationship was investigated to improve performance evaluation of sand filter so as to help choosing sand/anthracite effective size as a design parameter of water treatment facility. According to the results, too small or too large effective size media filter reached to turbidity limit(0.1 NTU)earlier. However, because shallow sand layer may cause early breakthrough, the depth of sand layer should be provided enough in order to compromise water quality and productivity.

• Journal of Environmental Science International
• /
• v.14 no.1
• /
• pp.61-69
• /
• 2005

Adsorption characteristics of toluene vapor, which is one of important source of volatile organic compounds (VOCs), by activated carbon were investigated using a fixed bed adsorption column. The operating parameters such as breakthrough curve, adsorption capacity, mass transfer zone (MTZ), and length of unused bed (LUB) were studied. The experimental results showed that the breakthrough time decreased with increasing inlet toluene concentration and gas flow rate. MTZ and LUB increased with the increase of inlet concentration, gas flow rate, and particle size of activated carbon. The adsorption capacity increased with the increase of inlet toluene concentration, while it decreased with increasing particle size. However, it was kept at constant value regardless of the increase of gas flow rate. Adsorption isotherm of toluene vapor could be represented by the Freundlich adsorption equation fairly well. From the adsorption experiments using some VOC gases such as toluene, xylene, butyl acetate. butanol and acetone, it was also found that the adsorption capacity was higher in the case of gas with higher boiling point and lower vapor pressure.

• Resources Recycling
• /
• v.9 no.1
• /
• pp.70-75
• /
• 2000

The sand particle was coated with $Fe_3O_4$ and then $Fe_2O_3$ that adsorption capacity was more excellent than $Fe_3O_4$ was mostly found in 2nd step for preparation of iron-oxide-coated sand (IOCS). The copper removal rate was 74.9 percent by adding 30 gram per liter iron-oxide-coated sand from the solution with 5 mg/l Cu in 20 minute. Breakthrough time occurred in 23 hours and adsorption capacity 0.87$\cdot$Cu/g$\cdot$IOCS in case of breakthrough copper concentration was 1.0 mg/l in the continuous test.

• Nuclear Engineering and Technology
• /
• v.44 no.1
• /
• pp.79-88
• /
• 2012

Migration tests were performed with conservative tracers in a fractured zone that had a single fracture of about 2.5 m distance at the KURT. To interpret the migration of the tracers in the fractured rock, a solute transport model was developed. A two dimensional variable aperture channel model was adopted to describe the fractured path and hydrology, and a particle tracking method was used for solute transport. The simulation tried not only to develop a migration model of solutes for open flow environments but also to produce ideas for a better understanding of solute behaviours in indefinable fracture zones by comparing them to experimental results. The results of our simulations and experiments are described as elution and breakthrough curves, and are quantified by momentum analysis. The main retardation mechanism of nonsorbing tracers, including matrixdiffusion, was investigated.

• Journal of Environmental Health Sciences
• /
• v.19 no.4
• /
• pp.25-32
• /
• 1993

Granular activated carbon is commonly used in fixed-bed adsorbers to remove organic chemicals. In this experiment organic chemical solutions were prepared by adding the reagent grade organic chemical to distilled water. Isotherm adsorption tests of volatile organic chemicals were conducted using bottle-point technique and column test. Organic chemicals after passing through the column were extracted with hexane and analyzed with gas chromatography (Hewlett-Packard 5890) to check the adsorption capacity and breakthrough curve. The result were as follows: 1. The BET surface area of coconut activated carbon was 658~1,010 m$^2$/g where as coconut shell carbon was 6.6 m$^2$/g. Coconut activated carbon increased the BET surface area and adsorption capacity in bottle-point isotherm. 2. The adsorption capacity of coconut activated carbon for trichloroethylene (TCE) was reduced in the presence of humic substance. 3. A decrease in particle size of activated carbon resulted in higher adsorption capacity and lower intraparticle diffusion coefficient. It is reflected not only as a decrease in Freudlich adsorption capacity value (K) but also as an increase in Freudlich exponenent value (1/n).

• Journal of Korean Society of Environmental Engineers
• /
• v.22 no.2
• /
• pp.217-229
• /
• 2000

Adsorption equilibrium experiments for the phenol on granular activated carbon(16~25 mesh) and powder activated carbon(325 mesh) were carried out at $25{\pm}1^{\circ}C$ and the results were expressed with Freundlich isotherm. Adsorption rate experiments were executed in batch adsorption system under the condition that can be neglecting mass transfer resistance at the external surface of the particle. The results were analysed with the Miller's method to evaluate the linear driving force(LDF) adsorption rate constant. Fixed bed adsorption experiments were performed by adopting different flow rates in the activated carbon-phenol system at $25{\pm}1^{\circ}C$. The theoretical breakthrough curves were estimated with the simple constant pattern solution. The adsorption rate constant of LDF model was not a fixed value but variable with adsorption amount. The experimental results were better agreed with the estimation of breakthrough curve using the variable adsorption rate constant than the results estimated using the average fixed adsorption rate constant.

• Journal of Korean Society of Environmental Engineers
• /
• v.32 no.10
• /
• pp.936-941
• /
• 2010

This study was conducted to investigate formaldehyde removals by silver nano-particles attached on the surface of granular activated carbon (Ag-AC) and to compare the results to those obtained with ordinary activated carbon (AC). The BET analysis showed that the overall surface area and the fraction of micropores (less than $20{\AA}$ diameter) of the Ag-AC were significantly decreased because the silver particles blocked the small pores on the surface of the Ag-AC. The formaldehyde removal capacity of the Ag-AC determined using the Freundlich isotherm was higher than that of AC. Despite the decreased BET surface area and micropore volume, the Ag-AC had the increased removal capacity for formaldehyde, presumably due to catalytic oxidation by silver nano-particles. In contrast, the adsorption intensity of the Ag-AC, estimated by 1/n in the Freundlich isotherm equation, was similar to that of the ordinary AC, indicating that the surface modification using silver nano-particles did not affect the adsorption characteristics of AC. In a column experiment, the Ag-AC also showed a longer breakthrough time than that of the AC. Simulation results using the homogeneous surface diffusion model (HSDM) were well fitted to the breakthrough curve of formaldehyde for the ordinary AC, but the predictions showed substantial deviations from the experimental data for the Ag-AC. The discrepancy was due to the catalytic oxidation of silver nano-particles that was not incorporated in the HSDM. Consequently, a new numerical model that takes the catalytic oxidation into accounts needs to be developed to predict the combined oxidation and adsorption process more accurately.