• Korean Chemical Engineering Research
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• v.53 no.5
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• pp.576-583
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• 2015

This paper aims to investigate the potential use of cempedak durian peel (CDP) from Negara Brunei Darussalam, which is low-cost, locally available, eco-friendly and highly efficient to remove methyl violet (MV) dye from aqueous solutions. The time required for equilibrium to be reached is 2.0 h with no adjustment of pH necessary. FTIR analysis was indicative of the involvement of -COOH and C=O functional groups in adsorption process. The Langmuir model provided the best fit with maximum adsorption capacity of $0.606mmol\;g^{-1}$. Thermodynamics data indicate that the adsorption is spontaneous, feasible and endothermic in nature. Best regeneration of CDP's adsorption ability is achieved by base solution, showing about 95% removal efficiency of MV even after 5 cycles, indicating that CDP can be regenerated and reused. This, together with its high adsorption capacity, makes CDP a potential adsorbent for the removal of MV in wastewater.

• KSBB Journal
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• v.14 no.1
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• pp.66-70
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• 1999

Comparison of lead removal characteristics between two strains, Aureobasidium pullulans and Saccharomyces cerevisiae, and effects of extracellular polymeric substances(EPS) excreted by microorganisms on the removal of lead were investigated. The capacity of lead biosorption to A. pullulans which had EPS was increased as the storage time of the cells increased, due to the increased amounts of excreted EPS. When the EPS were removed from A. pullulans cells, the amounts of adsorbed lead were very small(10% of the cell with EPS). In the case of s. cerevisiae which had no EPS, the lead removal capacity was nearly constant with storage time except early stage, but the spending time to reach an equilibrium state decreased with increasing storage time because of lowering the function of cell membrane. Therefore, it seems that the phenomena of lead biosorption were remarkably affected by the presence of extracellular polymeric substances.

• Applied Chemistry for Engineering
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• v.18 no.5
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• pp.459-466
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• 2007

In this study, H-type beta zeolites (BEA) having various metals were used as the adsorbent for the removal of sulfur containing odorants. The different adsorbents containing single or bimetals were utilized to investigate the performance in the individual adsorption of TBM and THT odorants or in the competitive adsorption between them by using a continuous adsorptive bed system. The result shows that the pure H-type BEA zeolite exhibited the highest adsorption capacity for TBM compound, but the higher amount of THT was removed and adsorbed on a HBEA adsorbent having Fe, Pd metal and ZnO oxide. In the case of bimetal containing adsorbents, Cu-Zn/HBEA and Fe-Mo/HBEA showed a higher adsorption capacity for TBM.

• Journal of the Korean Society of Safety
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• v.19 no.3 s.67
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• pp.57-64
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• 2004

This is the study for the removal of a toxic heavy metal ions and the recycling of expanded polystyrene wastes. Thus expanded polystyrene wastes collected from the packing materials of TV or chemicals and dissolved by $80wt.\%$ solvent(N, N-Dimethylacrylamide), electrospun in DC 20kV by power supply. Generally, the electrospinning is a process of manufacture to the fibers of nanosize from polymer solution. Manufactured nanofiber mats by electrospinning were sulfonated by cone.-sulphuric acid with $Ag_2S_O_4$ catalysts for the exchange capacity of heavy metal ions and the properties of structure with sulfonated time investigated by FESEM(Feild Emission Scaning Electron Microscope). The ion exchange capacity of light metal$(Na^+)$, Cd(II) and Ni(II), and by a nanofiber mats were 1.94[mmo1/g-dry-mat), 1.72(mmol/g-dry-mat), 1.24(mmol/g-dry-mat), respectively., and water uptake content showed a similar trend with IEC. and The selectivity coefficients $K^M_H$ of Cd(II), Ni((II) ions showed 0.324, 0.228. respectively.

• Earthquakes and Structures
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• v.9 no.3
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• pp.639-656
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• 2015

Seismic isolation devices are commonly used to mitigate damages caused by seismic responses of structures. More damages are created due to progressive collapse in structures. Therefore, evaluating the impact of the isolation systems to enhance progressive collapse-resisting capacity is very important. In this study, the effect of lead rubber bearing isolation system to increase the resistance of structures against progressive collapse was evaluated. Concrete moment resisting frames were used in both the fixed and base-isolated model structures. Then, progressive collapse-resisting capacity of frames was investigated using the push down nonlinear static analysis under gravity loads that specified in GSA guideline. Nonlinear dynamic analysis was performed to consider dynamic effects column removal under earthquake. The results of the push down analysis are highly dependent on location of removal column and floor number of buildings. Also, seismic isolation system does not play an effective role in increasing the progressive collapse-resisting capacities of structures under gravity loads. Base isolation helps to localize failures and prevented from spreading it to intact span under seismic loads.

• Journal of Korean Society on Water Environment
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• v.27 no.4
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• pp.516-522
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• 2011

This study was performed to investigate the removal characteristics of phosphate by adsorption on olivine, which is generated as industrial by-products from quarry. The adsorption of phosphate on olivine was significantly achieved within 1 hour and equilibrated after 3 hours. The adsorption capacity of phosphate was enhanced with decreasing pH. The maximum adsorption capacity was observed to be 0.463 mg/g in the condition of pH 3. The $Ca^{2+}$ and $Mg^{2+}$ ion amount per adsorbent eluted from olivine was increased with decreasing pH. The precipitation test showed that phosphate in aqueous phase under the condition of pH 3 ~ 9 could be eliminated largely by adsorption on olivine, not precipitation. Freundlich adsorption model were successfully applied to describe the adsorption behavior of phosphate on olivine. The $q_m$ of Langmuir adsorption model were 1.3369 mg/g, 1.0544 mg/g, 1.0288 mg/g at pH 3, 6 and 9, respectively. The $K_F$ of Freundlich adsorption model were 0.4247 mg/g, 0.3399 mg/g, 0.2942 mg/g at pH 3, 6 and 9, respectively. The olivine showed high feasibility as a adsorbent for the removal of $PO_4$-P.

• Journal of Soil and Groundwater Environment
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• v.12 no.2
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• pp.37-46
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• 2007

This study developed composition-plastic media with woodchips and plastic as main materials, and examined the performance of media. Compared to the existing commercial media, the media had similar performance in removal efficiency and microbes attaching characteristic, and was evaluated that they are distinguished from economic side. Performance test of media was conducted to examine the removal capacity of toluene and hydrogen sulfide in a gas stream by using a lab-scale biotrickling filter systems packed with them. At a volumetric loading of $1.5\;m^3/hr$ with inlet concentration 260 ppm and empty bed residence time (EBRT) 42s, the toluene removal efficiency was shown over 90%, and the maximum elimination capacity of toluene in the biotrickling filter was $77g/m^3{\cdot}hr$. Effective co-treatments of $H_2S$ and Toluene were observed in the lab-scale biotrickling filters. The maximum elimination capacity of $H_2S$ was $100\;g-S/m^3{\cdot}hr$. Up to 100 ppm, the concentration of $H_2S$ did not have an effect on toluene removal efficiency, but the removal efficiency of toluene decreased with increasing inlet $H_2S$ concentration.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.12
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• pp.1218-1224
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• 2008

A liquid culture of yeast "Candida tropicalis" was used in a fluidized bioreactor to achieve high removal efficiencies of volatile organic compounds (VOCs). In this study, granular activated carbon (GAC) was used as a fluidized material to improve adsorptive capacity as well as mass transfer of gaseous toluene, the model VOC. The GAC fluidized bioreactor demonstrated toluene removal efficiencies ranging from 50 to 80%, when inlet toluene loading varied in a range between 13.1 and 37.4 g/m$^3$-hr. The maximum elimination capacity determined in the GAC fluidized bioreactor was 172 g/m$^3$-hr at a toluene loading of 291 g/m$^3$-hr. Transient loading experiments revealed that the removal efficiency was remained unchanged during an increased loading period, and toluene introduced to the bioreactor was first absorbed to GAC and then slowly desorbed and became available to the yeast culture. Hence the fluidized GAC helped to achieve an improved mass transfer between the gas and liquid phases, resulting in high toluene removal capacity. Consequently, the GAC fluidized bioreactor using C. tropicalis can be successfully applied for the removal of VOCs, and is a feasible alternative over conventional processes such as packed-bed biofilters.

• Journal of environmental and Sanitary engineering
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• v.13 no.2
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• pp.156-164
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• 1998

This study was performed to select media for the development of biological activated carbon process. Using activated carbon made by Norit, Calgon, Samchully Co., removal efficiency of humic acid by the isothermal adsorption test and biodegradation of organic matters by microbes attached to BAC and observation and counting of microbes attached to BAC were examined. The removal efficiency of humic acid with dose of activated carbon was influenced by initial concentration. Compared with other activated carbon, Norit was found to be most effective in view of adsorption capacity, biodegradation of organic matter, and attachment characteristics of microorganism. In conclusion, Norit which has high adsorption capacity and good biodegradation of organic matter was recommended for selecting media in BAC process.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.04a
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• pp.15-18
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• 2001

Sorption/desorption studies were conducted to determine sorption/desorption characteristics of phenolic compounds (phenol and 4-chlorophenol) in organically modified natural bentonite. The cationic exchange capacity (CEC) of bentonite was exchanged with a cationic surfactant, hexadecyltrimethylammonium (HDTMA), to enhance the removal capacity of organic phenol contaminants dissolved in aqueous solution. This modification produces a change of the surface property of bentonite from hydrophilic to organophilic. The single-solute and bi-solute competitive adsorptions were performed In batch mode to investigate the removal of two toxic organic Phenols, chlorophenol and 4-chlorophenol on the HDTMA-bentonite. The adsorption affinity of the 4-chlorophenol was higher than phenol due to higher octanol:water partition coefficient (Kow). The single-solute and bi-solute competitive desorptions were also performed investigate the competitive desorption of the phenolic compounds from HDTMA-bentonite. Freundlich model was used to analyze the single-solute adsorption/desorption results, while the IAST model predicted the hi-solute adsorption/desorption equilibria. The IAST model well predicted hi-solute competitive adsorption/desorption behaviors.