• Korean Journal of Environmental Agriculture
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• v.20 no.3
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• pp.162-168
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• 2001

This study was conducted to evaluate the degradation, adsorption and desorption and leaching of acetamiprid in soils. The half-life of acetamiprid in field condition was $1.7{\sim}3.3$ days in Bokhyun soil and, in case of laboratory condition, 15.5 days. Adsorption of acetamiprid was equilibrated in 12 hours incubation. In adsorption experiment using modified soils, such as oxidized soil, oxidized soil added humic acid, fulvic acid, kaolinite or montmorillinite, adsorption rate of acetamiprid was the highest in the oxidized soil added fulvic acid. The desorption rate was the lowest in the oxidized soil added fulvic acid. The adsorption and desorption results should be suggested that acetamiprid could be strongly adsorbed with soil humic materials, especially fulvic acid. When the mobility of acetamiprid in soil was calculated according to GUS (Groundwater Ubiquity Score) equation, it was prove to non-leacher, and it was confirmed in the leaching experiment with soil column. Most of acetamiprid was remained in the upper 30 cm of the soil column after eluting with water and it was not even detected in leachate.

• Journal of the Korean Wood Science and Technology
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• v.42 no.2
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• pp.207-213
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• 2014

This study was carried out to investigate the feasibility and usefulness of a commercial synthetic adsorbent, Diaion HP 20, for the isolation of proanthocyanidins (PAs) from hot water extract (HWE) prepared from Pinus radiata bark. Most ultraviolet (UV) absorbing materials in HWE were adsorbed onto Diaion HP 20 and easily recovered by simple ethanol (EtOH) washing. More than 50% of the UV absorbing materials were adsorbed within 20 minutes, and the adsorption equilibrium was reached within 3 h. The recovered materials from Diaion HP 20 were mostly composed of PAs, but some monomeric flavonoids such as taxifolin and unidentified hydrophobic materials were also adsorbed. The impurities such as carbohydrates and inorganic materials contained in HWE were mostly removed by Diaion HP 20. The adsorption ability of the UV absorbing materials onto Diaion HP 20 was almost the same as the first cycle even after 14 times of repeating cycles of adsorption and desorption. The radical scavenging ability of the recovered materials from the adsorbent was slightly higher than that of the pure PAs prepared by Sephadex LH 20 from the same HWE.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.219-219
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• 2012

The formation and thermal desorption behaviors of octanethiol (OT) SAMs on single crystalline Au (111) and polycrystalline Au, Ag, and Cu substrates were examined by X-ray photoelectron microscopy (XPS), thermal desorption spectroscopy (TDS), and contact angle (CA) measurements. XPS and CA measurements revealed that the adsorption of octanethiol (OT) molecules on these metals led to the formation of chemisorbed self-assembled monolayers (SAMs). Three main desorption fragments for dioctyl disulfide (C8SSC8+, dimer), octanethiolate (C8S+), and octanethiol (C8SH+) were monitored using TDS to understand the effects of surface morphology and the nature of metal substrates on the thermal desorption behavior of alkanethiols. TDS measurements showed that a sharp dimer peak with a very strong intensity on single crystalline Au (111) surface was dominantly observed at 370 K, whereas a broad peak on the polycrystalline Au surface was observed at 405 K. On the other hand, desorption behaviors of octanethiolates and octanethiols were quite similar. We concluded that substrate morphology strongly affects the dimerization process of alkanethiolates on Au surfaces. We also found that desorption intensity of the dimer is in the order of Au＞＞Ag＞Cu, suggesting that the dimerization process occurs efficiently when the sulfur-metal bond has a more covalent character (Au) rather than an ionic character (Ag and Cu).

• Journal of the Korean Chemical Society
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• v.54 no.5
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• pp.533-540
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• 2010

An activated carbon was tested for its ability to remove transition metal ions from aqueous solutions. Physical, chemical and liquid-phase adsorption characterizations of the carbon were done following standard procedures. Studies on the removal of Ni(II), Cu(II) and Fe(III) ions were attempted by varying adsorbate dose, pH of the metal ion solution and time in batch mode. The equilibrium adsorption data were fitted with Freundlich and Langmuir and the isotherm constants were evaluated, equilibrium time of the different three metal ions were determined. pH was found to have a significant role to play in the adsorption. The processes were endothermic and the thermodynamic parameters were evaluated. Desorption studies indicate that ion-exchange mechanism is operating.

• Applied Biological Chemistry
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• v.40 no.2
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• pp.128-133
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• 1997

This study was conducted to evaluate the adsorption, desorption, leaching and degradation pattern of fungicide fluazinam in the soil environment under the laboratory conditions. The mode of isothermal adsorption of fluazinam in soil was coincident with the Freundlich equation. The adsorption amount of fluazinam was much higher on soils containing organic matter than on soils oxidized with hydrogen peroxide. The presence of organic matter, humic acid or fulvic acid, increased the adsorption amount of fluazinam on soils. The Freundlich constant K was much higher in soil added with humic acid than in soil added with fulvic acid. The desorption ratio of fluazinam adsorbed to soil was increased by removal of organic matter. In leaching experiment using soil column, the fluazinam applied on the soil surface was not moved down to the bottom of soil and was not detected in leachate water. The degradation of fluazinam was faster in Soil I with rich organic matter than Soil II with poor organic matter, in non-sterilized soil than sterilized soil, and in flooded soil than unflooded soil.

• KIEAE Journal
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• v.12 no.5
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• pp.71-76
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• 2012

As reviewed of developments of Korean earth architecture, earth-made buildings have been dwindled gradually since "the new community movement" and earth have been recognized as materials which are not so good to human health and in result, earth-related techniques have been also forgotten. However, recently the earth architecture has been more attracting back many attentions thanks to the people who are interested in health and wellbeing and the earth related techniques or skills got keenly required. The present study has investigated and reproduced earth finishing materials which are based on natural materials as basic stuffs to use them as the finishing materials of the modern earth architecture. For the test, the finishing materials have been divided roughly into sorts of pastes and oils. In case of applying finishing materials onto earth surfaces, the moisture permeability test was conducted to measure a water-absorbing speed, and at the case of using finishing materials for interior works moisture adsorption/desorption test was performed to verify the indoor humidity regulation ability, and further a test to check whether to be stained when contacted with the finishing materials, was conducted. If there is not any stain it might be recognized to be high quality of moisture adsorption/desorption and so seaweed pastes or starches might be used for paste finishing materials and for natural oils, beans are desirable in practical ways. As low-quantity of moisture adsorption materials, linseed oil is most desirable and also beaned water over75% are thought to be useful.

• Resources Recycling
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• v.32 no.6
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• pp.45-53
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• 2023

This study discussed the trend and future strategy of adsorption technology R&D to effectively recover ammonia emitted from the livestock fields. A proper ammonia adsorbent should incorporate acidic or hydrogen bonding functional groups on the surface, as well as a high specific surface area and a good surface structure appropriate for ammonia adsorption. Activated carbon and minerals such as zeolite have widely been used as ammonia adsorbents, but their adsorption effects are generally low, so any improvement through surface modification should be necessary. For example, incorporation of metal chloride included in a porous adsorbent can promote ammonia adsorption effectiveness. Recently, new types of adsorbents such as MOFs (Metal-Organic Frameworks) and POPs (Porous Organic Polymers) have been developed and utilized. They have shown very high ammonia adsorption capacity because of adjustable and high specific surface area and porosity. In addition, Prussian Blue exhibited high ammonia adsorption and desorption performance and selectivity. This looks relatively advantageous in relation to the recovery of ammonia from livestock waste discharge. In the future, further research should be made to evaluate ammonia adsorption/desorption efficiency and purity using various adsorbents under conditions suitable for livestock sites. Also, effective pre- and/or post-treatment processes should be integrated to maximize ammonia recovery.

• Membrane and Water Treatment
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• v.7 no.1
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• pp.55-70
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• 2016

Microfiltration/ultrafiltration (MF/UF) Adsorptive polyamide-6 (PA-6) membranes were prepared using wet phase inversion process. The prepared PA-6 membranes are characterized by scanning electron microscopy (SEM), porosity and swelling degree. In this study, the membranes performance has examined by adsorptive removal of copper ions from aqueous solutions in a batch adsorption mode. The $PA-6/H_2O$ membranes display sponge like and highly porous structures, with porosities of 41-73%. Under the conditions examined, the adsorption experiments have showed that the $PA-6/H_2O$ membranes had a good adsorption capacity (up to 120-280 mg/g at the initial copper ion concentration ($C_0$) = 680 mg/L, pH7), fast adsorption rates and short adsorption equilibrium times (less than 1.5-2 hrs) for copper ions. The fast adsorption in this study may be attributed to the high porosities and large pore sizes of the $PA-6/H_2O$ membranes, which have facilitated the transport of copper ions to the adsorption. The results obtained from the study illustrated that the copper ions which have adsorbed on the polyamide membranes can be effectively desorbed in an Ethylene dinitrilotetra acetic acid Di sodium salt ($Na_2$ EDTA) solution from initial concentration (up to 92% desorption efficiency) and the PA-6 membranes can be reused almost without loss of the adsorption capacity for copper ions. The results obtained from the study suggested that the $PA-6/H_2O$ membranes can be effectively applied for the adsorptive removal of copper ions from aqueous solutions.

• Journal of the Korean Electrochemical Society
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• v.3 no.2
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• pp.104-108
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• 2000

It is very important to know the real roughness of electrode surface in electrochemistry. But it is impossible to know absolute roughness of electrode surface for various reasons. In this work, we compared the roughnesses of polycrystalline gold electrode often used in electrochemistry calculated from the images of scanning tunneling microscopy (STM) and cyclic voltammetry with those of Au (111) and HOPG. The roughness of polycrystalline gold calculated from STM image was $1.1(\pm0.1)$, that from adsorption-desorption of oxygen was $2.4(\pm0.7)$ and that from adsorption of N-docosyl-N'-methyl viologen was $1.6(\pm0.1)$.

• Applied Chemistry for Engineering
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• v.20 no.2
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• pp.117-125
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• 2009

In order to utilize natural gas (NG), one of the clean energy sources in next-generation, as a fuel for vehicles, it is important to store natural gas with high density. To store NG by adsorption (ANG) at room temperature and at relatively low pressure(35~40 atm) is safe and economical compared with compressed NG and liquefied NG. However, so far no adsorbent is reported to have adsorption capacity suitable for commercial applications. Nanoporous materials including metal-organic frameworks can be potential adsorbents for ANG. In this review, physicochemical properties of adsorbents necessary for high adsorption capacity are summarized. Wide surface area, large micropore volume, suitable pore size and high density are necessary for high energy density. Moreover, low adsorption-desorption energy, rapid adsorption-desorption kinetics and high delivery are needed. Recently, various efforts have been reported to utilize nanoporous materials in ANG, and it is expected to develop a nanoporous material suitable for ANG.