• Journal of Korean Society of Environmental Engineers
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• v.31 no.10
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• pp.909-918
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• 2009

As a part of dissolved organic matter, dissolved organic carbon (DOC) or biodegradable DOC (BDOC) fraction in particular is one of important issues in water treatment. Due to role as a nutrient source for bacteria, BDOC, therefore, may cause regrowth problems in water distribution system. The main objectives of this study were to investigate the possibility to minimize the concentration of BDOC in advance water treatment process. DOC in water is fractionized into four fractions such as AnBDOC (adsorbable and non-biodegradable DOC) which possesses adsorption properties but no biodegradation ability; nABDOC (biodegradable and non-adsorbable DOC) which has biodegradation properties but no adsorption ability; ABDOC (adsorbable and biodegradable DOC) which has adsorption properties and biodegradable characteristic; and non-removal DOC (nAnBDOC) which do not have either adsorbability or biodegradability. BAC process was effective for adsorbable DOC (AnBDOC+ABDOC) removal. However, in some cases, the removal ratio of adsorbable DOC was not sufficient. BDOC removal rate is very low or irremovable. Thus, for the control of residual DOC, it is necessary to change the operation condition by BAC process. From the analysis results of DOC fractions, water treatment processes appeared to be effective because it could grasp a remarkable amount of biodegradable, adsorbable and non-removal DOC. The concentration of AOX in non-prechlorination process was reduced from 7.1 ${\mu}g$/L to 0.51 ${\mu}g$/L in BAC process followed by ozonation.

• Korean Journal of Soil Science and Fertilizer
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• v.35 no.6
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• pp.344-351
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• 2002

Chemical speciation and transport of heavy metals in soil environment could be controlled by humic acid. In order to understand the mechanism on competitive adsorption of Cd and Cu on the surface of humic acid extracted from peat, the charge development of humic acid were investigate through a batch adsorption experiment with a series of different background electrolytes levels. The competitive adsorption of Cd and Cu to the humic acid were estimated according to the model using the proton binding constant obtained from the above batch test. The affinity of Cu to the carboxyl group on the humic acid was higher than that of Cd, but the affinity to the phenolic group was lower than to the carboxyl group. It seems that the amount of adsorbed Cd and Cu could be estimated using the proton binding constant obtained from a solution with single background ion. However, it is difficult to interpret the competitive adsorption of Cd and Cu with the constant for single background ion.

• Korean Journal of Environmental Biology
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• v.41 no.4
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• pp.370-385
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• 2023

Cyanobacterial harmful algal blooms (Cyano-HABs) are an international environmental problem that negatively affects the ecosystem as well as the safety of water resources by discharging cyanotoxins. In particular, the discharge of microcystins (MCs), a highly toxic substance, has been studied most actively, and various water treatment methods have been proposed for this purpose. In this paper, we reviewed adsorption technology, which is recognized as the most feasible, economical, and efficient method among suggested treatment methods for removing MCs. Activated carbons (AC) are widely used adsorbents for MCs removal, and excellent MCs adsorption performance has been reported. Research on alternative adsorption materials for AC such as biochar and biosorbents has been conducted, however, their performance was lower compared to activated carbon. The impacts of adsorbent properties(characteristics of pore surface chemistry) and environmental factors (solution pH, temperature, natural organic matter, and ionic strength) on the MCs adsorption performance were also discussed. In addition, toward effective control of MCs, the possibility of the direct removal of harmful cyanobacteria as well as the removal of dissolved MCs using adsorption strategy was examined. However, to fully utilize the adsorption for the removal of MCs, the application and optimization under actual environmental conditions are still required, thereby meeting the environmental and economic standards. From this study, crucial insights could be provided for the development and selection of effective adsorbent and subsequent adsorption processes for the removal of MCs from water resources.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.5
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• pp.827-835
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• 2000

Adsorption characteristics of uranium on activated carbon whose surface is modified with $HNO_3$ and/or NaOH were investigated. Na-OAC, which was the activated carbon treated with both $HNO_3$ and NaOH. showed higher adsorption capacity than OAC, which was treated with $HNO_3$, as well as Na-AC, which was treated with only NaOH. This can be explained based on the surface functional groups increased by surface modification of activated carbon and the change of solution pH as adsorption proceeds. From these experimental results, it is thought that the pH of uranium solution and surface functional groups on the activated carbon surface are the governing factors in the uranium adsorption system.

• Polymer(Korea)
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• v.25 no.5
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• pp.642-648
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• 2001

An attempt was made to synthesize an ammonia adsorbent by the photo-induced grafting of styrene (St) onto polypropylene (PP) nonwoven using benzoin ethyl ether (BEE) as a photosensitizer with urea and trimethylol propane triacrylate in methanol medium. As styrene concentration was increased, the graft yield was increased. It was also found that the graft yield increased with reaction time. The polypropylene grafted with styrene (PP-g-St) was sulfonated by chlorosulfonic acid in dichloroethane and complexed with several metal ion, such as $cO^{+2}$, $nI^{+2}$, $cU^{+2}$, $Zn^{+2}$. The amount of ammonia gas adsorbed by these sample was dependent on the degree of sulfonation, adsorption time, and ammonia gas pressure. The adsorption capacity of ammonia gas by the sulfonated PP-g-St(SPP-g-St) nonwoven with 4. 25 mmol $H^+$/g was 6.61 mmol/g. Metal ion complexed SPP-g-St nonwovens had higher adsorption capacity than SPP-g-St nonwoven and the $Co^{+2}$ complexed SPP-g-St showed 9.90 mmol $NH_3$/g, which was much higher than that of active carbon or silica gel.

• Journal of the Korean Vacuum Society
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• v.15 no.4
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• pp.360-366
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• 2006

We have performed density functional theory calculations for the surface structure of O/Pd(100)-p($2{\times}2$), formed by the adsorption of oxygen atoms of 0.25 ML. The oxygen atoms adsorb preferentially at the fourfold hollow site, and the calculated O-Pd bond length is $2,15{\AA}$, The first interlayer spacing ($d_{12}$) of Pd(100) expands by +0.8% due to the oxygen adsorption, which differs from the experimental value of +3.6% reported by a previous LEED study. Assuming that the LEED sample was possibly contaminated by hydrogen atoms, we also examined the effect of hydrogen impurities on the surface structure. Hydrogen atoms adsorbed on O/Pd(100)-p($2{\times}2$) are found to result in large expansions of $d_{12}$ of Pd(100). Our analysis estimates the amount of hydrogen atoms remaining on the LEED sample as -0.3 ML.

• Economic and Environmental Geology
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• v.38 no.5 s.174
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• pp.525-534
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• 2005

Adsorption experiments for As(V) and As(III) onto the surfaces of aerobic Pseudomonas aeruginosa, which can be readily isolated from natural media, were conducted under nutrient-absent conditions. While a small amount of As(III) was adsorbed on the bacterial cell surfaces, As(V) was not effectively removed from the solution through adsorption. The result was likely due to the electrostatic repulsion between anionic compounds of aqueous As(V) and cell surfaces of f aeruginosa. However, the bacteria forming biofilm reduced a large amount of aqueous As(V) to As(III), which indicated that microorganisms in most oligotrophic, natural geologic settings can mediate the behavior of aqueous As. Biobarriers designed to remove the various heavy metals in contaminant plume may practically lead to the enhancement of toxicity and mobility of As.

• Journal of the Korean Chemical Society
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• v.61 no.6
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• pp.352-358
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• 2017

The addition of alginic acid, a natural polysaccharide, to improve the wettability and the reduction of protein adsorption of hydrogel contact lenses. Hydrogel contact lenses were manufactured with various monomers such as 2-methacryloyloxyethyl phosphorylcholine (MPC) and NVP (N-Vinyl-2-pyrrolidone). Alginic acid was added by by the initial mixing method and the interpenetrating polymer networks(IPN) method. Properties of contact lens such as contact angle, oxygen permeability, and protein adsorption amount were evaluated. The oxygen permeability and wettability of the IPN-treated alginate samples were higher than those of the samples that were not treated with IPN. The physical properties were improved as the concentration of IPN-treated alginic acid increased. Protein adsorption decreased by the addition of alginic acid and further decreased with IPN. In particular, contact lenses containing MPC and NVP significantly decreased protein adsorption. Therefore, the effect of alginate on the functional improvement of contact lens was confirmed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.7 no.2
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• pp.37-44
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• 1987

Adsorption characteristics of chloroform, carbon tetrachloride, and crystal violet were investigated in single-and bi-solute systems. Single-solute adsorption for each solute was well described by Freundlich equation. Severe inhibition was recorded in bi-solute adsorption systems despite of low solute concentration of less than 1 mg/l. Inhibition of chloroform adsorption by carbon tetrachloride, similar compound in chemical structure, was much higher than by crystal violet of which chemical structure is quite different. Highest inhibition was observed at crystal violet adsorption by chloroform. While, inhibition caused by each other was almost equal between chloroform and carbon tetrachloride. Bi-solute adsorption was well described by Friz-Schl${\ddot{u}}$nder model and by much simpler 3 parameter Freundlich equation.

• Korean Journal of Environmental Agriculture
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• v.19 no.3
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• pp.191-193
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• 2000

To find out the countermeasure to plant damage at soil contaminated with oil, several adsorbents such as muck, peat, sawdust and PEAT SORB were treated at diesel oil contaminated soil. As the results, sawdust and PEAT SORB showed better effect of oil adsorption than muck and peat. Removal rate of diesel oil with sawdust treatment was higher than 95% at the condition which the ratio of adsorbent amount to oil was higher than 1:2(w/v). And the releasing amount of oil from adsorbent-oil complex was very small. With the oil treatment of $4,000\;L{\cdot}ha^{-1}$ at tillering stage, rice plant height and chlorophyll content were lower than control at non-adsorbent treatment, but those were increased at sawdust treatment.