• Applied Chemistry for Engineering
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• v.17 no.3
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• pp.280-285
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• 2006

Adsorption characteristics of $H_{2}S$ on KOH impregnated activated carbon were evaluated using dynamic adsorption method in a fixed bed. The pore properties, including BET's specific surface area, pore volume, pore size distribution, and mean pore diameter of these KOH impregnated activated carbons, were characterized from $N_{2}$ adsorption/desorption isotherms. Adsorption equilibrium data were correlated with Langmuir and Freundlich isotherms. The adsorption of $H_{2}S$ onto the KOH impregnated activated carbon is better fitted by the Langmuir isotherm. An increase in the content of oxygen affects the performance of KOH impregnated activated carbon to the greatest extent.

• Analytical Science and Technology
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• v.20 no.1
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• pp.1-9
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• 2007

The BOD (biochemical oxygen demand) sensor was fabricated by covering a dissolved oxygen (DO) probe with a microbe-impregnated membrane and a dialysis membrane. Various microorganisms isolated from the soils, water and activated sludge have been evaluated for measuring biochemical oxygen demand (BOD); Bacillus species HN24 and HN93 were selected as they exhibited rapid oxygen consumption and fast recovery. Improved BOD sensor could be prepared by using mixed microbes (Bacillus subtilis, Bacillus sp. HN24 and Bacillus sp. NH93) and silicon rubber gas-permeable membrane for DO probe, and by bubbling 50% $O_2$ ($N_2$ valence) through background buffer solution. This system exhibited excellent analytical performance resulting in good linearity ($r^2=0.9986$) from 0 to 100 mg/L level of BOD.

• Journal of the Korea Organic Resources Recycling Association
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• v.26 no.3
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• pp.5-14
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• 2018

This study investigated the effect of concentrate of membrane filtration of sewage reuse facilities on bioreactor's microorganisms in sewage treatment facility, and concentrate was analyzed, oxygen uptake rate and continuous activated sludge experiment were performed. As a results, the concentration of organic matter and TP concentration in concentrate was closely related to the concentration of SS and the concentration of ionic substances in concentrate was higher in order of $Cl^-$ > $Na^+$ > $Ca^{2+}$ > $K^+$ > $Mg^{2+}$ > $F^-$. And the analysis value of analytical items was greatly fluctuated according to sampling time of concentrate. Result of OUR test according to the mixing ratio of concentrate to sewage, it was found that the concentrate acts as an organic matter in the activated sludge microorganism and it increases with the increase of the concentrate mixing ratio. As a result of continuous activated sludge experiment, MLSS concentration, organic removal efficiency and TN removal efficiency gradually decreased with increasing concentrate mixing ratio. Based on the experimental results, expected mixing ratio of concentrate to affect the treatment efficiency of activated sludge is 25%.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.162.1-162.1
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• 2015

The use of plasma has increased in bio-application field in recent years. Particularly, water treated by arc discharge or atmospheric pressure plasma has been actively utilized in bio-industry. In this study, we have developed a plasma activated water generating system. For this system, two kinds of plasma sources; dielectric barrier discharge (DBD) plasma and arc discharge plasma have been used. The discharge energy was calculated using the breakdown voltage and current, and the emission spectrum was measured to investigate the generated reactive species. We also analyzed the amount of reactive oxygen and nitrogen species in water using the chemical methods and nitric oxide sensor. Finally, the influence of plasma generated reactive species on the germination and growth of spinach (Spinacia oleracea) was investigated. Spinach is a green leafy vegetable that contains a large amount of various physiologically active organic compounds. However, it is characterized with a low seed germination rate.

• Journal of Environmental Health Sciences
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• v.28 no.1
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• pp.79-84
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• 2002

Entrapped media with cellulous triacetate in which activated sludge was applied to induce operating factors and sewage treatment on site. The results are summarized as follows; The treatment efficiency of entrapped media is 92%, 90% and 80% at the size of 5mm, 7mm, and 12mm, respectively. Also, treatment efficient rate was increased by the packed amount of media in less than 30 % packed, while in more than 40 % packed that was decreased. It takes 10 day to reach the steady states and it is less than the existing activated sludge method. The slopes of oxygen consumption rate are almost parallel both in the entrapped media and free sludge. When organic loading rate is less than 1.0 kg/m$^3$ㆍd on site, it is achieved good removal rate independent of changes of loading rate.

• Journal of Environmental Health Sciences
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• v.34 no.4
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• pp.327-332
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• 2008

To determine structure and activities of microbial communities in a food wastewater treatment system, biofilm of RABC (rotating activated Bacillus contactor) and samples of aeration tanks were analyzed. Heterotrophic bacterial concentrations were similar between biofilm and stage 1 aeration tank and decreased 2-log at stage 3 aeration tank as dissolved oxygen decreased, however portions of Bacillus groups were increased at stage 3 aeration tank. It was revealed by quantitative and qualitative analysis of metabolic fingerprinting patterns of Biolog GN2 plate that RABC represented much higher activities and a different microbial community structure compared to aeration tanks. Metabolic fingerprinting showed the carbon sources that isolated Bacillus groups could or could not use, were used similarly meaning that not only Bacillus groups but also other microbial groups would contribute to the treatment of wastewater.

• 보존과학연구
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• s.11
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• pp.1-9
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• 1990

The environmental controls for good conservation of all textile materials are follow as :1) Special RH conditions on textiles keep to the usually advocated 50∼55%.2) The effect of the temperature is too small to worry about in the applicable range, that is $20^{\circ}C$.3) It is important to keep soiling by air borne dirt to a minimum by an air filter or putting textiles in cases.4) Sulphur dioxide must be rekoved by an activated carbon filter or a water spray. And this concentration below $50\muGm^3$ can be regarded assatisfactory.5) Oxygen plays a part of deterioration proceses. The effect of nitrogend andinert gases in sealed show cases should be further studied.6) Ozone is detrimental to textiles. It can be removed by activated carbonfilter.7) The removal of UV radiation and blue light can be expected to increase the lifetime of dyeing and strength of fiber.50 lux is suggested for sensitive textile materials.

• Journal of the Korean Society of Tobacco Science
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• v.27 no.1 s.53
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• pp.59-67
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• 2005

Activated carbon fiber (ACF) was surface modified by nitric acid to improve the adsorption efficiency of the propylamine. The adsorption amount of propylamine of the modified ACF increased $17\%$ more than that of as-received ACF. Desorption of propylamine from the propylamine saturated ACF was occurred in two steps, the first step started arround $50^{\circ}C$ showing the desorption of physically adsorbed propylamine and the second step started at $200^{\circ}C$ showing the decomposition of chemically adsorbed propylamine. Total desorption amount of propylamine from the modified ACF was larger than that of the as-received ACF because of increased functional groups. The oxygen and nitrogen contents on the modified ACF increased by 1.5 and 3 times compared with the as-received ACF. A part of propylamine adsorbed on ACF formed pyridine-like or pyrrolic structures with 2 carbons exposed on the surface of the ACF. It was found that propylamine reacted with strong or weak acidic functional groups such as -COOH or -OH existed on ACF surface.

• Carbon letters
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• v.11 no.3
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• pp.224-234
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• 2010

Four activated carbons were produced by two-stage process as followings; semi-carbonization of indigenous biomass waste, i.e. cotton stalks, followed by chemical activation with KOH under various activation temperatures and chemical ratios of KOH to semi-carbonized cotton stalks (CCS). The surface area, total pore volume and average pore diameter were evaluated by $N_2$-adsorption at 77 K. The surface morphology and oxygen functional groups were determined by SEM and FTIR, respectively. Batch equilibrium and kinetic studies were carried out by using a basic dye, methylene blue as a probe molecule to evaluate the adsorption capacity and mechanism over the produced carbons. The obtained activated carbon (CCS-1K800) exhibited highly microporous structure with high surface area of 950 $m^2/g$, total pore volume of 0.423 $cm^3/g$ and average pore diameter of 17.8 ${\AA}$. The isotherm data fitted well to the Langmuir isotherm with monolayer adsorption capacity of 222 mg/g for CCS-1K800. The kinetic data obtained at different concentrations were analyzed using a pseudo-first-order, pseudo-second-order and intraparticle diffusion equations. The pseudo-second-order model fitted better for kinetic removal of MB dye. The results indicate that such laboratory carbons could be employed as low cost alternative to commercial carbons in wastewater treatment.

• Carbon letters
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• v.20
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• pp.19-25
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• 2016

Activated carbon fiber (ACF) surfaces are modified using an electron beam under different aqueous solutions to improve the NO gas sensitivity of a gas sensor based on ACFs. The oxygen functional group on the ACF surface is changed, resulting in an increase of the number of non-carbonyl (-C-O-C-) groups from 32.5% for pristine ACFs to 39.53% and 41.75% for ACFs treated with hydrogen peroxide and potassium hydroxide solutions, respectively. We discover that the NO gas sensitivity of the gas sensor fabricated using the modified ACFs as an electrode material is increased, although the specific surface area of the ACFs is decreased because of the recovery of their crystal structure. This is attributed to the static electric interaction between NO gas and the non-carbonyl groups introduced onto the ACF surfaces.