• 한국물환경학회지
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• 제26권4호
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• pp.585-589
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• 2010

In order to evaluate the performance of a powdered activated carbon (PAC) contactor, two water treatment plants (WTP) were selected as target sites. The result of tracer tests showed that the plug flow portion of a bisymmetry-type contactor (H WTP) was more than 70%. A maze-type contactor (C WTP) also had more than 70% of plug flow portion after intra-basin baffles were installed. According to the operating data of the target WTPs, there was no clear evidence that the addition of PAC contributed to the removal of organics. However, the results of jar tests, conducted with the raw water taken from the H WTP, proved that PAC could remove dissolved organic carbon (DOC) to some extent when the proper velocity gradient was maintained. It was estimated that the production rate, defined as the ratio of the operating flowrate to the design flowrate, of the C and H WTPs was only 27 and 50%, respectively. Because of these lower production rates, the mixing intensity in the contactor was much less than the designed value and, finally, the performance of the PAC contactor was much lower than what was expected.

• 상하수도학회지
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• 제18권5호
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• pp.619-627
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• 2004

Purposes of this study were to examine closely the extracellular polymeric substances (EPS) which was a membrane fouling contaminant, to control detected EPS by powdered activated carbon (PAC) dosage etc. and to evaluate the possibility of practical reuse facility. With high removal efficiency of general pollutants, when the PAC is added to MBR, improvement of removal efficiency of $COD_{cr}$, and color was expected and treated wastewater can be reused. It was judged that the correlation between EPS and membrane fouling was very high. Carbohydrate and DNA in the EPS were judged to be cause of membrane fouling. If EPS could be controled, not only membrane fouling would be decreased but also operation time would be extended. In experiment of powdered activated carbon (PAC), characteristics of the best PAC for membrane fouling control were the particle size of $7{\mu}m$, lodine Number of 1,050, surface area of peat of $1,150m^2/g$. In lab test, operation time of MBR by PAC dosage of 200mg/gVSS was longer than one of MBR by without PAC dosage. Because EPS, especially carbohydrate and DNA, was controled successfully by PAC, membrane fouling in MBR could be decreased.

• 한국물환경학회지
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• 제28권3호
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• pp.479-482
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• 2012

Membrane process has been one of the widely applied wastewater treatment options, especially in field. However, one of the tricky issues in the process is to treat concentrates generated from reverse osmosis (RO) system in a manner of saving cost with maximum efficiency for treating a wide range of contaminants. Stimulated with the challenging issues, we have conducted a series of experimental studies in the evaluation for removing organics and nutrients using activated carbon. Results indicated that while powdered activated carbon (PAC) efficiently removed organics and the extent of removal was proportional to the PAC dosage, little removal of nitrogen and phosphorus was observed despite increasing the PAC dose. Interestingly, applying PAC was superior in removing organics than using granular activated carbon (GAC). These results suggest smaller particle size with higher surface area could provide greater chemical reactivity in removing organics.

• 상하수도학회지
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• 제21권3호
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• pp.341-348
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• 2007

The efficiency of powdered activated carbon (PAC) for removing taste and odor (T&O) in drinking water supplies is dependent on the contact time, quality of mixing, and the presence of competing compounds. All of these are strongly influenced by the stage in the treatment process at which the PAC is added. In conventional water treatment plants (WTPs), PAC is commonly added into the rapid mixing basin where chemicals such as coagulants, alkaline chemicals, and chlorine, are simultaneously applied. In order to prevent interference between PAC and other water treatment chemicals, alternative locations for addition of PAC, such as at transmission pipe in the water intake tower or into a separated PAC contactor, were investigated. Whatever the location, addition of PAC apart from other water treatment chemicals was more effective for geosmin removal than simultaneous addition. Among several combinations, the sequence 'chlorine-PAC-coagulant' produced the best result with respect to geosmin removal efficiency. Consequently, when PAC has to be applied to cope with T&O problems in conventional WTPs, it is very important to prevent interference with other water treatment chemicals, such as chlorine and coagulant. Adequate contact time should also be given for adsorption of the T&O compounds onto the PAC. To satisfy these conditions, installation of a separated PAC contactor would be the superior alternative if there is space available in the WTP. If necessary, PAC could be added at transmission pipe in the water intake tower and still provide some benefit for T&O treatment.

• 분석과학
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• 제18권5호
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• pp.436-443
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• 2005

활성탄 미분을 용액계에 분산하므로 수반 되는 결과를 고찰하기 위하여 칼륨처리 미분 활성탄의 물리적 성질과 그들에 응용에 대한 연구를 수행하였다. 오염수로부터 오염물질의 촉매적 제거 효율을 연구하기 위하여 분산매로써 두 종류의 칼륨 미분 활성탄을 사용하였다. 칼륨염을 포함하는 수용액내에서 처리된 활성탄 시료로부터 얻어진 표면 특성화를 위하여, 흡착 등온곡선 형태, SEM, EDX 및 표면 기능기 변화 등을 주된 연구 대상으로 하였다. pH 변화에 따른 칼륨 미분 활성탄을 오염수에 분산하여 색도, COD, T-N 및 T-P 등에 대하여 제거 효율을 연구하였다. 칼륨 미분 활성탄을 처리한 오염수에 대한 네 가지 요소 제거 결과로부터, pH 6~8의 범위에서 만족할 만한 제거 효율이 얻어 졌다. 본 연구로부터 칼륨 처리 미분 활성탄의 분산에 의한 오염물질의 제거 효율이 흡착 특성 및 촉매적 효율에 의하여 입증되었다.

• 한국환경과학회지
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• 제9권5호
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• pp.409-414
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• 2000

In order to examine the availability and effectiveness of crab shell for the removal of heavy metals in aqueous solution the crab shell was compared with cation exchange resin(CER), zeolite granular activated carbon (GAC) and powdered activated carbon(PAC) on aspects of heavy metal removal capacity rate and efficiency. In the removal of Pb, Cd and Cr, the heavy metal removal capacity of crab shell was higher than those of any other sorbents (CER, zeolite, GAC, PAC) and the order of heavy metal removal capacity was crab shell>CER>zeolite>PAC GAC. However in the removal of Cu, the result of crab shell was slightly lower than that of CER. The initial heavy metal removal rate was affected by the sorts of sorbents and metals. In all heavy metals the heavy metal removal rate of crab shell was higher than those of any other sorbents. Under the heavy metal concentration of 1.0 mmole/$\ell$ the heavy metal removal efficiency of crab shell was maintained as 93~100% which was much higher than those of any other sorbents.

• 한국물환경학회지
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• 제22권6호
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• pp.996-1003
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• 2006

The absorption characteristics of powdered activated carbon doped by transition-metal nanoparticles were investigated to enhance the remove efficiencies of $TCOD_{Mn}$ and Color from the flexo-inks wastewater. According to the adsorption dynamics of PAC and MPAC, the optimal dosage of activated-carbon adsorbents was 3 g/L under the reaction conditions of pH6.0, 30 mill of reaction time, 240 rpm of mixing intensity. The removal efficiencies by the optimal dosages were maximized as 19% $TCOD_{Mn}$, 57% Color for PAC and 88% $TCOD_{Mn}$, 95% Color for MPAC. Freundlich indexes of isotherm absorption were estimated as follows: i) For PAC, k=-8.11, 1/n=2.98, r=0.91 in the raw water, and k=0.14, b/n=0.75, r=0.96 in the biological treatment water, ii) For MPAC, k=2.69, 1/n=0.21, r=0.80 in the raw water, and k=0.74, 1/n=1.17, r=0.95 in the biological treatment water. MPAC (Powdered activated carbon doped by transition-metal nanoaprticles) was very effective in the removal of organics from the raw water and biological treatment water, as Freundlich indexes of 1/n for both types of water were estimated less than 2.0.

• 상하수도학회지
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• 제14권4호
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• pp.350-355
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• 2000

Powdered activated carbon(PAC) is widely used to control 2-MIB와 geosmin causing earthy-musty odor in water supplies. It was known that chlorine is one of the chemicals often come into contact with activated carbon. But activated carbon react with chlorine and surface oxide accumulate on carbon surface. As result, adsorption capacity of activated carbon is reduced. To investigate the effect of chlorine on the PAC's ability to adsorb 2-MIB and Geosmin, a series of experiments was carried out to show (1) the effect of aqueous chlorine doses on the ability of PAC to adsorb 2-MIB and Geosmin from Lake Heodong water. (2) the effect of delaying the chlorine addition after PAC had been added (to simulate the effect of using an alternative point of chlorine addition). As a result of experiment, as chlorine dose increased correspondingly decreased the capacity of activated carbon to adsorb 2-MIB and geosmin. Even though previously adsorbed 2-MIB and geosmin released, as result of the application of delaying the chlorine adding was more beneficial than simultaneous adding chlorine with PAC.

• Membrane and Water Treatment
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• 제13권2호
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• pp.73-83
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• 2022

In the present study, we compared the adsorption capacity of Pb (II) from contaminated water of used cardboard (UC) and a commercial powdered activated carbon (PAC), the latter has been characterized by different techniques, namely X-ray diffraction (XRD), scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS), wavelength dispersion x-ray fluorescence (WDXRF), infrared spectroscopy (IR) and surface area B.E.T analyzer. The effect of various parameters, such as the pH, the contact time, the amount of adsorbent, and the temperature on the adsorption of Pb (II) on both materials was investigated. The Pb (II) adsorptions are perfectly described by a pseudo-second-order model, while the intraparticle diffusion is a decisive step after the first minutes of contact. The fit to the Langmuir and Redlich-Peterson models seems perfect for these adsorption reactions. (PAC) showed a greater affinity for Pb (II) compared to (UC) and the adsorption of Pb (II) ions is strongly pH-dependent, on the other hand, the increase in temperature doesn't have much influence on the two solids. This study showed that the capacity of (UC) to adsorb Pb (II) from an aqueous solution is greater than two-thirds of that of (PAC).

• Environmental Engineering Research
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• 제23권3호
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• pp.301-308
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• 2018

We investigated simultaneous removal of heavy metals such as Cr, Ni, and Zn by adsorption onto powdered activated carbon (PAC) and PAC modified with sodium diethyldithiocarbamate (PAC-SDDC). Modification of PAC was confirmed by Fourier transform infrared spectroscopy and Scanning electron microscopy and energy dispersive X-ray spectroscopy. Both PAC and PAC-SDDC reached adsorption equilibrium within 48 h, and the adsorption kinetics followed a pseudo-second order reaction kinetics. The removal of metals was enhanced with increasing both adsorbent dosage and followed the descending order of Cr > Ni > Zn for PAC and Cr > Zn > Ni for PAC-SDDC, respectively. Adsorption kinetics followed pseudo-second order kinetics. Adsorption kinetic results were well fitted by the Freundlich isotherm except for Cr adsorption onto PAC. The optimum pH for heavy metal adsorption onto PAC was 5, whereas that for PAC-SDDC ranged from 7 to 9, indicating that modification of PAC with SDDC significantly enhanced heavy metal adsorption, especially under neutral and alkaline pH conditions. Our results imply that SDDC modified PAC can be applied to effectively remove heavy metals especially Cr in plating wastewaters without adjusting pH from alkaline to neutral.