• Journal of Wetlands Research
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• v.18 no.1
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• pp.39-44
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• 2016

The reuse of spent coffee powder has been researched for environmental engineering applications such as adsorbents of organic/inorganic pollutants. In this study adsorption equilibrium tests and adsorption kinetics tests for the removal of aqueous organic pollutant (methylene blue) were conducted using spent coffee powder, granular activated carbon, and powdered activated carbon. It was found that the maximum adsorption capacity of three adsorbents followed the order of powdered activated carbon (178.6 mg/g) > spent coffee powder (60.6 mg/g) > granular activated carbon (15.6 mg/g). The results of adsorption kinetics tests also indicated that spent coffee powder had higher kinetic parameters than granular activated carbon for pseudo 1st and 2nd order kinetics. The high performance of spent coffee powder might be due to its porous surface like those of granular and powdered activated carbons and smaller particle size comparing with granular activated carbon.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.2
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• pp.119-124
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• 2009

The aim of this study was to investigate the influence of ionic strength and iron impregnation on the attachment of Enterococcus faecalis to granular activated carbon (GAC). Column experiments were performed to examine bacterial adhesion to coconutbased GAC (c-GAC), iron-impregnated c-GAC (fc-GAC), acid-washed c-GAC (a-GAC) and iron-impregnated a-GAC (fa-GAC) under two different solution (NaCl 1, 10 mM) conditions. Results showed that bacterial mass recovery in c-GAC decreased from 77.3 to 61.6% while in a-GAC it decreased from 71.6 to 32.3% with increasing ionic strength from 1 to 10 mM. This indicates that bacterial attachment to GAC can be enhanced with increasing ionic strength. Results also showed that the mass recoveries in fc-GAC were 62.6% (1 mM) and 53.3% (10 mM) while they were 50.8% (1 mM) and 16.9%(10 mM) in fa-GAC, which were lower than those in c-GAC and a-GAC. This demonstrates that bacterial adhesion to GAC can be enhanced through iron impregnation. This study provides information regarding the effects of ionic strength and iron impregnation on bacterial attachment to GAC. Furthermore, this study will advance our knowledge of bacterial removal in surface-modified granular media.

• Clean Technology
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• v.23 no.1
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• pp.113-117
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• 2017

We prepared sodium carbonate impregnated activated carbon fiber and evaluated its availability for hydrogen sulfide removal by the comparison with the counterpart, sodium carbonate granular impregnated activated carbon. The sodium carbonate impregnated concentration and immersion duration were chosen as two primary parameters. First, the hydrogen sulfide adsorption capacity increased in proportion to the impregnated concentration up to 3 wt%, above which the sodium carbonate impregnated amount rarely showed an increase due to the pore filling effect for both cases. The optimal impregnated concentration was thus set to 3 wt%. Meanwhile, impregnated activated carbon fiber required only half of the immersion duration compared with granular impregnated activated carbon, while showing a 30% increase on the hydrogen sulfide removal capacity. The greater specific area of impregnated activated carbon fiber explained it. In conclusion, we evaluated advantage of preparation time and improved hydrogen sulfide adsorption capacity by impregnate sodium carbonate, which is capable of reacting with hydrogen sulfide chemically, onto the activated carbon fiber with improved specific area.

• 한국상하수도협회지
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• s.10
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• pp.44-47
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• 2005

• The Journal of the Korea Contents Association
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• v.17 no.12
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• pp.64-76
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• 2017

Biolgical activated carbon (BAC) processes are known to effectively remove organic pollutants in raw water, and biomass and attached bacterial species play an important role in removing process. In the present study, changes of bacterial biomass in granular activated carbon (GAC) process according to the depth and operating period were investigated. In addition, changes of bacterial biomass were also confirmed after UV exposure prior to the GAC process. Results from this this study showed that the bacterial biomass was decreased dependently according to the depth of GAC process. In case of UV pre-treatment, the bacterial biomass was declined significantly over the period of operation. However, changes in bacterial community were not shown during operation period without UV pre-treatment process. In conclusion, findings from this study may provide the useful information about the management of BAC process.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.674-677
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• 2012

본 연구에서는 기존 매립이나 지반보강재로 사용되던 소각재 용융슬래그를 고부가가치 수처리 여재로 활용하기 위하여 형광성 박테리아를 통한 Microtox 생물검정법으로 독성을 평가하였다. 소각재 용융슬래그의 독성평가 대조군으로는 기존의 수처리 여재인 입상활성탄(석탄계/야자계/목탄계), PP PE펠렛(Poly-Propylene Poly-Ethylene pallet), 표준여과사를 비교하였으며, 시료의 용출시험은 US EPA에서 제안한 TCLP 방법을 사용하였다. Microtox Acute Toxicity 평가 결과, 독성순위는 석탄계 입상 활성탄, 소각재 용융슬래그, 목탄계 입상활성탄, 야자계 입상활성탄, 표준여과사, PP PE 순으로 나타났으며, 실험에 사용된 모든 수처리 여재들은 급성독성을 고려하지 않는 무독성으로 나타났다. 따라서 소각재 용융슬래그가 수처리를 목적으로 수체에 편입시켜도 기존의 수처리 여재들과 비교할 때 수환경에 미치는 영향은 미미할 것으로 판단된다.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2008.11a
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• pp.495-498
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• 2008

여러 가지 흡착제를 사용한 회분식 흡착성능 측정 실험에서 흡착성능은 음이온교환수지 > 입상활성탄 > Biomass > 분말활성탄 > 제올라이트 순으로 나타났으며, 모든 흡착제는 30분 안에 흡착평형 상태에 도달 하였다. 음이온교환수지를 이용한 회분식 흡착실험에서 최대흡착량은 pH 10에서 0.0483 mmol/g로 가장 높았고, 대체적으로 pH가 높은 범위에서 흡착이 잘 되는 것으로 밝혀졌다. 이것은 산화물 상태의 셀레늄이 pH 6 이하의 영역에서는 HSeO$_3^{-}$가 존재하며, PH 6$\sim$10 영역에서는 HSeO$_3^{-}$와 SeO$_3^{-2}$가 공존하며, pH 10 이상에서는 SeO$_3^{-2}$만 존재함을 알 수 있는데, 실험에서도 유사한 결과가 나온 것으로 사료된다. 입상활성탄을 이용한 흡착실험에서 최대흡착량은 pH 4.5에서 0.0574 mmol/g으로 가장 높았다. pH 4.5$\sim$6.5 범위에서는 대체적으로 비슷한 성능을 나타내었다. 입상활성탄의 표면전위 특성상 음이온으로 존재하는 셀레늄과 정전기적 반발력으로 인해 흡착이 거의 일어나지 않는 것으로 보이지만, 음이온 상태로 존재하는 셀레늄 이외의 금속간 화합물이나 물리적인 결합상태의 미세입자들이 흡착된 것으로 보인다.

• Applied Chemistry for Engineering
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• v.8 no.5
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• pp.737-741
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• 1997

The typical removal method of volatile organic compounds is adsorption process. In this study, granular activated carbon and activated carbon fiber were used as adsorbents, and the adsorption behavior for the two types of adsorbent was compared. And they were regenerated by supercritical carbon dioxide extraction at a constant temperature, 318.15 K, and 2000, 2500, 3000 psi respectively. The desorption percentage of initial adsorbates and iodine values were increased with pressure of supercritical carbon dioxide. The regeneration time was 70 and 60 minutes in adsorbents loaded with methyl ethyl ketone(MEK) and benzene, respectively. The desorption percentages were 64.0% for granular activated carbon and 55.3% for activated carbon fiber loaded with MEK, and 59.1% for granular activated carbon and 45.2% for activated carbon fiber loaded with benzene. The exit concentration could be evaluated by Tan and Liou model. Therefore, the granular activated carbon and the activated carbon fiber could be regenerated by supercritical fluid extraction process.

• Journal of Soil and Groundwater Environment
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• v.13 no.3
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• pp.21-26
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• 2008

Nitrate adsorption from aqueous solutions onto zinc chloride ($ZnCl_2$) treated coconut Granular Activated Carbon (GAC) was studied in a batch mode at two different initial nitrate concentrations (25 and 50 mg/L). The rate of nitrate uptake on prepared media was fast in the beginning, and 50% of adsorption was occurred within 10 min. The adsorption equilibrium was achieved within one hour. The mechanism of adsorption of nitrate on $ZnCl_2$ treated coconut GAC was investigated using four simplified kinetic models : the rate parameters were calculated for each model. The kinetic analysis indicated that pseudo-second-order kinetic with pore-diffusion-controlled was the best correlation of the experimental kinetic data in the present adsorption study.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.10
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• pp.709-714
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• 2012

This study accessed the adsorption characteristics of the nine nitrosamine species on coal-based granular activated carbon (GAC). The breakthrough appeared first for NDMA and sequentially for NMOR, NPYR, NMEA, NDPA, NDEA, and NPIP. On the other hand, NDBA and NDPHA were not detected in the treated effluent for the operation period. The maximum adsorption capacity (X/M) for the seven nitrosamine species with apparent breakthrough points ranged from $27.5{\mu}g/g$ (for NDMA) to $671.0{\mu}g/g$ (for NPIP). Carbon usage rate (CUR) for NDMA was 1.07 g/day, 13.4 times higher than that for NPIP (0.08 g/day). The X/M values for the seven nitrosamine species were fitted well with a linear regression ($r^2$ = 0.94) by their octanol-water partitioning coefficient ($K_{ow}$).