• Title/Summary/Keyword: 흡착률

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Analysis of Hydrophobic Membrane Fouling on the COD Loading Rates at the State of Passive Adsorption in Membrane Bioreactor (생물학적 막분리 공정에서 수동흡착 상태에서의 유기물 유입 부하에 따른 소수성 막의 오염도 분석)

  • Park, Tae-Young;Choi, Changkyoo
    • Journal of Korean Society of Environmental Engineers
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    • v.37 no.3
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    • pp.152-158
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    • 2015
  • This paper investigated the membrane fouling potential at the state of passive adsorption which is no permeation with the test modules on COD (Chemical oxygen demand) loading rates, examined the recovery rate and resistance on membrane fouling by three cleaning manners of hydrophobic membrane in a bioreactor. The results showed that high COD loading led to the increase of extra-cellular polymeric substances and filtration resistance. The permeability resistance from 1st day to 63rd day was getting increased, however, the value of permeability resistance after 63th day during the operation period was almost same level at three COD loading rates, it was due that the biomass adhesion on membrane surface at the state of passive adsorption reached to the critical state. Also, the final recovery rates after three cleaning manners were 78%, 72% and 69% at the COD loading concentrations of 250 mg/L, 500 mg/L and 750 mg/L respectively, and then recovery rate by physical cleaning at Run 2 and Run 3 was decreased after 40th day, it proved that biomass cake, which is not easily removed, was formed on the membrane surface because of high COD loading rate and EPS concentration.

Hydrogen Adsorption on the Stepped Planes of Tungsten : I. (210) Plane (Stepped 텅스텐 결정면의 수소 흡착에 관한 연구 : I.(210)면)

  • 최대선;한종훈;백선목;박노길;김기석;황정남
    • Journal of the Korean Vacuum Society
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    • v.4 no.2
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    • pp.142-149
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    • 1995
  • 본 연구에서는 새로운 장전자 방출법(DOFEC법)으로 W(210)면의 수소 흡착에 의한 일함수의 변화, heat of desorption에 대하여 연구하였다. 텅스텐(210)면에 수소가 흡착될 때 흡착율에 따라 일함수가 증가하다가 다시 감소하는데 이것은 수소가 처음에는(210)면의 step((100)면)에 흡착되고 dose를 증가시킴에 따라 terrace((110)면)에 흡착되기 때문임을 알았다. 즉, terrace보다 step의 sticking coefficient가 더 크며 zero coverage에서의 그 비는 2.57이며 이는 타 연구 결과와 잘 일치한다. (210)면의 step과 terrace의 수소 흡착에 대한 일함수의 정량적인 변화량 그리고 수소 dose량에 대한 각각의 면에 대한 상대적인 흡착율을 얻었으며, 이 결과는 독립된(110)면 또는 (100)면의 결과와 잘 일치됨을 알았다. 또한 이 결과는 흡착 실험에 있어서 dose량을 흡착률로 환산하는데 사용될 수 있다. 텅스텐(210)면에는 4개의 흡착 site가 존재하며 이 site들 중 $\beta$2과 $\beta$4 state는 second order 탈착 과정을 따르며 $\beta$1과 $\beta$3 state는 first order 탈착과정을 따른다. 따라서 텅스텐(210)면에는 수소가 해리적 흡착을 함과 동시에 비해리적 흡착도 함을 알았으며(210)면의 각 흡착 site를 이에 대응되는 (100)면과 (110)면의 흡착 site와 비교 검토하였다.

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The Study of Adsorption and Decomposition Reaction on the Sulfided Mo Single Crystal Surface (황화된 Mo 단결정 표면에서 Furan의 흡착 및 분해반응 연구)

  • ;Philip R. Watson
    • Journal of the Korean Vacuum Society
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    • v.4 no.2
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    • pp.150-155
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    • 1995
  • Mo 단결정 표면에 황을 흡착시켜 형성된 상층구조를 AES와 LEED로써 연구하였다. 황의 피복률은 sulfur gun으로부터 생성되는 S2 flux로써 조절하였으며, 여러 가지 흡착된 황의 상층구조를 LEED로써 관찰하였다. 황화된 Mo 표면에서 탈산소반응(HDO)의 모델 분자로서, Furan의 흡착과 반응을 승온반응분광법(TPRS)으로 조사하였다. 낮은 온도에서 Furan 분자의 헤테로 원자는 직접 이탈하여 안정한 기체상의 반응 생성물인 일산화탄소를 형성하였으며, 이 반응은 Mo의 (100) 및 (110)면에서 각각 깨끗한 표면 및 황화된 표면에 관계없이 일어났다. 이를 바탕으로 Mo 표면에서 Furan의 분해반응에 대한 메카니즘을 제안하였다.

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Removal Characteristics of Mixed Heavy Metals from Aqueous Solution by Recycled Aggregate as Construction Waste (건설폐기물인 순환골재를 이용한 수용액상에서의 혼합 중금속 제거 특성)

  • Shin, Woo-Seok;Kim, Young-Kee
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.16 no.2
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    • pp.115-120
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    • 2013
  • This study examined the removal rate of mixed heavy metals from aqueous solution using recycled aggregate. The recycled aggregate is favorable for the absorbent because it contains about 95% (CaO, $SiO_2$, $Al_2O_3$ and $Fe_2O_3$), which are major ingredient of adsorbent for heavy metal. The kinetic data presented that the slow course of adsorption follows the Pseudo first and second order models. The equilibrium data were well fitted by the Langmuir model and showed the affinity order: $Cu^{2+}$ > $Pb^{2+}$ > $$Zn^{2+}{\simeq_-}Ni^{2+}$$ > $Cd^{2+}$. The results also showed that adsorption rate slightly increased with increasing pH from 6 to 10. Moreover, this trend is similar to results obtained as function of loading amount of recycled aggregate. Meanwhile, an unit adsorption rate was slightly decreased. From these results, it was concluded that the absorbents can be successfully used the removal of the heavy metals from the aqueous solutions.

The Evaluation of Adsorption Characteristics of Perfluorinated Compounds (PFCs) in GAC Process Using Continuous Column Adsorption Test (연속 컬럼흡착 실험을 이용한 GAC 공정에서의 과불화 화합물(PFCs) 흡착 특성 평가)

  • Son, Hee-Jong;Yoo, Soo-Jeon;Jang, Seung-Ho
    • Journal of Korean Society of Environmental Engineers
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    • v.35 no.3
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    • pp.206-212
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    • 2013
  • This study accessed the adsorption characteristics of the 11 perfluorinated compounds (PFCs) on coal-based granular activated carbon (GAC). The breakthrough appeared first for PFODA and sequentially for PFHDA, PFTeDA, PFTDA, PFDoDA, PFUnDA, PFDA, PFNA, PFOA, PFOS, and PFHpA. The maximum adsorption capacity (X/M) for the 11 PFCs with apparent breakthrough points ranged from 2.43 ${\mu}g/g$ (for PFODA) to 64.5 ${\mu}g/g$ (for PFHpA). Carbon usage rate (CUR) for PFODA was 0.291 g/day, 11.2 times higher than that for PFHpA (0.026 g/day). The X/M values for the 11 PFCs were fitted well with a linear regression ($r^2$ = 0.89) by their molecular weight (chain length).

Effect of Salicylic and Picolinic Acids Acids on the Adsorption of U(VI) onto Oxides (산화물 표면의 U(VI) 흡착에 미치는 살리실산과 피콜린산의 영향)

  • Park, Kyoung-Kyun;Jung, Euo-Chang;Cho, Hye-Ryun;Song, Kyu-Seok
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.7 no.4
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    • pp.219-227
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    • 2009
  • The effect of organic acids on the adsorption of U(VI) onto oxide surfaces ($TiO_2)$(anatase), $SiO_2$(amorphous) and $Al_2O_3$(amorphous)) has been investigated. Two different organic acids, salicylic and picolinic acids, were used. Changes of adsorption ratio of U(VI), which depend on the existence of organic acids in a sample, were measured as a function of pH. Quantities of adsorbed organic acids, which depend on the existence of U(VI) in a sample, were also measured as a function of pH. It is confirmed that the soluble complex formation of U(VI) with organic acids can deteriorate the adsorption of U(VI) onto $TiO_2$ surface. It is noteworthy that salicylic acid does not affect the adsorption of U(VI) onto $SiO_2$ surface, however, picolinic acid enhances the adsorption of U(VI) onto $SiO_2$ surface. The latter effect can be understood by considering the formation of a ternary surface complex on $SiO_2$ surface, which was confirmed by the co-adsorption of picolinic acid with U(VI) and the change in a fluorescence spectra of U(VI) on surface, In the case of $Al_2O_3$, organic acids themselves were largely adsorbed onto a surface without deteriorating the adsorption of U(VI). This would support the possibility of a ternary surface complex formation on the $Al_2O_3$ surface, and an additional spectroscopic study is required.

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Phosphate Adsorption of Kaolinite KGa-1b (Source Clay) (카올리나이트 KGa-1b(표준 점토)의 인산염 흡착 특성)

  • Cho, Hyen-Goo;Johnston Cliff T.;Gnanasiri S. Premachandra G.S.
    • Journal of the Mineralogical Society of Korea
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    • v.19 no.4 s.50
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    • pp.247-258
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    • 2006
  • The characteristics of phosphate adsorption on kaolinite was studied by batch adsorption experiments. The phosphorous contents was measured using UV spectrometer with 820 nm wavelength. The experiment with changing reaction time revealed that fast P adsorption occurred within $0{\sim}12$ hour, whereas slow adsorption reaction began after 12 hour. The adsorption percentage depended on kaolinite amount in phosphate solution. Rotary-shaker enhanced the adsorption percentage up to $11{\sim}15%$. The phosphorous adsorption appears to be insensitive to change in the ionic strength of KCl between 0.01 M and 0.1 M. From this result, we can conclude that phosphate was adsorbed on kaolinite as inner-sphere complexes. However, the ionic strength increased to 1.0 M, adsorption decreased. It suggests that phosphate may be adsorbed as outer-sphere complexes. Phosphate adsorption decreased with increasing pH value, but it is not distinct. The adsorption isotherms were well fitted with the Langmuir equation.

A Study on the Flow Loss of Cement-Based Composites Using High Range Water Reducing Admixture (고성능감수제를 사용한 시멘트복합체의 유동성 손실에 대한 연구)

  • 문한영;김기형
    • Magazine of the Korea Concrete Institute
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    • v.4 no.2
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    • pp.119-126
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    • 1992
  • 고강도 시멘트 복합체의 유동성 손실을 감소시키기 위한 연구의 일환으로 시멘트계 입자에 대한 고성능감수제의 흡착특성, 현탄액 속에서의 응집특성을 관찰하여 시멘트풀과 모르터의 유동성과 관련시켜 고찰하였다. 본 연구결과 알루미네이트계 화합물이 많이 함유된 보통포틀랜드 시멘트의 흡착률이 가장 크며, 시멘트풀 및 모르처의 유동성 손실이 작았으며 나프탈린계 고성능 감수제가 유동성 손실면에서 얼마간 유리하였다.

Adsorption Behaviors of Nickel ton on the Waste Pulp Produced in the Paper Recycling Process (고지(古紙) 재생(再生) 과정(過程)에서 발생(發生)하는 폐(廢)펄프를 흡착제(吸着劑)로 이용(利用)한 니켈 폐수(廢水) 처리(處理) 특성(特性))

  • Baek, Mi-Hwa;Shin, Hyun-Young;Kim, Dong-Su
    • Resources Recycling
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    • v.15 no.3 s.71
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    • pp.58-65
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    • 2006
  • The applicability of the waste pulp which produced in the paper recycling process as an adsorbent for the treatment of $Ni^{2+}$ ion in wastewater has been investigated taking the initial concentration of adsorbate, temperature, the amount of adsorbent, and solution pH as the experimental variables. In addition, the effect of the concentration of coexisting solute and pre-treatment of adsorbent on the adsorbability of $Ni^{2+}$ ion were also examined. The electrokinetic potential of waste pulp was observed to be positive below pH 7.8 and negative above this pH. The adsorption reaction of $Ni^{2+}$ ion reached its equilibrium within 4 hours after the reaction was initiated and the adsorbed amount of adsorbate was found to increase with its initial concentration. The adsorbability of $Ni^{2+}$ was raised with temperature so that its adsorption reaction was considered to be exothermic, which was substantiated by thermodynamic calculation. Also, the adsorbed amount of $Ni^{2+}$ was raised with the amount of waste pulp and with pH in the range of pH $3{\sim}6$. This behavior of the adsorption of $Ni^{2+}$ according to the solution pH was well agreed with the electrokinetic characteristics of waste pulp in solution. The amount of coexisting solute was observed to reversely affect on the $Ni^{2+}$ adsorption onto waste pulp under the experimental conditions. With regard to the pre-treatment of adsorbent with NaOH, the adsorbability of $Ni^{2+}$ was increased with the concentration of NaOH to a certain extent. However, it was found to decrease contrarily when the concentration of NaOH became too high.

Separation of Vanadium and Tungsten from Simulated Leach Solutions using Anion Exchange Resins (음이온교환 수지를 이용한 바나듐/텅스텐 혼합용액으로부터 바나듐/텅스텐 분리회수에 관한 연구)

  • Jong Hyuk Jeon;Hong In Kim;Jin Young Lee;Rajesh Kumar Jyothi
    • Resources Recycling
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    • v.31 no.6
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    • pp.25-35
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    • 2022
  • The adsorption/desorption behavior and separation conditions of vanadium and tungsten ions were investigated using a gel-type anion-exchange resin. In the adsorption experiment with the initial acidity of the solution, the adsorption rate of vanadium was remarkably low in strong acids and bases. Additionally, the adsorption rate of tungsten was low in a strong base. An increase in the reaction temperature increased the adsorption reaction rate and maximum adsorption. The effect of tungsten on the maximum adsorption was minimal. The adsorption isotherms of vanadium and tungsten on the ion-exchange resin were suitable for the Langmuir adsorption isotherms of both the ions. For tungsten, the adsorption isotherms of vanadium and tungsten were polyoxometalate. Both ion-exchange resins were simulated using similar quadratic reaction rate models. Vanadium was desorbed in the aqueous solutions of HCl or NaOH, the desorption characteristics of vanadium and tungsten depended on the desorption solution, and tungsten was desorbed in the aqueous solution of NaOH. It was possible to separate the two ions using the desorption process. The desorption reaction reached equilibrium within 30 min, and more than 90% recovery was possible.