• Title, Summary, Keyword: adsorption rate

Search Result 987, Processing Time 0.039 seconds

Adsorption Characteristic of Endo I and Exo II Purified from Cellulase by Trichoderma viride on Celluloses with Different Crystallinity (결정성이 다른 셀룰로오스에 대한 Trichoderma viride속 Cellulase로부터 분리한 Endo I 및 II의 흡착특성)

  • 김동원;홍영관;장영훈;이재국
    • KSBB Journal
    • /
    • v.13 no.2
    • /
    • pp.162-167
    • /
    • 1998
  • The adsorption behaviors of two major cellulase components, endo I and exo II, from Trichoderma viride were investigated using $\alpha$-celluloses with different correlation crystallinity index(Cc) as substrates. The adsorption of cellulase enzyme components was significantly affected by the reaction condition and the physicochemical properties of the cellulose. The $\alpha$-cellulose was hydrolyzed in the presence of cellulase for various periods. The correlation crystallinity index of $\alpha$-cellulose increased with increasing the hydrolysis time. The adsorption was apparently found to obey the first-order kinetics, and the adsorption activation energy(Ea) was calculated from the adsorption rate constant(ka). The value of adsorption rate constant for endo I was larger than that of exo II. This means that endo I are adsorbed more rapidly than exo II. With the increase in correlation crystallinity index, the values of the adsorption rate constants for endo I and exo II decreased, respectively. The activation energy for the adsorption of exo II on the cellulose also was larger than that of endo I. Also adsorption activation energy of endo I and exo II increased with an increase in the crystallinity of sample cellulose.

  • PDF

Adsorption and Desorption Characteristics of Fission Molybdenum on Alumina (알루미나에 의한 Fission 몰리브덴의 흡착과 탈착 특성)

  • 조경태;정원명;이종대
    • Journal of the Korean Society of Safety
    • /
    • v.12 no.3
    • /
    • pp.97-105
    • /
    • 1997
  • Mo-99(Molybdenum) is the only source of Tc-99m(Technetium) which is most frequently used in nuclear medical diagnostics and the demand is on the increase recently. Separation and refining of Mo-99 was investigated by adsorption and desorption on alumina. At pH=0.63, adsorption isotherm of Mo was fitted by Redlich & Peterson equation using the adsorption experimental data. It was found that the pore diffusion model ($D_p=1.4{\times}10^{-6}cm^2/s, K_f/=0.4 cm/s$) agreed well with batch adsorption experimental data. RTDs(Residence Time Distributions ) were measured and axial dispersion coefficients were obtained in the fixed bed absorber according to the changes of the flow rate using 0.05% -NaCl. From the adsorption experimental data, it was shown that the behavior of breakthroughs depended on flow rate. Mo recovery yield was increased as adsorption flow rate was increased and desorption flow rate was decreased.

  • PDF

Adsorption of gold from cyanide leaching solution onto activated carbon originating from coconut shell-Optimization, kinetics and equilibrium studies

  • Khosravi, Rasoul;Azizi, Asghar;Ghaedrahmati, Reza;Gupta, Vinod Kumar;Agarwal, Shilpi
    • Journal of Industrial and Engineering Chemistry
    • /
    • v.54
    • /
    • pp.464-471
    • /
    • 2017
  • This study investigates the behavior of gold adsorption from cyanide leaching solution onto activated coconut shell carbon. The experimental was designed according to CCD implemented with RSM and a quadratic model was developed for regression analysis. The effects of important parameters including pH, agitation rate, adsorbent concentration and adsorption time were studied to find the best operating conditions, and the optimized value of pH, agitation rate, activated carbon concentration and adsorption time was found to be 11, 40 rpm, 1.25 g/L and 3 h, respectively. Under these conditions, the adsorption rate was found to be about 87.11%. Also, the optimal conditions were established on industrial cyanide leaching solution and the results demonstrated that adsorption rate of gold could be obtained about 89.25%. Adsorption behavior was kinetically investigated using pseudo first-order and pseudo second-order models among which data were mostly correlated to pseudo first-order model. The further analysis of kinetics indicated that intra-particle diffusion was the rate-limiting step. Adsorbate-adsorbent interactions at 298 k was assessed by Langmuir, Freundlich, and Temkin isotherm models from which Freundlich model had the highest consistency with the experimental data.

Adsorption of Heavy Metal Ions(Cadmium etc.) using Chitosan Bead (Chitosan Bead를 이용한 Cd등의 중금속 이온의 흡착제거)

  • 권성환;김기환;장문석;유재근
    • Journal of environmental and Sanitary engineering
    • /
    • v.11 no.3
    • /
    • pp.21-27
    • /
    • 1996
  • Chitosan is a natural polyelectrolytic compound. Researches of adsorption capacity using chitosan have been doing actively. We prepared bead type gel, simple modifier of chitosan, And then experimented adsorption test of heavy metals (Cd etc) using it. According to the result adsorption capacity of chitosan bead was five times higher than chitosan powder. Removal rate of cadmium resulted 90% over in the test that initial concentration of Cd was 100mg/L and bead dosage was 6g/100mL. Adsorption type of heavy metals was similar to general adsorption curve. And optical pH range was 4 - 10 in the adsorption test. In the experiments of other heavy metals (Pb, Zn, Cu, Mn) adsorption types had two stages, highly removal rate-stage at the short time (20minutes) and then slow rate-stage at the after. And removal efficiency at the variable pH ranges revealed relatively good.

  • PDF

A Kinetic Study on the Phosphorus Adsorption by Physical Properties of Activated Carbon (활성탄 물성에 따른 인 흡착의 동력학적 연구)

  • Seo, Jeongbeom;Kang, Joonwon
    • Journal of Korean Society on Water Environment
    • /
    • v.26 no.3
    • /
    • pp.491-496
    • /
    • 2010
  • This study aimed to obtain equilibrium concentration on adsorption removal of phosphorus by activated carbon, to express the adsorption characteristics following Freundlich isotherm and also, based on the value obtained, to investigate the relationship between physical properties of activated carbon and dynamics of phosphorus removal by obtaining rate constant and effective pore diffusivity. The results summarized from this study are as follows. Phosphorus adsorption equilibrium reaching time of powdered activated carbon was reduced as the dosage of activated carbon increases, while granular activated carbon despite increased dosage did not have influence on adsorption equilibrium reaching times of phosphorus as well, taking more than 10 hours. It was also noted that powdered activated carbon showed better adsorption ability than granular activated carbon. The value of constant (f) of Freundlich isotherm of powered activated carbon on phosphorus was 4.26 which is bigger than those of granular activated carbon. The adsorption rate constant on phosphorus of powered activated carbon with low effective diameter and iodine number was highest as $8.888hr^{-1}$ and the effective pore diffusivity ($D_e$) was lowest as $2.45{\times}10^{-5}cm^2/hr$, and the value of phosphorus adsorption rate constant of granular activated carbon was $0.174{\sim}0.372hr^{-1}$, It was revealed that, with the same amount of dosage, the adsorptive power of activated carbon with lower effective diameter was better and its rate constant was also high.

Real Time Control of pH and Dye Adsorption in Acid Dye/Nylon System(II) -Prediction of Dyeing Rate Constant and Dye Adsorption Using a Fuzzy System- (산성염료/Nylon 염색에서 pH와 염료흡착의 실시간 제어(II) -퍼지를 이용한 염색속도 상수와 흡진율 예측-)

  • Hwang, Jee-Sang;Cho, Hyeon-Tae
    • Textile Science and Engineering
    • /
    • v.44 no.1
    • /
    • pp.47-52
    • /
    • 2007
  • A fuzzy system which can predict a dyeing rate constant and maximum adsorption in acid dye/nylon system was studied. In this system, pH control profile constant is an input variable and dyeing rate constant is an output variable and the simplified reasoning for fuzzy inference and gradient descent algorithm for optimizing the fuzzy system are used. The result showed that it is possible to predict dyeing rate constants and maximum adsorption with the online control of dyebath pH in acid dye/nylon dyeing system.

An Experimental Study on the Heat and Mass Transfer of Adsorption Chiller (흡착식 냉동기의 열 및 물질전달에 관한 실험적 연구)

  • Kwon Oh-Kyung;Yun Jae-Ho;Joo Young-Ju;Kim Yong-Chan;Kim Joung-Ha
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
    • /
    • v.17 no.8
    • /
    • pp.746-753
    • /
    • 2005
  • Adsorption chillers have been receiving considerable attentions as they are energy-saving and environmentally benign systems. In order to evaluate adsorption rates, experiments were performed in the batch type adsorption apparatus. Three types of silica gels were investigated under an assortment of experimental conditions that are representatives of the actual operating environments in the adsorber of adsorption chillers. Experimental results revealed the effects of silica gel particle size, bed temperature, and fin pitch of fin tube on the adsorption rate. The $0.25\~1.18mm$ particle size of silica gel with high adsorption rate was selected as a suitable adsorbent. The measured adsorption rate became bigger with decreasing particle size. From the comparison of adsorption rate, it is found that the fin tube has about $21\%$ higher value than that of the bare tube. The effect of heat and mass flux is found to be more significant in the fin tube than in the bare tube.

Adsorption Characteristics of Toluene Vapor in Fixed-bed Activated Carbon Column (고정층 활성탄 흡착반응기에서 기상 톨루엔의 흡착특성)

  • Lim Jin-Kwan;Lee Song-Woo;Kam Sang-Kyu;Lee Dong-Whan;Lee Min-Gyu
    • Journal of Environmental Science International
    • /
    • v.14 no.1
    • /
    • pp.61-69
    • /
    • 2005
  • Adsorption characteristics of toluene vapor, which is one of important source of volatile organic compounds (VOCs), by activated carbon were investigated using a fixed bed adsorption column. The operating parameters such as breakthrough curve, adsorption capacity, mass transfer zone (MTZ), and length of unused bed (LUB) were studied. The experimental results showed that the breakthrough time decreased with increasing inlet toluene concentration and gas flow rate. MTZ and LUB increased with the increase of inlet concentration, gas flow rate, and particle size of activated carbon. The adsorption capacity increased with the increase of inlet toluene concentration, while it decreased with increasing particle size. However, it was kept at constant value regardless of the increase of gas flow rate. Adsorption isotherm of toluene vapor could be represented by the Freundlich adsorption equation fairly well. From the adsorption experiments using some VOC gases such as toluene, xylene, butyl acetate. butanol and acetone, it was also found that the adsorption capacity was higher in the case of gas with higher boiling point and lower vapor pressure.

Comparison of Surface Characteristics and Adsorption Rate of Benzene Vapor According to Modifications of Activated Carbon (개질에 따른 활성탄의 표면특성과 Benzene 증기의 흡착속도 비교)

  • Lee, Song-Woo;Kam, Sang-Kyu;Lee, Min-Gyu
    • Journal of Environmental Science International
    • /
    • v.17 no.8
    • /
    • pp.919-924
    • /
    • 2008
  • The surface properties and adsorption rates of activated carbon modified with acid and base were compared. The distribution ratio of C and C-H on the surface of activated carbon were decreased by modification with acid and base, but the distribution ratio of C-O, C=O, and O=C-O were increased. Base modification damaged the surface of activated carbon more than acid modification, it caused the effect of 6 percent increments of surface area. Adsorption rate model was more suitable to second order equation than first order equation. Adsorption rate was controlled by adsorption in pore better than in surface.

A Study on the comparison on Adsorption characteristics of Zeolite and DETOX for the removal of H2S (H2S 제거를 위한 Zeolite와 DETOX의 흡착 특성 비교 연구)

  • Park, Dae-Seok;Lim, Ji-Young;Cho, Young-Gun;Song, Seung-Jun;Kim, Jin-Han
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.15 no.7
    • /
    • pp.4675-4681
    • /
    • 2014
  • This study examined the $H_2S$ removal characteristics, such as breakthrough time, adsorption capacity, and adsorption rate of adsorbents between Zeolite 3A and DETOX in terms of the $H_2S$ inflow concentration and adsorption temperature. The adsorption capacity of Zeolite 3A increased with increasing mass flow rate of hydrogen sulfide($H_2S$) inflow, but the breakthrough time decreased. On the other hand, both the adsorption capacity and breakthrough time of DETOX decreased with increasing mass flow rate of $H_2S$ inflow. The adsorption capacity and breakthrough time of Zeolite 3A decreased with increasing adsorption temperature but those of DETOX increased. The adsorption capacity of DETOX was higher than that of Zeolite 3A by a factor of 2.5 - 16.4 because the collision frequency that overcomes the activation energy barrier increased with increasing adsorption temperature. For Zeolite 3A and DETOX, the adsorption rate of $H_2S$ increased with increasing mass flow rate of $H_2S$ inflow and adsorption temperature. The adsorption rate of $H_2S$ for Zeolite 3A was 4 times as much as that for DETOX. For the removal of $H_2S$ in biogas, DETOX had an advantage over Zeolite 3A because DETOX had a much longer breakthrough time and greater adsorption capacity in the temperature range of 308~318K than Zeolite 3A.