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adsorption isotherms AND POTENTIAL DISTRIBUTIONS OF NITROGEN ON VARIOUS ACTIVATED CARBONS

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Chinese Journal of Reactive Polymers 2005年第1期14卷 8-13页

作者： LI Xiang LI Zhong LUO lingai Chemistry Department of Zhaoqing University Zhaoqing 526061 China The Institute of Chemical Engineering South China University of Technology Guangzhou 510640 China Locie Esigec-Universitéde Savoie Campus Scientifique Savoie Technolac 73376 Le Bourget-Du-Lac cedex France

The adsorption isotherms of four activated carbons （Norit Rill, Chemviron BPL, Monolit, and Ambersorb-572） have been examined by nitrogen adsorption at 77.5 K. A method for adsorption potential distribution calculation has been proposed based on the adsorption isotherms. This distribution provides information about possible changes in the Gibbs free energy caused by the energetic and geometrical heterogeneities of an activated carbon as well as by the adsorbate-related entropic effects. The general character of the adsorption potential distribution is clearly visible by its simple relation to the micropore and mesopore distribution,

关键词： adsorption isotherms adsorption potential distributions Micropore Structure Structural heterogeneity.

Kinetics and isotherms of Neutral Red adsorption on peanut husk

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Journal of Environmental Sciences 2008年第9期20卷 1035-1041页

作者： HAN Runping HAN Pan CAI Zhaohui ZHAO Zhenhui TANG Mingsheng Department of Chemistry Zhengzhou University Zhengzhou 450052 China China Petroleum and Chemical Corporation Luoyang Company Luoyang 471012 China

adsorption of Neutral Red (NR) onto peanut husk in aqueous solutions was investigated at 295 K. Experiments were carried out as function of pH, adsorbent dosage, contact time, and initial concentration. The equilibrium adsorption data were analyzed by Langmuir, Freundlich, Temkin, Dubinin-Radushkevich, and Toth isotherm models. The results indicated that the Toth and Langmuir models provided the best correlation of the experimental data. The adsorption capacity of peanut husk for the removal of NR was deter...

关键词： peanut husk Neutral Red adsorption isotherms kinetics

Enhanced adsorption of Methylene Blue from aqueous solution by chitosan-g-poly(acrylic acid)/vermiculite hydrogel composites

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Journal of Environmental Sciences 2010年第4期22卷 486-493页

作者： Yi Liu Yian Zheng Aiqin Wang Center of Eco-material and Green Chemistry Lanzhou Institute of Chemical Physics Chinese Academy of Sciences Lanzhou 730000 China Graduate University of the Chinese Academy of Sciences Beijing 100049 China

A series of chitosan-g-poly （acrylic acid）/vermiculite hydrogel composites were synthesized and used as adsorbents for the investigation of the effect of process parameters such as vermiculite content, pH of dye solution, contact time, initial concentration of dye solution, temperature, ionic strength and concentration of surfactant sodium dodecyl sulfate on the removal of Methylene Blue （MB） from aqueous solution. The results showed that the adsorption capacity for dye increased with increasing pH, contact time and initial dye concentration, but decreased with increasing temperature, ionic strength and sodium dodecyl sulfate concentration in the present of the surfactant. The adsorption kinetics of MB onto the hydrogel composite followed pseudo second-order kinetics and the adsorption equilibrium data obeyed Langmuir isotherm. By introducing 10 wt.% vermiculite into chitosan-g-poly （acrylic acid） polymeric network, the obtaining hydrogel composite showed the highest adsorption capacity for MB, and then could be regarded as a potential adsorbent for cationic dye removal in a wastewater treatment process.

关键词： hydrogel composites vermiculite Methylene Blue adsorption kinetics adsorption isotherms

Pb(Ⅱ) removal from water using Fe-coated bamboo charcoal with the assistance of microwaves

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Journal of Environmental Sciences 2013年第5期25卷 1044-1053页

作者： Zengsheng Zhang Xuejiang Wang Yin Wang Siqing Xia Ling Chen Yalei Zhang Jianfu Zhao State Key Laboratory of Pollution Control and Resources Reuse College of Environmental Science and EngineeringTongji University

Bamboo charcoal（BC） was used as starting material to prepare iron-modified bamboo charcoal（Fe-MBC） by its impregnation in FeCl 3 and HNO 3 solutions simultaneously,followed by microwave *** material can be used as an adsorbent for Pb（Ⅱ） contaminants removal in *** composites were prepared with Fe molar concentration of 0.5,1.0 and 2.0 mol/L and characterized by means of N 2 adsorption-desorption isotherms,X-ray diffraction spectroscopy（XRD）,scanning electron microscopy coupled with energy dispersive X-ray spectrometry（SEM-EDS）,Fourier transform infrared（FT-IR） and point of zero charge（pH pzc） *** adsorption analyses showed that the BET specific surface area and total pore volume increased with iron *** adsorbent with Fe molar concentration of 2 mol/L（2Fe-MBC） exhibited the highest surface area and produced the best pore *** Pb（Ⅱ） adsorption process of 2Fe-MBC and BC were evaluated in batch experiments and 2Fe-MBC showed an excellent adsorption capability for removal Pb（Ⅱ）.The adsorption of Pb（Ⅱ） strongly depended on solution pH,with maximum values at pH *** ionic strength had a significant effect on the adsorption at pH 〈 *** adsorption isotherms followed the Langmuir isotherm model well,and the maximum adsorption capacity for Pb（Ⅱ） was 200.38 mg/g for *** adsorption processes were well fitted by a pseudo second-order kinetic *** parameters showed that the adsorption of Pb（Ⅱ） onto Fe-MBC was feasible,spontaneous,and exothermic under the studied conditions,and the ion exchange mechanism played an significant *** results have important implications for the design of low-cost and effective adsorbents in the removal of Pb（Ⅱ） from wastewater.

关键词： adsorption bamboo charcoal microwave assistance kinetics adsorption isotherms

Relationship between breakthrough curve and adsorption isotherm of Ca(Ⅱ)imprinted chitosan microspheres for metal adsorption

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Chinese Journal of Chemical Engineering 2016年第2期24卷 323-329页

作者： Yangcheng Lu Jing He Longwen Wu Guangsheng Luo State Key Laboratory of Chemical Engineering Department of Chernical Engineering Tsinghua UniversityBeijing 100084China State Key Laboratory of New Ceramics and Fine Processing School of Materials Sdence and EngineeringTsinghua UniversityBeijing 100084China

In this work, an equilibrium-dispersion model was successfully established to describe the breakthrough performance of Ca（Ⅱ） imprinted chitosan （Ca（Ⅱ）-CS） microspheres packed column for metal adsorption, and the assumptions of Langmuir isotherms and axial dispersion controlled mass transfer process were confirmed. The axial dispersion coefficient in Ca（Ⅱ）-CS microspheres packed column was found to be almost proportional to the linear velocity and fit for prediction through single breakthrough test. Sensitivity analysis for breakthrough curve indicated the axial dispersion coefficient as well as Langmuir coefficient was sensitive variable for deep removal requirement. The retrieval of the adsorption isotherms of Ca（Ⅱ）-CS microspheres from breakthrough curve was fulfilled by modelling calibration. A strategy based on the correlation between adsorption isotherms and breakthrough performance was further proposed to simplify the column adsorption design using absorbents with small/uniform size and fast adsorption kinetics like Ca（Ⅱ）-CS microspheres to cut down the gap between lab and industry.

关键词： Correlation Breakthrough curve adsorption isotherms Metal adsorption Ca(ll)-imprinted chitosan microsphere

adsorption of Methylene Blue on magnesium silicate: Kinetics, equilibria and comparison with other adsorbents

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Journal of Environmental Sciences 2010年第3期22卷 467-473页

作者： Franco Ferrero Department of Materials Science and Chemical Engineering Polytechnic of Torino Corso Duca degli Abruzzi 24 I10129 Torino Italy

Batch adsorption from aqueous solutions in a slightly basic medium of Methylene Blue, up to 2500 mg/L, onto synthetic magnesium silicate （Florisil） of three particle size ranges （mean diameters of 112, 200 and 425 μm） was compared to the corresponding adsorption onto activated carbon and Amberlite XAD-2. The best fit of the kinetic results was achieved by a pseudo second-order equation. The equilibrium data were found to be well represented by the Langmuir isotherm equation. Amberlite XAD-2, an unspecific adsorbent capable of adsorbing exclusively through a surface effect, exhibited a poor dye uptake, confirming that the adsorption mechanism on Florisil was due to electrostatic attraction and ion exchange. Moreover, the comparison between Florisil and the other adsorbents was performed on the basis of the evaluation of the surface area and pore volume occupied by the adsorbed dye.

关键词： dye adsorption magnesium silicate Florisil adsorption kinetics adsorption isotherms

adsorption of dimethyl trisulfide from aqueous solution on a low-cost adsorbent:thermally activated pinecone

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Chinese Journal of Oceanology and Limnology 2015年第1期33卷 169-175页

作者：商景阁何伟范成新 Department of Environmental Science China Pharmaceutical University State Key Laboratory of Lake Science and Environment Nanjing Institute of Geography and LimnologyChinese Academy of Sciences Shanghai Investigation and Design and Research Institute

Thermally activated pinecone(TAP) was used for the adsorption of dimethyl trisulfide(DMTS)from aqueous solutions,which was proved to be the main odorous in algae-caused black *** effects of adsorbent dosage,adsorbate concentration and contact time on DMTS biosorption were *** TAP produced at 600℃ exhibited a relatively high surface area(519.69 m^2/g) and excellent adsorption *** results show that the adsorption of DMTS was initially fast and that the equilibrium time was6 *** initial DMTS concentrations led to lower removal percentages but higher adsorption *** removal percentage of DMTS increased and the adsorption capacity of TAP decreased with an increase in adsorbent *** adsorption process conforms well to a pseudo-second-order kinetics *** adsorption of DMTS is more appropriately described by the Freundlich isotherm(R^2=0.996 1) than by the Langmuir isotherm(R^2=0.916 9).The results demonstrate that TAP could be an attractive low-cost adsorbent for removing DMTS from water.

关键词： dimethyl trisulfide low-cost adsorption isotherms adsorbent

Mechanisms and factors affecting the adsorption of sodium alginate onto modified clays

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Chinese Journal of Oceanology and Limnology 2013年第4期31卷 867-875页

作者：林勇新曹西华宋秀贤王楠俞志明 Key Laboratory of Marine Ecology and Environmental Sciences Institute of OceanologyChinese Academy of Sciences University of Chinese Academy of Sciences

Algal organic materials （AOMs） are one critical factor affecting the efficiency of modified clays used for the mitigation of harrnful algal blooms （HABs）. This study was conducted to develop a deeper understanding of the mechanisms and factors affecting the adsorption of AOMs onto modified clays. Sodium alginate （polysaccharide） and kaolinite modified with polyaluminium chloride （PAC1） were used as AOMs and modified clay model substances, respectively, and the effects of modifier dosage, contact time, solution pH and ionic strength were investigated through batch adsorption experiments. Kinetics revealed that the alginate adsorption rate was described well by a pseudo-second order model. PACl effectively enhanced the adsorption capacity of kaolinite and increased the adsorption rate, and the optimum additive amount of PACl was 5%. The experimental data fitted both the Freundlich and Langmuir adsorption equations well. The adsorption thermodynamics for alginate onto modified clays suggests that alginate adsorption is a spontaneous process. The adsorption of alginate onto modified clays was highly dependent on pH, with a decrease in adsorption observed with increased pH to 9.48, but the opposite was true above pH 9.48. Finally, adsorption increased with increasing ionic strength.

关键词： modified clays sodium alginate adsorption kinetics adsorption isotherms pH ionic strength

Activated Sericite:An Efficient and Effective Natural Clay Material for Attenuation of Cesium from Aquatic Environment

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Pedosphere 2014年第6期24卷 731-742页

作者： D.TIWARI LALHMUNSIAMA S.I.CHOI S.M.LEE Department of Chemistry School of Physical SciencesMizoram University Department of Health and Environment Kwandong University Department of Environmental Engineering Kwangwoon University

Sericite is mica-based natural clay that is annealed at 800 ℃ for 4 h, followed by acid activation using 3.0 mol L-1HCl at 100℃. The interaction of cesium(I), Cs(I), with sericite could provide useful data for the study of soil erosion or mass water movement utilizing the natural radioactive Cs. In this study sericite and activated sericite were used to assess their suitability in the attenuation of Cs from the aquatic environment under both batch and column experiments. The surface morphological studies indicated that a disordered and heterogeneous surface structure was exhibited by the activated sericite, whereas the native sericite exhibited a compact and layered structure. The Brunauer-Emmett-Teller(BET) specific surface area results indicated a significant increase in the surface area due to the activation of sericite. The batch reactor data collected for various parametric studies revealed that an increase in p H(from 2.0 to 8.0) and sorbate concentration(from 10.0 to 100.0 mg L-1) apparently favored the attenuation of Cs(I). The timedependent sorption data revealed that Cs(I) uptake was very rapid, and it achieved its saturation value within just 50 min of *** kinetic modeling studies indicated that the uptake of Cs(I) followed a pseudo-second-order rate equation; hence, the attenuation capacity of these solids for Cs(I) was estimated to be 0.858 and 4.353 mg g-1for sericite and activated sericite solids, *** adsorption isotherm modeling data showed a reasonably good applicability of the Freundlich model than the Langmuir *** effect of background electrolyte concentrations(0.001 to 0.1 mol L-1) of Mg(NO3)2indicated that the presence of this electrolyte could not significantly affect the percent removal of Cs(I) by activated sericite. Furthermore, the fixed-bed column reactor operations were performed to obtain the breakthrough data, which were fitted well to the Thomas non-linear equation. Therefore, the loading capacity of Cs(I) wa

关键词： adsorption isotherms breakthrough data electrolyte kinetics radionuclide