Adsorption isotherms of N2 and 02 on dealuminated clinoptilolite zeolites were measured by the inverse gas chromatography method at zero-coverage. This type of microporous solids such as natural （CLINA） and dealumin...Adsorption isotherms of N2 and 02 on dealuminated clinoptilolite zeolites were measured by the inverse gas chromatography method at zero-coverage. This type of microporous solids such as natural （CLINA） and dealuminated clinoptilolite zeolites （CLIDA1-CLIDA5） were conditioned by means of acid treatment of the natural zeolitic precursor （CLINA） with HCI at different concentration. Adsorption of selected gases （N2 and 02） on clinoptilolite zeolites were studied in the temperature range from 398 K to 498 K. The Langmuir adsorption model was found to approximately fit the gases adsorption data, within the selected temperature range. The uptake amount of these gases by the diverse adsorbents was temperature dependent. Additionally, the energies of interaction between of these gases with clinoptilolite microporous walls were realized from the evaluation of the isosteric heats of adsorption （qst）. These isosteric heats were found to obey in the following decreasing order： qst （N2）： CLIDA1 〉 CLIDA3 〉 CLIDA2 〉 CLIDA4 〉 CLIDA5 〉 CLINA; while qst （02）： CLIDA3 〉 CLIDA2 〉 CL1DA1 〉 CLIDA5 〉 CLIDA4 〉 CLINA.展开更多
Coconut-based activated carbons were modified with sodium dodecyl sulfate (SDS). The activated carbons, which were modified by different concentrations of SDS, were characterized by acid/base titrations, textural anal...Coconut-based activated carbons were modified with sodium dodecyl sulfate (SDS). The activated carbons, which were modified by different concentrations of SDS, were characterized by acid/base titrations, textural analysis (BET), atomic absorption spectrochemical analysis and Zeta potential measurements. The effects of SDS modification on Pb2+ absorption were studied further. The results indicate that after the modification of SDS, there are new functional groups on the surface of modified activated carbons and the number of functional group has changed remarkably, the total acidity decreases observably, but the total alkalinity increases dramatically. With the increase of surface load with SDS, the Pb2+ adsorption mass of activated carbons increases and the optimal pH for Pb2+ adsorption of the SDS modified activated carbons is 5. The experimental data are simulated better by Freundlich isotherm model for the modified activated carbons, and the experimental data are simulated better by Langmuir isotherm model for unmodified ones.展开更多
文摘Adsorption isotherms of N2 and 02 on dealuminated clinoptilolite zeolites were measured by the inverse gas chromatography method at zero-coverage. This type of microporous solids such as natural （CLINA） and dealuminated clinoptilolite zeolites （CLIDA1-CLIDA5） were conditioned by means of acid treatment of the natural zeolitic precursor （CLINA） with HCI at different concentration. Adsorption of selected gases （N2 and 02） on clinoptilolite zeolites were studied in the temperature range from 398 K to 498 K. The Langmuir adsorption model was found to approximately fit the gases adsorption data, within the selected temperature range. The uptake amount of these gases by the diverse adsorbents was temperature dependent. Additionally, the energies of interaction between of these gases with clinoptilolite microporous walls were realized from the evaluation of the isosteric heats of adsorption （qst）. These isosteric heats were found to obey in the following decreasing order： qst （N2）： CLIDA1 〉 CLIDA3 〉 CLIDA2 〉 CLIDA4 〉 CLIDA5 〉 CLINA; while qst （02）： CLIDA3 〉 CLIDA2 〉 CL1DA1 〉 CLIDA5 〉 CLIDA4 〉 CLINA.
基金Project(2007AA06Z121) supported by the National High Technology Research and Development Program of ChinaProject(50774095) supported by the National Natural Science Foundation of ChinaProject(CL12111) supported by the Undergraduate Innovation Experimentation Plan of Central South University,China
文摘Coconut-based activated carbons were modified with sodium dodecyl sulfate (SDS). The activated carbons, which were modified by different concentrations of SDS, were characterized by acid/base titrations, textural analysis (BET), atomic absorption spectrochemical analysis and Zeta potential measurements. The effects of SDS modification on Pb2+ absorption were studied further. The results indicate that after the modification of SDS, there are new functional groups on the surface of modified activated carbons and the number of functional group has changed remarkably, the total acidity decreases observably, but the total alkalinity increases dramatically. With the increase of surface load with SDS, the Pb2+ adsorption mass of activated carbons increases and the optimal pH for Pb2+ adsorption of the SDS modified activated carbons is 5. The experimental data are simulated better by Freundlich isotherm model for the modified activated carbons, and the experimental data are simulated better by Langmuir isotherm model for unmodified ones.
