AN ABSTRACT OF THE DISSERTATION OF DINESH SINGH RAWAT, for the Doctor of Philosophy degree in APPLIED PHYSICS, presented on July 6 2009, at Southern Illinois University Carbondale. TITLE: STUDY OF GAS ADSORPTION ON AS-PRODUCED AND MODIFIED CARBON NANOTUBES MAJOR PROFESSOR: Dr. Aldo D. Migone Volumetric adsorption isotherm measurements were used to study the adsorption characteristics of Ethane (C2H6) and Butane (C4H10) on as-produced single-walled carbon nanotubes. The binding energy of the adsorbed alkane molecule was found to increase with increasing carbon chain length. Two adsorption substeps were obtained for each alkane molecule. However, the size of the high pressure substep was found to be gradually smearing with the increase in size of the adsorbed molecule. This phenomenon is interpreted as size entropy effect for linear molecules. This interpretation was also verified by determining the specific surface area of the substrate using linear molecules of different sizes. Kinetics measurements of alkane adsorption on SWNTs were also conducted and their dependence on the molecular length was determined. Similar adsorption measurements were performed for Argon (Ar) on as-produced single-walled carbon nanotubes and nanotubes that were structurally modified using acid treatment. Enhancement of the sorptive capacity and the presence of two distinct kinetics of gas adsorption verified partial opening of single walled carbon nanotubes as a result of chemical treatment. Mutiwalled carbon nanotubes were exposed to oxygen plasma treatment for varying time periods. Afterwards, adsorption measurements of Methane (CH4) were conducted on untreated and oxygen plasma treated tubes. The presence of an additional substep, after exposing multiwalled carbon nanotubes to oxygen plasma for varying time periods, suggested progressive cleaning of nanotube surface.

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Thesis (Masters Degree (Chemical Engineering)) - Cape Technikon, Cape Town, 1996 / With the increasing awareness ofpreserving the environment, the need for other lixiviants in leaching processes has escalated. The investigation for lixiviants, especially for gold, has entailed mostly the halogen group. From halogens, iodine forms the most stable gold complex. The aim ofthis study was to investigate the adsorption characteristics of gold-iodide onto a coconut shell based activated carbon. In the first part of this study, the factors influencing the adsorption kinetics and equilibrium were investigated. Mixing experiments and interruption tests indicated clearly that the principal adsorption mechanism is by first order film diffusion. When the initial gold concentration was changed, the adsorption kinetics and equilibrium decrease viith an increase in gold concentration. This is due to the shielding effect by the adsorbed gold as it is partly reduced on the carbon surface. The concentration of iodide increased the adsorption kinetics and equilibrium. The increase in concentration of iodine leads to an increase in concentration ofthe principal oxidising agent, tri-iodide, thereby decreasing the adsorption parameters as the gold gets redissolved from the carbon surface. Furthermore, iodine and trio-iodide adsorbs competitively, thereby decreasing the rate ofadsorption ofthe gold complex. This is further iterated by experiments where the carbon was pre-treated v.ith a iodine/iodide solution. In acidic solutions, none, or a minimal amount ofthe gold is red11ced on the carbon surface, adsorption is only in the complex form, while in a alkaline solution, the gold is partly adsorbed and partly reduced. In the second section, the adsorption is approached from a basic electrochemical perspective. Here, depending on the pH ofthe solution, it is shown that the potential ofthe solution dictates the species of iodine and gold-iodide complex in solution, it affects the adsorption characteristics ofthe activated carbon.

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As the worldwide energy demand continues to increase, scientists and engineers are faced with the increasingly difficult task of meeting these needs. Currently, the major energy sources, consisting of oil, coal, and natural gas, are non-renewable, contribute to climate change, and are rapidly depleting. Renewable technology research has become a major focus to provide energy alternatives which are environmentally-friendly and economically competitive to sustain the future worldwide needs. Thermal energy storage using adsorption is a promising technology which can provide energy for heating and cooling applications using solar and waste heat sources. The current work aims to improve adsorption systems to provide higher energy outputs and therefore, more economical systems. New adsorbents and operating conditions were tested with the goal of storing the available energy more efficiently. A model was also developed to gain a better understanding of the adsorption system to improve this developing technology.

Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第15392号 / 工博第3271号 / 新制||工||1492(附属図書館) / 27870 / 京都大学大学院工学研究科物質エネルギー化学専攻 / (主査)教授 垣内 隆, 教授 江口 浩一, 教授 安部 武志 / 学位規則第4条第1項該当

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1. The apparatus used in this investigation is fully described, and a new method is outlined for the calibration of bridge resistances "in situ". 2. A chart is given for the accurate correction of weights in air to weights in vacuum for a range of temperatures extending from 10° to 28°C, and for pressures from 690 to 730 mm. 3. An automatic recycling still has been designed for the continuous production of "ultra-pure" water. This still is capable of delivering daily, in routine operation, 16 l. of water of conductivity less than 100 nm/cm after aeration with "C0₂- and NH₃-free" air. 4. A very soluble layer appears to form on the surface of' glass when it is dried; this layer is readily removed on contact with water. 5. The removal of carbon dioxide and of ammonia from aqueous solution by aeration with an indifferent gas has been fully investigated, and it has been shown that these gases can be completely eliminated by such a process. Whereas the carbon dioxide is removed fairly rapidly, however, the ammonia, whether present alone or together with carbon dioxide, only goes out of solution rather slowly. 6. It has been shown that ammonia is adsorbed from aqueous solution on the glass walls of the cell. 7. There does not appear to be any ammonium bicarbonate in the residual impurity left in the "ultra-pure" water obtained from the still; the impurity can, in fact, be regarded as neutral salt with sufficient accuracy for most purposes. 8. The resistance change which accompanies any variation in the rate of bubbling of the stirring gas through the water has been investigated, but no solution has been found as to the cause of this change. 9. A comparison has been made of the efficiency of different gases for stirring purposes, and it seems that, for general work, nitrogen is by far the most suitable of the common gases. 10. The extrapolation to be used for converting resistances to their values at infinite frequency appears ...