Thesis (Ph. D.)--Lehigh University, 1999. / Includes vita. Includes bibliographical references (leaves 248-262).

Thesis (Ph.D.) -- McMaster University, 1997. / Includes bibliographical references Also available via World Wide Web.

Palladium membranes have been identified as the membranes of choice in hydrogen separation and purification processes due to their infinite selectivity to hydrogen when defect free. Despite their potentials in hydrogen processes, palladium membranes pose challenges in terms of cost and embritllement which occurs when palladium comes in contact with hydrogen at temperatures below 573 K. The challenges posed by palladium membranes have encouraged research into nonpalladium based membranes such as Silica and Alumina. This thesis investigates hydrogen permeation and separation in palladium membranes and also the use of nonpalladium membranes, Silica and Alumina membranes in hydrogen permeation. In this study, hydrogen permeation behavior was investigated for 3 types of membranes, Palladium, Silica and Alumina. Thin palladium films were deposited onto a 30 nm porous ceramic alumina support using both conventional and modified electroless plating methods. The hydrogen separation and purification behavior of the membranes were investigated including the effect of annealing at higher temperatures. Gas permeation through Silica and Alumina membranes was investigated for 5 single gases including hydrogen. The Silica and Alumina membranes were fabricated using the dip coating method and their hydrogen permeation behavior of investigated at different coatings. A thin Palladium (Pd1) membrane with a thickness of 2 μm was prepared over porous ceramic alumina support using the electroless plating method and a maximum hydrogen flux of 80.4 cm3 cm-2 min-1 was observed at 873 K and 0.4 bar after annealing the membrane. The hydrogen flux increased to 94.5 cm3 cm-2 min-1 at same temperature and pressure for the Palladium membrane (Pd2) prepared using the modified electroless plating method. The hydrogen flux increased to 98.1 cm3 cm2 min-1 for the palladium/silver (Pd/Ag) membrane prepared using the codeposition electroless plating method and the PdAg membrane avoided the hydrogen embrittlement at low temperature. Hydrogen purity for the membrane was also investigated for a reformate gas mixture and a maximum hydrogen purity of 99.93% was observed at 873 K and 0.4 bar. The hydrogen purity was observed to increase as a result of the addition of sulphur which surpresses the inhibition effect of the carbon monoxide in the reformate gas mixture. The presence of CO and CO2 was observed to lead to an increase of the exponential factor n above 0.5 as a result of the inhibiting effect of these compounds on hydrogen permeation. The value of the exponential factor n depicting the rate limiting step to hydrogen permeation in the palladium and palladium-alloy membranes was also investigated. Deviations from Sievert’s law were observed from the Palladium membranes inverstigated in this work. In single gas hydrogen permeation investigation for the Pd1 membrane prepared using the conventional electroless plating method, the value of the exponential factor n = 0.5 in accordance with Sievert’s law. However, for the mixed gas hydrogen separation investigation n=0.62 at 573 K which decreased to 0.55 when the membrane was annealed at 873 K. For the Pd2 membrane prepared using the modified elctroless plating method, n=1 at 573 K but the value decreased to 0.76 for the mixed gas hydrogen separation investigation at same temperature which depicts a deviation from Sievert’s law. In all the investigations carried out for the Pd3 palladium alloy membrane prepared using the co-deposition Pd/Ag electroless plating method at same conditions with the Pd1 and Pd2 membranes, n=0.5 in accordance with Sievert’s law. For the Nonpalladium based Silica and ceramic Alumina membranes, investigations were carried out for hydrogen permeation and 5 other single gases; He, CO2, CH4, N2 and Ar. For the Silica membranes, a maximum hydrogen permeance of 3.12-7 x 10 mol m-2 s-1 Pa-1 at 573 K and 0.4 bar was observed which increased to 4.05 x 10-7 mol m-2 s-1 Pa-1 at 573 K and 0.4 when the membrane was modified with Boehmite sol prior to deposition of the Silica layer. The permeance for hydrogen and the 5 single gases was investigated for the alumina membrane at 5 successive coatings. It was observed that the commercial alumina membrane displayed a maximum hydrogen permeance of 9.72 x 10-7 mol m-2 s-1 Pa-1 at 573 K and 0.4 bar which increased to 9.85 x 10-7 mol m-2 s-1 Pa-1 at same temperature and pressure when the membrane was modified with Boehmite sol.

Recent developments have confirmed that in the future hydrogen demand in industrial applications will arise because of the growing requirements for H2 in chemical manufacturing, petroleum refining, and the newly emerging clean energy concepts. Hydrogen is mainly produced from the steam reforming of natural gas and water gas shift reactions. The major products of these processes are hydrogen and carbon dioxide. The selective removal of CO2 from the product gas is important because it poisons catalysts in the reactor and it is highly corrosive. Membrane separation processes for hydrogen purification may be employed as alternative for conventional methods such as adsorption, cryogenic distillation. Mixed matrix membranes (MMMs) are composed of an insoluble phase dispersed homogeneously in a continuous polymer matrix. They have potential in gas separation applications by combining the advantageous properties of both phases. The objective of this study is to produce neat polybenzimidazole (PBI) membranes and PBI based mixed matrix membranes for separation of H2/CO2. Furthermore, to test the gas permeation performance of the prepared membranes at permeation temperatures of 35oC to 90oC. Commercial PBI supplied from both Celanese and FumaTech were used as polymer matrix. PBI was selected based on its thermal, chemical stabilities and mechanical properties and its performance as a fuel-cell membrane produced by PBI. Micro-sized Zeolite 3A and nano-sized SAPO-34 are zeolites with 0.30 nm and 0.38 nm pore size respectively have attracted considerable interest and employed as fillers in this study. Commercial Zeolite 3A and synthesized SAPO-34 by our group was used throughout the study. Membranes were prepared using N,N-dimethylacetamide as the solvent. Prepared membranes were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). The effect of annealing procedure and operating temperature on gas separation performance of resultant neat PBI, PBI/Zeolite 3A and PBI/SAPO-34 membranes were investigated by gas permeation tests. Hydrogen and carbon dioxide gases were used for single gas permeation measurements. Two different annealing strategies were utilized namely in-line annealing and in-oven annealing. In-oven annealing was performed in an oven in nitrogen atmosphere at 120oC, 0.7 atm while in-line annealing was performed in the gas permeation set-up by feeding helium as permeating gas at 90oC and 3 bar. Neat PBI and PBI/ Zeolite 3A membranes were in-oven annealed. The in-oven annealed membranes showed better selectivities with lower permeabilities, but the performance results of these membranes had low repeatability. On the other hand, in-line annealed membranes showed much higher permeabilities and lower selectivities with stable performance. By changing the annealing method hydrogen permeability increased from 5.16 Barrer to almost 7.77 barrer for neat membranes and for PBI/Zeolite 3A mixed matrix membranes increased from 5.55 to to 7.69 Barrer at 35oC. The selectivities were decreased from 6.21 to 2.31 for neat membranes and for PBI/Zeolite 3A from 5.55 to 2.63. Effect of increasing operating temperature was investigated by using in-line annealed membranes. Increasing temperature from 35oC to 90o improved the performance of the both types of membranes and repeatable results were obtained. Besides neat PBI and PBI/Zeolite 3A, PBI/SAPO-34 membranes were prepared only via in-line annealing. The addition of nano-sized filer to the membranes provided homogeneous distribution in polymer matrix for PBI/SAPO-34 membranes. For this type of membrane hydrogen permeability increased from 8.01 to 26.73 Barrer and with no change in H2/CO2 selectivities via rising temperature. Consequently, it is better to study hydrogen and carbon dioxide separation at high temperature. For all types of membranes hydrogen showed higher activation energies. In between all membranes magnitude of activation energies were the highest for PBI/SAPO-34 membrane which is an indication of good interaction between polymer and zeolite interface. In-line annealed membranes gave the best gas permeation results by providing repeatability of measurements. Among all studied membranes in-line annealed PBI/SAPO-34 membrane exhibited the best gas permeation results.

Thesis (Ph.D.)--University of Waikato, 2006. / Includes bibliographical references (leaves [186]-203) Also available via the World Wide Web.

No description available.

A exploração de petróleo é uma das mais importantes atividades industriais da sociedade moderna e seus derivados tem inúmeras aplicações em relação processos industriais.A água que é separada do petróleo é chamada água de produção de petróleo. A composição da água de produção de petróleo é muito complexa, sendo a alta salinidade sua característica marcante podendo chegar a 120 g .L-1. em cloretos. Devido ao volume e a complexidade da água de produção de petróleo o seu tratamento é um grande problema para as indústrias petrolíferas. Neste trabalho foi possível concluir que a combinação das técnicas de coagulação/floculação, microfiltração e processos oxidativos avançados (TiO2/UV/H2O2) foi eficiente para a remoção de fenol da água de produção de petróleo. Na etapa de coagulação/floculação o tempo de repouso, a interação entre o agente coagulante e o pH assim como a interação dos três parâmetros analisados foi estatisticamente significativa para remoção de turbidez considerando um grau de 95% de confiança. Nesta etapa a maior redução de turbidez foi obtida utilizando PAC como agente coagulante em pH 3 e tempo de repouso da amostra de 10 min. A seqüência de tratamentos proposta (coagulação/floculação; membranas; POAs) não se mostrou economicamente viável devido à necessidade de remoção do TiO2 no final do processo. / Oil exploration is one of the most important industrial activities of modern society and their products have numerous applications in industrials process. The water that is separated from oil production is called produced water. The composition of this water is very complex, high salinity and phenol are it principal characteristic, chlorides may reach 120 g.L-1. Due to the volume and complexity of the produced water it treatment is the major problem of the oil industries. In this study it was concluded that the combination of the techniques of coagulation / flocculation, microfiltration and advanced oxidation processes (TiO2/UV/H2O2) was efficient for phenol removal. During the coagulation / flocculation step, the rest time, the interaction between coagulant agent and pH as well as the interaction of the three analyzed parameters was significant for turbidity removal considering a 95% of confidence. At this stage the greatest reduction of turbidity was obtained using PAC as coagulant agent at pH 3 and 10 minutes sample of rest time. The proposed treatment sequence (coagulation / flocculation; membranes; AOPs) was not economically viable due to necessity of TiO2 removal at the end of the process.

A exploração de petróleo é uma das mais importantes atividades industriais da sociedade moderna e seus derivados tem inúmeras aplicações em relação processos industriais.A água que é separada do petróleo é chamada água de produção de petróleo. A composição da água de produção de petróleo é muito complexa, sendo a alta salinidade sua característica marcante podendo chegar a 120 g .L-1. em cloretos. Devido ao volume e a complexidade da água de produção de petróleo o seu tratamento é um grande problema para as indústrias petrolíferas. Neste trabalho foi possível concluir que a combinação das técnicas de coagulação/floculação, microfiltração e processos oxidativos avançados (TiO2/UV/H2O2) foi eficiente para a remoção de fenol da água de produção de petróleo. Na etapa de coagulação/floculação o tempo de repouso, a interação entre o agente coagulante e o pH assim como a interação dos três parâmetros analisados foi estatisticamente significativa para remoção de turbidez considerando um grau de 95% de confiança. Nesta etapa a maior redução de turbidez foi obtida utilizando PAC como agente coagulante em pH 3 e tempo de repouso da amostra de 10 min. A seqüência de tratamentos proposta (coagulação/floculação; membranas; POAs) não se mostrou economicamente viável devido à necessidade de remoção do TiO2 no final do processo. / Oil exploration is one of the most important industrial activities of modern society and their products have numerous applications in industrials process. The water that is separated from oil production is called produced water. The composition of this water is very complex, high salinity and phenol are it principal characteristic, chlorides may reach 120 g.L-1. Due to the volume and complexity of the produced water it treatment is the major problem of the oil industries. In this study it was concluded that the combination of the techniques of coagulation / flocculation, microfiltration and advanced oxidation processes (TiO2/UV/H2O2) was efficient for phenol removal. During the coagulation / flocculation step, the rest time, the interaction between coagulant agent and pH as well as the interaction of the three analyzed parameters was significant for turbidity removal considering a 95% of confidence. At this stage the greatest reduction of turbidity was obtained using PAC as coagulant agent at pH 3 and 10 minutes sample of rest time. The proposed treatment sequence (coagulation / flocculation; membranes; AOPs) was not economically viable due to necessity of TiO2 removal at the end of the process.

Poly(ether-b-amide) (Pebax® grade 1074) is a waterproof breathable block copolymer containing soft poly(ethylene oxide) and rigid polyamide 12 segments. Its intrinsic gas permeabilities to nitrogen, oxygen, methane, helium, hydrogen, and carbon dioxide were tested under different feed pressures (0.3 – 2.5 MPa) and temperatures (20 – 80 °C). This helps to obtain a comprehensive understanding of the polymer, because prior work reported in the literature addressed only a few gases and used inconsistent membrane preparation and test methods. Relatively high polar (or quadrupolar)/nonpolar gas selectivity were observed. CO2/N2 selectivity was demonstrated to be as high as 105±0.4 in Pebax®1074, with CO2 permeability coefficient of approximately 180±1 Barrer at room temperature. Additionally, the effects of solvent used in membrane preparation, heat treatment, membrane thickness, and polymer solution concentration on the membrane permeability were evaluated. Pebax® is a highly breathable material, thus its application as breathable chemically-resistant protective clothing was studied. Dimethyl methylphosphonate (DMMP) – a sarin simulant – was selected as the challenge agent. The liquid pervaporation of pure water (simulating perspiration) and pure DMMP were measured for Pebax®1074, Pebax®2533, nitrile, latex, poly(vinyl chloride), low density polyethylene, silicone, and silicone-polycarbonate copolymer under pervaporation mode. Pebax®1074 was not only the most water permeable material but also the most selective of all the tested materials for water/DMMP – making it a very promising material for this application.

Poly(ether-b-amide) (Pebax® grade 1074) is a waterproof breathable block copolymer containing soft poly(ethylene oxide) and rigid polyamide 12 segments. Its intrinsic gas permeabilities to nitrogen, oxygen, methane, helium, hydrogen, and carbon dioxide were tested under different feed pressures (0.3 – 2.5 MPa) and temperatures (20 – 80 °C). This helps to obtain a comprehensive understanding of the polymer, because prior work reported in the literature addressed only a few gases and used inconsistent membrane preparation and test methods. Relatively high polar (or quadrupolar)/nonpolar gas selectivity were observed. CO2/N2 selectivity was demonstrated to be as high as 105±0.4 in Pebax®1074, with CO2 permeability coefficient of approximately 180±1 Barrer at room temperature. Additionally, the effects of solvent used in membrane preparation, heat treatment, membrane thickness, and polymer solution concentration on the membrane permeability were evaluated. Pebax® is a highly breathable material, thus its application as breathable chemically-resistant protective clothing was studied. Dimethyl methylphosphonate (DMMP) – a sarin simulant – was selected as the challenge agent. The liquid pervaporation of pure water (simulating perspiration) and pure DMMP were measured for Pebax®1074, Pebax®2533, nitrile, latex, poly(vinyl chloride), low density polyethylene, silicone, and silicone-polycarbonate copolymer under pervaporation mode. Pebax®1074 was not only the most water permeable material but also the most selective of all the tested materials for water/DMMP – making it a very promising material for this application.