Carbon nanotube architectures as catalyst supports for proton exchange membrane fuel cells

Catalyst support materials exhibit great influence on the performance and durability of proton exchange membrane (PEM) fuel cells. This minireview article summarises recent developments into carbon nanotube-based support materials for PEM fuel cells, including the membrane electrode assembly (MEA). The advantages of using CNTs to promote catalyst performance and stability, a perspective on research directions and strategies to improve fuel cell performance and durability are discussed. It is hoped that this minireview will act as a conduit for future developments in catalyst supports and MEA design for PEM fuel cells.

Evaluation of pre-treatments for minimizing membrane fouling in water recovery

 RO membrane major foulants were reviewed. Among available pre-treatment technologies four pre-treatments namely; MF, UF, MBR membranes and GMF are qualitatively ranked as best. Further, experiments and fouling mathematical models showed suitability of UF and MF membrane as pre-treatments, based on their higher permeability and lower fouling potentiality than others.

Highly stable external short-circuit-assisted oxygen ionic transport membrane reactor for carbon dioxide reduction coupled with methane partial oxidation

A membrane reactor allows for simultaneous separation and reaction, and thus, can play a good role to produce value-added chemicals. In this work, we demonstrated such a membrane reactor based on fluorite oxide samarium-doped ceria (SDC) using an external short-circuit concept for oxygen permeation. The fluorite phase was employed to impart its high structural stability, while its limited electronic conductivity was overcome by the application of an external short circuit to function the SDC membrane for oxygen transport. On one side of the membrane, i.e., feed side, carbon dioxide decomposition into carbon monoxide and oxygen was carried out with the aid of a Pt or Ag catalyst. The resultant oxygen was concurrently depleted on the membrane surface and transported to the other side of the membrane, favorably shifting this equilibrium-limited reaction to the product side. The transported oxygen on the permeate side with the aid of a GdNi/Al2O3 catalyst was then consumed by the reaction with methane to form syngas, i.e., carbon monoxide and hydrogen. As such, the required driving force for gas transport through the membrane can be sustained by coupling two different reactions in one membrane reactor, whose stability to withstand these different gases at high temperatures is attained in this paper. We also examined the effect of the membrane thickness, oxygen ionic transport rate, and CO2 and CH4 flow rates to the membrane reactor performance. More importantly, here, we proved the feasibility of a highly stable membrane reactor based on an external short circuit as evidenced by achieving the constant performance in CO selectivity, CH4 conversion, CO2 conversion, and O2 flux during 100 h of operation and unaltered membrane structure after this operation together with the coking resistance.

Relationship between membrane fatty acids and cognitive symptoms and information processing in individuals at ultra-high risk for psychosis

Cognitive symptoms and impairment are central to schizophrenia and often an early sign of this condition. The present study investigated biological correlates of cognitive symptoms and performance in individuals at ultra-high risk (UHR) for psychosis. The study sample comprised 80 neuroleptic-naïve UHR individuals aged 13-25 years. Associations among erythrocyte membrane fatty acid levels, measured by gas chromatography, and cognitive functioning were investigated in UHR patients. Subjects were divided into terciles based on their scores on the cognitive factor of the Positive and Negative Syndrome Scale. The Zahlen-Verbindungs Test (ZVT) (the number-combination test) was also used as a measure of information-processing speed. Exploratory analysis was conducted to investigate the relationship between membrane fatty acid levels with the size of the intracranial area (ICA), a neurodevelopmental measure relevant to schizophrenia, in half of subjects (n=40) using magnetic resonance imaging. The adjusted analysis revealed that omega-9 eicosenoic and erucic acid levels were significantly higher, but omega-3 docosahexaenoic acid levels were significantly lower, in the cognitively impaired than in the cognitively intact group. We found a significant negative association of eicosenoic, erucic, and gamma-linoleic acids with ZVT scores. A negative association between ICA and membrane levels of eicosenoic acid was also found. This is the first study to demonstrate the relationship between membrane fatty acids and cognitive function in neuroleptic-naïve subjects at UHR for psychosis. The study findings indicate that abnormalities in membrane fatty acids may be associated with the neurodevelopmental disruption associated with the cognitive impairments of individuals at UHR for psychosis.