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A novel pyrimidine-bridged organoalkoxysilane precursor, 4,6-bis(3-triethoxysilyl-1-propoxy)-1,3-pyrimidine (BTPP), was synthesized via a platinum-catalyzed reaction and subsequently a BTPP membrane was developed via a sol-gel process. This new membrane exhibits great potential for improved CO 2 separation compared with common amine-functionalized organosilica membranes. Possible CO 2 transport mechanisms across amine-functionalized organosilica membranes were explored by comparing the CO 2 sorption behaviors of organoalkoxysilane materials with both strong and mild affinities. The results showed that a membrane with strong affinity to CO 2 does not lead to a superior CO 2 separation capability. Hence, the concept of a “mild-affinity membrane” was proposed, which describes membranes with intermediate-to-low CO 2 binding energy that exhibits an improved level of CO 2 transport efficiency. The concept of a mild-affinity membrane offers the development of technological innovation leading to the realization of highly efficient CO 2 separation membranes. [ABSTRACT FROM AUTHOR]

[Display omitted] • A comprehensive study of naphtha separation by a series of adsorbents. • Influence of pore structure on the separation of real naphtha mixtures. • Influence of separation mechanism on the separation of naphtha mixtures. Naphtha separation is of significant importance for refineries to make full use of oil and to reduce the cost of refining. In the recent years, scientists have devoted great efforts to developing novel porous materials such as metal-organic frameworks (MOFs) for the separation of naphtha. However, previous investigations have been limited to single-component or 3- to 5-component model systems. Separation of full range hydrocarbon mixture such as naphtha has rarely been explored. In this work, we carry out a comprehensive study on the separation of alkane isomers as well as full range naphtha mixture by a series of robust microporous MOFs, e.g., Zr-abtc, Al-bttotb, Co-fa, in comparison with representative zeolite materials, e.g., ZSM-5 and zeolite 5A. We find that Al-bttotb and Co-fa, which can separate monobranched and dibranched alkanes through complete molecular exclusion, show superior separation performance for naphtha mixtures. This work may shed light on strategies for developing adsorbents with optimal performance for naphtha separation and ultimately realizing the industrialization of MOF-based separation technologies. [ABSTRACT FROM AUTHOR]

[Display omitted] • C 2 H 4 /C 2 H 6 separation was studied using highly permeable ZIF-8 membranes. • The membrane temperatures were varied from −30 to 100 °C for separation. • A high C 2 H 4 permeance of 8.1 × 10−7 mol/(m2·s·Pa) was observed at −30 °C. Ethylene/ethane separation is a critical and energy-consuming process in the chemical industry due to the similar properties of the compounds and the great need of ethylene for e.g., polymer production. Many materials have been studied for their implementation as membranes as an energetically favorable alternative to conventional distillation and adsorption processes. Metal-organic frameworks (MOF) have revealed promising properties as highly permeable and selective membranes. Among the most studied and promising MOF candidates is ZIF-8, known for its thermal stability and small pores connected by narrow-sized windows. In this work, we present an analysis of the influence of parameters such as temperature, feed pressure and feed flowrate on the separation of ethylene/ethane through a thin ZIF-8/alumina disc membrane. We observed that the temperature has a significant effect on the separation. The ethylene permeance increased with decreased temperature and reached 8.1 × 10−7 mol/(m2·s·Pa) at −30 °C. At this temperature, the ethylene/ethane selectivity was 2.5. The study concluded with a considerable enhancement of the permeance of ZIF-8 membranes for ethylene/ethane separations, while maintaining a good selectivity compared to the reported values in the literature. The results have important implications for the development of more cost-effective and energy-efficient membrane-based separation technologies for ethylene purification. [ABSTRACT FROM AUTHOR]