An exciting opportunity for zeolite adsorbent design in separation of C4 olefins through adsorptive separation

Effective C4 Separation by Zeolite Metal-Organic Framework Composite Membranes

Inorganic zeolites have excellent molecular sieving properties, but they are difficult to process into macroscopic structures. In this work, we use metal-organic framework (MOF) glass as substrates to engineer the interface with inorganic zeolites, and then assemble the discrete crystalline zeolite powders into monolithic structures. The zeolites are well dispersed and stabilized within the MOF glass matrix, and the monolith has satisfactory mechanical stabilities for membrane applications. We demonstrate the effective separation performance of the membrane for 1,3-butadiene (C4H6) from other C4 hydrocarbons, which is a crucial and challenging separation in the chemical industry. The membrane achieves a high permeance of C4H6 (693.00±21.83 GPU) and a high selectivity over n-butene, n-butane, isobutene, and isobutane (9.72, 9.94, 10.31, and 11.94, respectively). This strategy opens up new possibilities for developing advanced membrane materials for difficult hydrocarbon separations.

A comprehensive review on nanocatalysts and nanobiocatalysts for biodiesel production in Indonesia, Malaysia, Brazil and USA

Biodiesel is an alternative to fossil-derived diesel with similar properties and several environmental benefits. Biodiesel production using conventional catalysts such as homogeneous, heterogeneous, or enzymatic catalysts faces a problem regarding catalysts deactivation after repeated reaction cycles. Heterogeneous nanocatalysts and nanobiocatalysts (enzymes) have shown better advantages due to higher activity, recyclability, larger surface area, and improved active sites. Despite a large number of studies on this subject, there are still challenges regarding its stability, recyclability, and scale-up processes for biodiesel production. Therefore, the purpose of this study is to review current modifications and role of nanocatalysts and nanobiocatalysts and also to observe effect of various parameters on biodiesel production. Nanocatalysts and nanobiocatalysts demonstrate long-term stability due to strong Brønsted-Lewis acidity, larger active spots and better accessibility leading to enhancethe biodiesel production. Incorporation of metal supporting positively contributes to shorten the reaction time and enhance the longer reusability. Furthermore, proper operating parameters play a vital role to optimize the biodiesel productivity in the commercial scale process due to higher conversion, yield and selectivity with the lower process cost. This article also analyses the relationship between different types of feedstocks towards the quality and quantity of biodiesel production. Crude palm oil is convinced as the most prospective and promising feedstock due to massive production, low cost, and easily available. It also evaluates key factors and technologies for biodiesel production in Indonesia, Malaysia, Brazil, and the USA as the biggest biodiesel production supply.

Zeolites in Adsorption Processes: State of the Art and Future Prospects

Zeolites have been widely used as catalysts, ion exchangers, and adsorbents since their industrial breakthrough in the 1950s and continue to be state-of the-art adsorbents in many separation processes. Furthermore, their properties make them materials of choice for developing and emerging separation applications. The aim of this review is to put into context the relevance of zeolites and their use and prospects in adsorption technology. It has been divided into three different sections, i.e., zeolites, adsorption on nanoporous materials, and chemical separations by zeolites. In the first section, zeolites are explained in terms of their structure, composition, preparation, and properties, and a brief review of their applications is given. In the second section, the fundamentals of adsorption science are presented, with special attention to its industrial application and our case of interest, which is adsorption on zeolites. Finally, the state-of-the-art relevant separations related to chemical and energy production, in which zeolites have a practical or potential applicability, are presented. The replacement of some of the current separation methods by optimized adsorption processes using zeolites could mean an improvement in terms of sustainability and energy savings. Different separation mechanisms and the underlying adsorption properties that make zeolites interesting for these applications are discussed.

Finned hierarchical MOFs supported on cellulose for the selective adsorption of n-hexane and 1-hexene

Finned hierarchical MOF particles (Cu(BDC) nanosheets as fins grown perpendicularly on Ni₂(BDC)₂(DABCO) hexagonal prisms) were synthesized on modified cellulose support. The hierarchical MOF particles exposed the open Cu(II) sites on Cu(BDC) to enable selective 1-hexene/n-hexane separation.

Recent progress in environmental applications of metal-organic frameworks

Nanomaterials have aroused the interest of many researchers and become a research hotspot in recent years and metal-organic frameworks (MOFs) included in that are a class of new organic-inorganic hybrid porous materials formed through the self-assembly of organic ligands and inorganic metal ions. MOFs have been attracting increasing attention due to their structural diversification, large specific surface area, high porosity, inerratic pore space framework. These characteristics play their advantages in different fields and make some excellent achievements. This article summarizes the research progress of metal-organic framework in the field of environment especially the remarkable achievements in adsorption and provides a clear help for understanding the research progress and prospects for future research.

Comparative study on different strategies for synthesizing all-silica DD3R zeolite crystals with a uniform morphology and size

In the last three decades, the all-silica deca-dodecasil 3R (DD3R) zeolite has been extensively studied as a significant potential class of porous materials in adsorptive separations. However, the use of most existing synthesis methods is unable to produce pure DD3R crystals with a uniform morphology and size. The present research, is therefore intended to provide a facile protocol to synthesize pure DD3R crystals with a controllable morphology and size and with a high reproducibility and productivity. Special attention was focused on investigating the effects of the type of seeds and the mineralizing reagent on the phase-purity, morphology, and crystal size of the resultant DD3R crystals. Various techniques, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), N₂ adsorption–desorption at 77 K, and thermogravimetric analysis (TGA) were then used to characterize the synthesized samples. The results show that by adding a small amount of “amorphous” DD3R or “amorphous” ZSM-58 seeds, the pure DD3R crystals with a uniform morphology and size can be synthesized using 1-adamantanamine (1-ADA) as a structure-directing agent (SDA), KF was used as a mineralizing reagent, and LUDOX AS-30 as a silicon source at 443 K for 1 d. In addition, the pure, large and uniform hexahedron DD3R crystals can be prepared using fumed silica as seeds, although the crystallization time takes a longer period of 3 d. The present work could stimulate fundamental research and industrial applications of the all-silica DD3R zeolite.

A facile protocol was developed to synthesize pure DD3R crystals with a controllable morphology and size, as well as high reproducibility and productivity.