MOR/DEA/TEA mixed-template synthesis of CHA-type SAPO with different silica and alumina sources

We investigated the effects of different sources of alumina (Pseudo-boehmite, Aluminum hydroxide, Aluminum tri-sec-butylate, Aluminum isopropoxide, and Aluminum phosphate) and silica (Silica sol, Silicic acid, Tetraethyl orthosilicate, and sodium silicate)...

Comparative Synthesis and Characterization of Nanostructured SAPO-34 Using TEA and Morpholine: Effect of Mono vs. Dual Template on Catalytic Properties and Performance toward Methanol to Light Olefins

Aim and Objective: Production of light olefins from methanol was studied over SAPO-34 molecular sieves exploring the effect of mono and dual templates. Herein, the single templates of TEA, morpholine and mixed template of TEA/morpholine (equal molar ratio of TEA and morpholine) were used to synthesize SAPO-34 catalysts. Materials and Methods: The prepared samples were prepared via hydrothermal synthesis method and characterized with XRD, FESEM, PSD, EDX, BET and FTIR techniques. Results: It was found that the crystallinity decreased upon applying TEA as template and also it can be noted that the intensity of the SAPO-34 phase peaks increased by increasing the morpholine in template mixture. Production of much smoother particles for the catalyst synthesized with binary template mixture of TEA/morpholine can be depended on the crystallinity increase. Si incorporation value was decreased for the catalyst with a major phase of SAPO-5 (topological structure of AFI). It is indicative that the TEA application would facilitate the formation of AFI structure which is incapable of the incorporating higher amounts of Si in to the crystallite framework. Conclusion: The nature of the template determines the morphology of final product due to different rate of crystal growth obtained in accordance with XRD and FESEM results. Therefore, the catalyst synthesized with TEA/morpholine mixture shows the best performance among synthesized samples in terms of life time in the MTO process sustaining light olefins selectivity at higher values (about 90% after 630 min TOS).

Understanding PCR Processes to Draw Meaningful Conclusions from Environmental DNA Studies

ABSTRACTAs environmental DNA (eDNA) studies have grown in popularity for use in ecological applications, it has become clear that their results differ in significant ways from those of traditional, non-PCR-based surveys. In general, eDNA studies that rely on amplicon sequencing may detect hundreds of species present in a sampled environment, but the resulting species composition can be idiosyncratic, reflecting species’ true biomass abundances poorly or not at all. Here, we use a set of simulations to develop a mechanistic understanding of the processes leading to the kinds of results common in mixed-template PCR-based (metabarcoding) studies. In particular, we focus on the effects of PCR cycle number and primer amplification efficiency on the results of diversity metrics in sequencing studies. We then show that proportional indices of amplicon reads capture trends in taxon biomass with high accuracy, particularly where amplification efficiency is high (median correlation up to 0.97). Our results explain much of the observed behavior of PCR-based studies, and lead to recommendations for best practices in the field.

Ruthenium decorated hierarchically ordered macro–mesoporous carbon for lithium oxygen batteries

A ruthenium-decorated hierarchically ordered macro–mesoporous carbon (MmC@Ru) obtainedviaa mixed template method exhibits excellent electrochemical performance for lithium oxygen batteries.

Investigating the mixing sequence and the Si content in SAPO-34 synthesis for selective conversion of methanol to light olefins using morpholine &/ TEAOH templates

SAPO-34 as the commercialized catalyst of methanol to olefin (MTO) process was synthesized by single and mixed-template methods using TEAOH and morpholine. The mixing sequence in gel preparation and the optimum Si content were investigated.