2019 Vol. 4, No. 1

Cover info & Content
Editorial
Abstract:
Review article
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Li–O2 batteries have attracted much attention because of their high specific energy. However, safety problem generated mainly from the flammable organic liquid electrolytes have hindered the commercial use of Li–O2 batteries. One of the competitive alternatives is polymer electrolytes due to their flexibility and non-flammable property. Moreover, the hybrid polymer electrolyte with enhanced electrochemical properties would be achieved by incorporating inorganic filler, liquid plasticizer and redox mediator into the polymer. While most researches of the hybrid polymer electrolyte focused on Li-ion batteries, few of them took account into its application in Li–O2 batteries. In this review, we mainly discuss hybrid polymer electrolytes for Li–O2 batteries with different composition. The critical issues including conductivity and stability of electrolytes are also discussed in detail. Our review provides some insights of hybrid polymer electrolytes for Li–O2 batteries and offers necessary guidelines for designing the suitable hybrid polymer electrolyte for Li–O2 batteries as well.
Short Review
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Typically, a Lewis acid and a Lewis base can react with each other and form a classical Lewis adduct. The neutralization reaction can however be prevented by ligating the acid and base with bulky substituents and the resulting complex is known as a “frustrated Lewis pair” (FLP). Since the Lewis acid and base reactivity remains in the formed complex, FLPs can display interesting chemical activities, with promising applications in catalysis. For example, FLPs were shown to function as the first metal-free catalyst for molecular hydrogen activation. This, and other recent applications of FLPs, have opened a new thriving research field. In this short-review, we recapitulate the computational and experimental studies of the H2 activation by FLPs. We discuss the thus-far uncovered mechanistic aspects, including pre-organization of FLPs, the reaction paths for the activation, the polarization of HH bond and other factors affecting the reactivity. We aim to provide a rather complete mechanistic picture of the H2 activation by FLPs, which has been under debate for decades since the first discovery of FLPs. This review is meant as a starting point for future studies and a guideline for industrial applications.
Abstract:
Heap bioleaching is one of the most clean and economical processes for recovery of low-grade and complex ores, because the sulfide minerals are natural habitats for acidophiles capable of iron- and sulfur-oxidation. The most exciting advances in heap bioleaching are occurring in the field of microbiology, especially with the development of advanced molecular biology approaches. These chemolithotrophic microorganisms living in the acid mine environment fix N 2 and CO2 and obtain energy for growth from soluble ferrous iron and reduced inorganic sulfur compounds during oxidation of sulfide minerals. The ferric iron as oxidant and sulfuric acid are a result of microbial activity and provide favorable conditions for the dissolution of sulfide minerals. Various microbial consortia were applied successfully in commercial bioleaching heaps around the world, and microbial community and activity were adapted related to the local climatic conditions, ore characteristics and engineering configuration. This review focuses on diversity of bioleaching microbes, their role in heap bioleaching processes, their community structure and function in industrial heaps and the relation to the ore characteristics and the engineering configuration, to give implications for optimizing leaching efficiency of heap bioleaching.
Research paper
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A comparative study of the extractive desulfurization (EDS) mechanism by Cu(II) and Zn-based ILs ([C4mim]2[MCl4], M = Cu(II) or Zn) has been performed. It is found that the π–π interaction and C-H⋯π interaction play important roles in EDS for both Cu(II) and Zn-based ILs, which is different from Al, Fe-based ILs. In the gas phase models, the interaction energy between Zn-based ILs and dibenzothiophene (DBT) is stronger than the interaction energy of Cu(II)-based ILs. In order to consider the solvent effect, a generic ionic liquid of solvation model has been implemented, which is few considered in the previous calculations of EDS. It is interesting to find that the gap of interaction energies between Cu(II), Zn-based ILs and DBT are reduced when the solvent effect is considered. In addition, by combined discussion of currently theoretical and experimental evidences for metal-based ILs with different compositions, we firstly propose that the EDS performance should be influenced by the balance of the contribution of cation, metal-based anion, metal chlorides and the viscosity.
Abstract:
Novel superacid SO4H-functionalized ionic liquids (SFILs) were designed and prepared in this work. The catalytic activities of SFILs were evaluated in xylan hydrolysis and xylose dehydration to produce furfural. Combined with the results of acid strength of SFILs characterized by solid-state 31P MAS NMR, it was found that the catalytic performance of SFILs was positively correlated to their acid strength. The superacid SFIL [Ch-SO4H][CF3SO3] displayed the best catalytic performance with more than 80% yield of furfural, and it was also obviously superior to usual SO3H-functionalized acidic ILs, mineral liquid acids, and acidic resin Amberlyst-15 catalysts in catalytic activity under optimized conditions. In addition, the superacid SFIL [Ch-SO4H][CF3SO3] could be easily separated from reaction system and reused at least five times without obvious decrease.
Abstract:
Decorative wood panels containing pouches of bio-based phase changing materials (PCMs) were prepared. Three different PCM mixtures were used: a blend of capric and lauric acids as well as two commercial products, Puretemp®20 and Puretemp®23 (Puretemp). The panels consist of engraved Medium Density Fiberboard (MDF) filled with a plastic pouch filled with PCM. High density fiberboard (HDF) was used on top of the panels to enclose the PCM pouches. PCM mixtures were first tested by differential scanning calorimetry (DSC). Phase change temperature and total heat storage of the panels were measured for both fusion and solidification with a Dynamic Heat-Flow Meter Apparatus (DHFMA). DSC and DHFMA results were compared, allowing a better understanding of results gathered from these two techniques. DSC calibration has been revealed important when assessing PCMs. The panels present a phase change temperature and a latent heat storage suitable for buildings applications. The panel made with Puretemp®23 presented the highest energy, with 57.1 J g−1. Thermal cycling was conducted on the panels to investigate thermal reliability, which revealed small modifications of thermal properties for two products. For all cases, latent heat was found stable. Hygro-mechanical behavior of the panels was also evaluated as these where designed to be esthetic decorative panels. This study exposes the potential of a new type of wood-based panels loaded with PCM for thermal energy storage and brings overall knowledge about PCM products thermal characterization.
Abstract:
It is essential to prepare highly-efficiency reproducible adsorbent for purifying industrial dye wastewater. In this work, biscuit with a layered porous structure as a template is applied to prepare a photocatalytic recyclable adsorbent of BiFeO3/Carbon nanocomposites for purifying simulative industrial dye wastewater. It is found that the structure of the prepared BiFeO3/Carbon nanocomposite is related to the natural structure of the biscuit, annealing temperatures and immersing times, demonstrated by XRD, TEM, UV-Vis and adsorptive activities. Kinetics data shows that the adsorption rate of the adsorbent to the dye is rapid and fitted well with the pseudo-second-order model, that more than 80% of dyes can be removed in the beginning 30 min. The adsorption isotherm can be perfectly described by the Langmuir model as well. It can be seen from the adsorption data that the adsorption performance can reach over 90% at pH = 2–12, which can imply its universal utilization. The prepared BiFeO3/Carbon nanocomposites have also displayed excellent capacities (over 90% within 30 min) for adsorption of seven different dyes and their mixed one. According to the five times photocatalytic reproducible experiments, it is proved that BiFeO3/Carbon nanocomposites show the excellent stability and reproduction for purifying simulative industrial dyes, even the sample have been placed for one year. These research results indicate that the adsorbent BiFeO3/Carbon can be a suitable material used in treating industrial dye wastewater potentially.
Abstract:
In this work, nickel metal supported on different supports (SiO2, Al2O3, ZSM-5) were prepared by spraying nickel nitrate on the supports and calcined at 873 K. Then, they were characterized by XRD, XRF, N2 adsorption–desorption, NH3-TPD, MCH-TPD, H2-TPR, and pyridine-FTIR, and tested as catalysts for the dehydrogenation aromatization and isomerization of methylcyclohexane (MCH) under the conditions of S-Zorb catalytic adsorption desulfurization (T = 673 K, P = 1.5 MPa, WHSV = 5 h−1). The H2-TPR results showed that the interaction of NiO with support decreased in the order of NiO/ZSM-5-Fe < NiO/ZSM-5 < NiO/Al2O3 < NiO/SiO2. The decrease of the interaction appeared to facilitate the reduction of Ni and therefore to promote the dehydrogenation aromatization of MCH. It was found that a direct correlation existed between the gasoline components yields, cracking activity and the total number of different supports acid sites measured by NH3-TPD tests. Higher total acidity of ZSM-5 resulted in gasoline loss because of higher cracking activity of MCH. The number of total acid sites of NiO/ZSM-5-Fe decreased and the medium strong Brönsted acid sites necessary for MCH isomerization increased after the modification of ZSM-5 by iron metal. So, NiO/ZSM-5-Fe exhibited enhanced MCH conversion, aromatic and isomerization yields when compared to NiO/ZSM-5 and other Ni-based catalysts. This study shows that NiO/ZSM-5-Fe catalyst may be possible to be integrated into the S-Zorb system achieving the recovery of the octane number of gasoline.
Abstract:
Coprocessing of bitumen-derived feeds and biomass through a fluid catalytic cracking (FCC) route has the potential to assist in the reduction of fuel and petroleum product carbon footprints while meeting government regulatory requirements on renewable transportation fuels. This approach is desirable because green house gas (GHG) emissions for producing renewable biofuels are significantly lower than those for fossil fuels, and coprocessing can be executed using existing refining infrastructure to save capital cost. The present study investigates the specific FCC performances of pure heavy gas oil (HGO) derived from oil sands synthetic crude, and a mixture of 15 v% canola oil in HGO using a commercial equilibrium catalyst under typical FCC conditions. Cracking experiments were performed using a bench-scale Advanced Cracking Evaluation (ACE) unit at fixed weight hourly space velocity (WHSV) of 8 h−1, 490–530 °C, and catalyst/oil ratios of 4–12 g/g. This work focuses on some cracking phenomena resulting from the presence of oxygen in the blend—a lower heat requirement for cracking due to the exothermic water formation, which also entails lower hydrogen yield at a given severity. The distribution of feed oxygen in gaseous and liquid products, the mitigation in GHG emissions, and the technological and economical advantages of the coprocessing option are also discussed.