Institutional Repository of Institute of Process Engineering, CAS (IPE-IR）
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State Key Joint Laboratory of Environmental Simulation and Pollution Control[22Y01SSPCP]
No full textBed hydrodynamics of a new three-phase fluidized bed flotation column with steel ball particles
No full textThe new three-phase fluidized bed flotation column (TFC) hydrodynamics characteristics, such as gas holdup, bubble diameter and bubble surface area flux have been carried out, and this study focuses on bed fluid hydrodynamic parameters of the TFC. The bed hydrodynamic characteristics viz., bed fluctuation ratio (r), bed expansion ratio (R) and bed voidage (epsilon) of the TFC have been studied using air as the discontinuous phase and water as the continuous phase, respectively. The effects of the system parameters studied include superficial gas, liquid velocities and initial static bed height (H-0). Experimental studies based on the Response surface methodology (RSM) have been made to investigate the mathematical model of hydrodynamic parameters (r, R, epsilon) and bubble diameter (D-b) of the TFC. The results show that the models which were established by operating variables can predict the r, R, epsilon and D-b of the TFC well. Based on the previous investigation of the optimization of bubble performance parameters which has been caned out by Liu et al. (2020), the correlation of D-b has been carried out, and the result shows that H-0 is the boundary condition that determines the variation of D-b. The optimization of D-b by RSM shows that relatively small bubbles can be obtained when H-0 is greater than 0.290 m within the range of parameters studied. The values of the experiment have been compared with those predicted by the proposed models and have been found to agree well
Adsorption mechanism of yttrium ions onto ion-adsorption type rare earths ore
No full textIon-adsorption type rare earths ore, as the primary source for middle-heavy rare earth elements, was extracted by various electrolytes via the adsorption-desorption effect. In this work, adsorption behavior and mechanism for yttrium ions onto ion-adsorption type rare earths ore as adsorbents were investigated systematically and comprehensively. The isotherms and kinetics suggested the adsorption of yttrium ions was consistent to Langmuir and pseudo-second-order model, revealing that the adsorption process was homogeneous and primarily governed by chemical adsorption. Maximum adsorption capacity could attain as 4.45 mg.g(-1) in pH of 3 with 10 g.L-1 yttrium ions. Moreover, thermodynamics analysis indicated the adsorption process was spontaneous, and random. ATR-FTIR, XPS and DFT results indicated that Y(III) adsorbed onto ion-adsorption type rare earths ore surface possibly via Si-O-Y bond
Multifunctional polyzwitterion ionic liquid coating for long-lifespan and dendrite-free Zn metal anodes
No full textAqueous zinc (Zn) metal batteries have received widespread attention due to their high safety and environmental friendliness. However, the uncontrollable growth of dendrites, hydrogen evolution reaction, and corrosion severely limit the practical application of aqueous Zn batteries. Herein, a multifunctional water-blocking polyzwitterion ionic liquid coating poly([2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)-co-tert-butyl acrylate) as the protective layer of the Zn metal anode is proposed to solve these issues. The water-blocking tert-butyl acrylate can prevent water molecules from contacting the Zn metal anode, which plays a key role in inhibiting the hydrogen evolution reaction and corrosion. Meanwhile, zwitterionic ionic liquid moieties are able to tune the solvation environment of the Zn2+ at the electrode/electrolyte interface, inducing compact and planar deposition of the Zn metal. With this synergy effect, the assembled Zn//Zn and Zn//Cu cells achieve a long-term stable plating/stripping performance over 2500 h and a high average coulombic efficiency of 98.6% for 1500 cycles. The Zn//MnO2 and Zn//Mg0.1V2O5 center dot H2O full cells show negligible capacity decay (0.005%) after 4500 cycles. This work provides a new opportunity to protect Zn anodes by water-blocking polyzwitterion ionic liquid coatings in the aqueous electrolyte
Fischer-Helferich glycosidation mechanism of glucose to methyl glycosides over Al-based catalysts in alcoholic media
No full textThe Fischer-Helferich glycosidation reaction is generally the initial step in the conversion of glucose to levulinate in alcohol media. However, the relevant molecular mechanism catalyzed by Al-based catalysts is still not well understood. In this work, the reaction mechanism of the glycosidation from glucose to methyl glycosides catalyzed by Al3+ coordinated with methanol/methoxyl was investigated through density functional theory (DFT) calculations. The whole reaction process includes ring-opening, addition, and ring-closure events. The addition of methanol to the ring-opening structure of glucose makes the electronegativity of C1 site stronger to proceed with the following ring-closure reaction. Among the 28 kinds of ways of ring-closure reaction, the most preferred way is to close the loop through the six-membered ring (O5-C1) to generate methyl glucoside (MDGP). The rate-determining step is the ring-closure and the Al3+ shows a great catalytic effect which is mainly reflected in coordinating with the solvents to transfer protons. The results would be helpful to understanding the Fischer-Helferich glycosidation mechanism catalyzed by Al-based catalysts and comprehend the conversion of glucose to high value-added chemicals
In situ discovery on the formation of supported silver catalysts for ethylene epoxidation
No full textSilver particles supported on alumina are the main industrial catalysts for ethylene epoxidation. Silver catalysts are usually produced by an impregnation method followed by thermal decomposition. Although the decomposition process determines the structures and properties of silver catalysts, we are short of information on this high temperature process. Herein we employed a confocal laser scanning microscope (CLSM) equipped with a heating stage to disclose the thermal decomposition process of silver precursor towards the preparation of high selective silver catalysts. It is found that the formation of silver catalysts experiences two steps: crystallization and decomposition. The crystallization occurs at the tem-perature below 80celcius, resulting in the formation of silver complex. Further heating the sample to 140celcius, leads to the formation of silver particles at alumina wafers. The atmosphere has a significant effect on the formation and performance of catalysts. When the samples are heated in the nitrogen, small silver particles with similar size are formed, which leads to a high selectivity of ethylene epoxidation. The role of thermal atmospheres on the size and property of silver catalysts is discussed in this paper.(c) 2022 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved
Progress of CCUS technology in the iron and steel industry and the suggestion of the integrated application schemes for China
No full textThe iron and steel industry is a dominant carbon emission source in China. CCUS is an important potential technology for large-scale carbon reduction. However, due to the characteristics of multi-point source emissions of the iron and steel industry, the application is still in its infancy. Here, the research progresses of CCUS technology in the iron and steel industry are systematically reviewed, including the projects and novel materials. The maturity and applicability of various technologies were further analyzed by considering the CO2 emission characteristics of different steel-making processes. Finally, four kinds of integrated schemes of CCUS in the iron and steel industry were proposed, including "synergistic chemical utilization of hydrogen resource and CO2", "steel slag mineralization and carbon fixation in coordination with solid waste disposal", "microalgae biological carbon fixation collaborative wastewater treatment", and "CO2 geological utilization and storage". The applicability of the proposed integrated schemes were further analyzed based on the regional distribution of iron and steel enterprises in China. The results of this work were aimed at facilitating the application of CCUS in the iron and steel industry in China