TiO2/Fe2O3 nanocomposites with different morphologies were prepared by precipitation separation method combined with sol?gel method using Fe(NO3)3?9H2O and tetrabutyl titanate as iron and titanium sources, and HF, HAc, NH4F, NH3?H2O, H2O2 as morphology control agents, respectively. The structure and morphology of the TiO2/Fe2O3 samples were characterized by X?ray powder diffraction (XRD) and field emission scanning electron microscope (FESEM), and the degradation performance of the TiO2/Fe2O3 nanocomposites for methylene blue under UV?light irradiation condition was investigated. The results show that the NH3?H2O?TiO2/Fe2O3 nanocomposites prepared with NH3?H2O as the morphology control agent have the best degradation effect on MB, with a degradation rate of 82.9%, which is approximately 1.00, 1.10, 1.14, 1.15, 1.56, 3.57, 12.95 times larger than that of HF?TiO2/Fe2O3 (82.5%), H2O2?TiO2/Fe2O3 (75.7%), NH4F?TiO2/Fe2O3 (72.9%), HAc?TiO2/Fe2O3 (71.8%), TiO2 (53.1%), Fe2O3 (23.1%) and blank (6.4%) samples, respectively. This is attributed to the synergistic effect of its large specific surface area, spindle morphology, highest crystallinity and suitable heterojunction structure.
The effects of polymerization reaction temperature, polymerization reaction time, catalyst and crosslinker addition on the properties of modified ethylene tar pitch (METP) were investigated, and the optimal reaction conditions were obtained by combining elemental analysis, FT?IR, XRD, Raman and thermogravimetric analysis on ETP and METP: The polymerization reaction temperature was 370 ℃, and the polymerization reaction time was 6 h, besides the addition of catalyst and crosslinker was 1.50%. The softening point (SP) of METP obtained under these conditions was 182 ℃, the coking value (CV) was 57.66%, the β resin was 42.26%, and the quinoline insoluble matter (QI) was 0.87%, which met the requirements of high carbon material precursors； The yieid of METP was 73.26%.
UiO?66 has the high specific surface area and porosity, which was selected as a carrier in this study. The impregnation method by loading nano?metal Cu particles was used to prepare the composite catalyst UiO?66/Cu. X?ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and other methods were carried out to characterize the prepared catalysts. Different loads and dosages catalytic effects in catalytic reduction were investigated in this study. The concentration of p?nitrophenol was 5×10-5 mol/L and the dosage of UiO?66/Cu?10 was 10 mg/L, which were the optimal solutions for catalytic effect. Catalytic reduction efficiency of p?nitrophenol could reach more than 97.0% in 5 minutes.
Due to the high storage capacity and multiple electron?transfer chemistry of sulfur (S), Li?S battery with virtues of high theoretical capacity/energy density, eco?friendliness and abundant supply has been considered as one of the most promising candidates for next?generation battery systems. The capacity of Li?S battery is much higher than that of traditional metal oxide cathode?based lithium?ion battery, which is regarded as the highest capacity of solid?state cathode?materials at current stage. As a vital component of Li?S battery, separator plays a profound role in resolving crucial issues (e.g., shuttling effect, volume expansion, poor conductivity and metal dendrites, etc.) of Li?S battery. So far, some pioneering works have been reported in the exploration of separators for Li?S battery. On this basis, covalent organic frameworks (COFs), possessing the advantages of low density, high porosity, well?defined structure, designable structure and functions, is a kind of potential materials for the functional modification of Li?S battery separators. This review will summarize the reported works about COFs in Li?S battery separators including their structural characteristics, preparation?methods, application forms and battery properties. It will also provide a brief perspective for the applications of COFs in Li?S battery separators and hope that it might give new insights for scientists in related fields.
In recent years, the rapid expansion of industries such as new energy has significantly heightened the demand for lithium resources. China boasts ample lithium reserves; however, 80% of these reserves are concentrated in salt lake brine, and the high magnesium?to?lithium ratio inherent in salt lakes poses challenges for lithium extraction. To ensure a stable supply of lithium resources in our country, it is imperative to develop cost?effective and highly efficient technologies for lithium extraction from salt lakes. Recent studies have demonstrated that the combination of emerging membrane separation technology with traditional processes holds great potential for achieving significant advancements in lithium extraction from salt lakes. This review aims to present the latest membrane technologies for extracting lithium from salt lake brine. It comprehensively discusses cutting?edge research findings from various perspectives, including the pore structure of membrane, precise design of the chemical environment within the pores, development of innovative membrane fabrication processes, and the integration of multiple membrane processes. By doing so, the review offers valuable insights and guidance for the design of new membrane materials. Furthermore, the review provides a comprehensive overview of the current bottlenecks faced by membrane separation technology in the process of lithium extraction from salt lakes. It also explores the potential prospects of biomimetic membrane materials.
Polyoxometalates (POMs) are molecular metal oxides composed of transition metals in their highes oxidation states (Mo,W,V,Nb,Ta). The high solubility and low specific surface area of pure inorganic POMs limi its practical applications in polar solvents. Due to the widespread applications of organic?inorganic hybrid POMs and immobilized POMs in the field of catalysis, energy conversion, storage and magnetism have attracted considerable attention.The design and synthesis of transition metal/Lanthanide modified organic?inorganic polyoxometalates and immobilized polyoxometalates composites are reviewed,and the practical applications of POMs with novel structures are summarized and outlooked.
Using Fe(NO3)3·9H2O, H3PO4, Na2MoO4·2H2O, 3?aminomethylpyridine as raw materials, a complex 1 based on the hourglass phosphomolybdate modified with FeⅡ was successfully synthesized by hydrothermal synthesis method. The molecular formula is (C6H10N2)6{Fe[Mo6O12(OH)3(PO4)2(H2PO4)2]2}·3.5H2O. The single crystal X?ray diffraction infrared spectroscopy(FT?IR) powder X?ray diffraction(PXRD) and thermogravimetric analysis(TGA) were used to prove its structure and composition which was analyzed at the same time The results show that complex 1 has a three?dimensional supramolecular framework, which connected {Fe[P4Mo
H(6A)···O(8)， N(2)—H(2C)···O(23)， N(2)—H(2B) ···O(19) and N(1)—H(1A) ···O(30). Besides, the electrochemical detection of furaltadone hydrochloride was further studied by using complex modified carbon paste electrode(1?CPE). The experimental results show that 1?CPE has good stability and high selectivity for furaltadone hydrochloride.
A double polyoxometalates?based composite catalyst material was prepared by Mechanochemistry. In order to compare with the double polyoxometalates?based composite catalyst material, one polyoxometalates?based were prepared by the same method. The structures of these catalysts were characterized by X?ray powder diffraction, Fourier transform infrared spectroscopy, and liquid ultraviolet spectroscopy. The photocatalytic degradation of rhodamine B (RhB) was selected as a model reaction to evaluate its photocatalytic activity and the possible mechanism were further explored in the degradation process. The results indicate that the degradation efficiency of H3PMo12O40&H4SiW12O40@MOF?199 is 92% while irradiating in simulated sunlight for 60 minutes, which is superior to that of the corresponding single POMs catalysts H3PMo12O40 or H4SiW12O40@MOF?199 and has a good cycling activity. The synergistic effect of the good photocatalytic activity of polyoxotungstates and the good oxidation?reduction ability of polyoxomolybdates, which provides a new vision for designing diverse POMs@MOFs composite catalysts with different catalytic properties.
Using N,N'?Dimethylpiperazine as structure directing agent, a 3D open?framework neodymium oxalate [Nd(H2O)(C2O4)2](C6N2H16)0.5?2H2O (compound 1) was synthesized under hydrothermal condition. The single crystal X?ray diffraction reveals that the structure is composed of alternating single?capped tetragonal antiprism NdO9 and oxalic acid units connected to each other. The structure contains three?dimensional 12?membered ring channels, in which water molecules and protonated Me2ppz cations are located in the channels along the b and a axes, respectively. The presence of guest water molecules provides the structural basis for proton conductivity. The results of hydrothermal and acid?base stability tests show that the structure of compound 1 had excellent stability. AC impedance tests show that compound 1 has a high proton conductivity, which is 2.81×10-4 S/cm at 348 K and 98% RH.
The adsorption competitive adsorption and conversion behaviors of thiophene and 1?hexene on Hβ molecular sieve have been studied by using the method of in?situ infrared spectroscopyThe roles of different acidic sites in the alkylation reaction of thiophene and olefin molecule were systematically discussed. The results show that 1?hexene is preferentially adsorbed on the B acid sites, and it s easy to dimerize through protonation activation. Thus,there is a significant competitive relationship between the adsorption of thiophene molecules and the protonation reaction process. Moreover, it can be confirmed that the adsorbed thiophene molecule on non?framework aluminum on zeolite are more likely to its alkylation with a protonation 1?hexene molecule near the center of the B acidThis results can provide basic theoretical guidance for the development of zeolite catalysts for alkylation desulfurization processes.
In order to optimize the effect of Bohai oilfield regulation and flooding in B water injection development, the numerical simulation software of CMG reservoir was used to carry out optimization research on the effect of "weak gel+water?based microspheres" combined displacement to improve recovery,and according to the known geological reservoir properties of the oilfield,the actual three?dimensional geological model was established,and the historical fitting was carried out in combination with the previous production history.The factors affecting the modulation effect of single section of plugged weak gel modulation,single section of water?based microsphere modulation and driving and the factors affecting the modulation effect of "weak gel+water?based microspheres" were analyzed and optimized,and the related production indexes were predicted.The results show that the combined modulation effect of "weak gel+water?based microspheres" is significantly better than that of a single segment of plug modulation and driving.The optimal injection process parameters of the modulated blocking agent (weak gel) were selected through numerical simulation:the injection mass fraction is 0.50% crosslinker,the injection amount is 0.000 11 PV,the injection speed of A2H well is 240 m3/d,and the injection speed of A3H well is 200 m3/d.The optimal injection process parameters of the modulator (water?based microspheres) were selected through numerical simulation: the injection mass fraction is 0.30%,the injection amount is optimally 0.003 00 PV,and the injection speed of A2H and A3H wells is about 500~600 m3/d. This design scheme can effectively achieve the purpose of increasing precipitation and oil recovery.
Aiming at the periodic characteristics of severe slug flow an experimental study was carried out through the downward?riser system. Based on the experimental data and the variation of pressure in the pipe, the variation rule of the severe slug flow period was analyzed and verified reciprocally with the calculation model results. It turned out that the flow state in the tube would change under different experimental parameters such as the inclination angle of the downdip tube, the gas phase conversion velocity or the liquid phase conversion velocity. The time of the slug eruption and slug reflux was basically changeless on account of the height of the riser was invariant, so the period of severe slugging depends on the time of slug formation and slug outflow stages. And it was mainly affected by the inclination angle of downward riser, gas superficial velocity or liquid superficial velocity.
Grinding technology with minimum quantity lubrication technology is a new type of environmentally friendly and efficient processing technology. It has the characteristics of less cutting fluid and low cutting force, and is conducive to the maintenance of the tool and can effectively improve the quality of the workpiece. However, the cooling performance of the high?pressure air flow of the grinding technology with minimum quantity lubrication is very limited, which can not meet the need for cooling in the grinding zone. The traditional casting cooling technology can meet this demand by using a large amount of grinding fluid. In this paper, the research background, development status and latest achievements of micro?lubrication technology were reviewed, which lays a theoretical foundation for further study of the characteristics and principles of these special grinding technology with minimum quantity lubrication..
The study of ultrasonic variable amplitude rods is an important part of ultrasonic vibration system. The cosine half?period cylindrical composite horn was designed to realize the smooth transition between the cosine section and the cylindrical section. By theoretical calculation, its frequency equation and amplification coefficient equation were derived. The results show that the frequency equation of the new cosine cylindrical composite variable amplitude rod is simpler than that of the cylindrical conical composite variable amplitude rod and the stepped variable amplitude rod; the amplification coefficient equation of the new cosine cylindrical composite variable amplitude rod is similar to that of the stepped variable amplitude rod, which is more concise than that of the cylindrical conical composite variable amplitude rod. Using ABAQUS finite element analysis software, modal analysis of the designed cosine cylindrical composite variable amplitude rod was carried out to determine its inherent frequency and vibration type; harmonic response analysis was conducted to check the feasibility of the theoretical design. The results of the modal analysis and harmonic response analysis show that the performance of the ultrasonic composite variable amplitude rod is optimal when the length of the cosine section is 55 and 60 mm. The research results provide a reference for the design and application of ultrasonic composite amplitude rod.
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