Institutional Repository of Institute of Process Engineering, CAS (IPE-IR）
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Highly efficient removal of aromatic diamines from the polyurethane bio-hydrolysate by MIL-53 series MOFs
No full textDue to the biotoxicity and ecological hazards of 2,4-toluene diamine (TDA) and 4,4 '-methylene dianiline (MDA), it is the key process for upcycling polyurethane (PU) waste to remove them from the PU bio-hydrolysate with high selectivity and efficiency. Herein, MIL-53 series metal-organic frameworks (MOFs) were prepared and applied to remove aromatic diamines. Besides, the effects of their different structural units on the adsorption performance were investigated. Among the three metal nodes (Cr3+, Al3+, Fe3+) of MIL-53, MIL-53(Al) demonstrated the highest adsorption capacities upon TDA (4.17 mmol/g) and MDA (2.00 mmol/g) due to its more mu 2-OH sites and higher porosity. Compared with MIL-53(Al), DUT-4 and DUT-5 owned longer linkers but exhibited inferior aromatic diamine adsorption performance, which was ascribed to the more appropriate pore size and more mu 2-OH sites of MIL-53(Al). Notably, MIL-53(Al) exhibited excellent selectivity towards aromatic diamines, while the removal efficiency reached over 90 %. In addition, spectral analysis before and after adsorption revealed the mechanism, which involved host-guest interactions, H-bonding interactions, and pi-pi stacking. The results indicate the great potential of applying the optimal MIL-53(Al) as an alternative adsorbent for removing hazardous aromatic diamines from the PU bio-hydrolysate
Cleaner production of ammonium paratungstate by membrane electrolysis-precipitation of sodium tungstate solution
No full textThe production of ammonium paratungstate (APT) is riddled with the generation of wastewater,which causes environmental problems.To solve the problem of wastewater generation at source,a membrane electrolysis-NH_3·H_2O precipitation method,which prevents wastewater generation and recycles the reagents used in the process,was proposed and investigated in this study.The electrolysis process was investigated based on parameters such as initial cathodic and anodic NaOH concentrations,and current density.The results showed that an increase in current density and initial cathodic NaOH concentration and a decrease in the initial anodic NaOH concentration would enhance the separation of tungsten and sodium.The optimum condition was found at a current density of 666 A·m~(-2),initial anodic and cathodic NaOH concentrations of 69 g·L~(-1) and 40 g·L~(-1),with a current efficiency of 75.40%,and energy consumption for producing 1 ton of NaOH was 2184 kW·h.The precipitation process was investigated based on the acidic high W/Na molar ratio solution obtained by the electrolysis process with NH_3·H_2O as the precipitant.Parameters such as excessive coefficient,temperature,and W/Na molar ratio were studied.The result showed that the variation of excessive coefficient and solution temperature had an opposite effect on the purity of the APT,while an increase in the W/Na molar ratio would increase the product purity.The precipitation product obtained had a purity of 99.6% and was characterized using X-ray diffraction,inductively coupled plasma,and scanning electron microscopy.The methods proposed in this study could provide fundamental information for the design of a cleaner APT production process
Synergistic modification of Ni-rich full concentration gradient materials with enhanced thermal stability
No full textMajor challenge hindering the large-scale applications of Ni-rich cathode materials (CAMs) lies on the poor cycle (especially under elevated temperature or high cutoff voltage) and thermal stability due to the highly reactive Ni4+. Herein, the full concentration strategy is combined with Ti pillar and Li2ZrO3 (LZO) coating modification, on which a high-performance CAM with elevated kinetics and stability, CGTZ-1, is obtained. It proves that both cycle and thermal stability can be greatly enhanced by the concentration gradient design and the LZO coating. Whereas the promoted Li+ diffusion coefficient is largely attributed to the Ti pillar. The optimal resultant CAM shows high capacity retention of 88.1% after 200 cycles under 55 degrees C, while that of pristine is only 32.1%. More importantly, it also shows a high thermal release temperature of 261.5 degrees C (vs 222.3 degrees C of the pristine), which demonstrates the effectiveness of this synergistic modification strategy
Sources apportionment of water-soluble inorganic salts in CPM from coal-fired power plants with different emission control technologies
No full textDifferent control technologies to reduce emissions of sulfur oxides and nitrogen oxides from coal-fired boilers have been adopted globally, leading to significant reductions in these gas emissions, especially over the past several years in China. Comparatively, little attention has been paid to the potential effects of these control technologies on particulate matter (PM) emissions, especially condensable particulate matter (CPM), which is harmful to the atmosphere and human health. In this study, we measured filterable and condensable PM emissions in five coal-fired commercial-scale boilers installed with SNCR or SCR for NOx control and wet, semidry, or dry flue gas desulfurization (FGD) for SO2 emission controls. Water-soluble ionic components in PM were analyzed. The experimental results show that the CPM accounts for 55.9% to 95.1% of total particulate matter (TPM) and is composed primarily of water-soluble SO42-and NH4+, with (NH4)2SO4 being the dominant CPM aerosols. Experimental results also reveal that the flue gas emission control technology significantly affects CPM emission from coal-fired boilers. Since the production of (NH4)2SO4-rich CPM results from the use of ammonia solution for NOx reduction, boilers emit more CPM with SNCR than with SCR because the former operates with a higher ammonia/NOx ratio than the latter. Additionally, the CPM emission is related to the FGD technology installed. Boilers installed with wet FGD emit the lowest CPM, followed by semidry and dry FGDs, because of their decreased capabilities of dissolving and absorbing water-soluble components
Sustainable alternative cathodes of sodium-ion batteries using hybrid P2/ O3 phase Na0.67Fe0.5Mn0.5-xMgxO2
No full textThe Na(0.67)Fe(0.5)Mn(0.5-x)Mg(x)O(2)compound with x = 0.02, 0.04, 0.06, 0.08, 0.1, 0.15 was synthesized by solid state reaction. The structure of the samples gradually transformed from P2 phase to O3 phase with the increase of Mg content. The hybrid P2/O3 phase transition metal oxides with high performance was pre-pared to promote the application of sodium-ion batteries. Na(0.67)Fe(0.5)Mn(0.5-x)Mg(x)O(2)exhibited a hybrid P2/ O3 phase structure, which showed high electrochemical performance. Due to the synergy of P2 and O3 phase, the conductivity for the migration of Na ions in the experimental cell, exhibited the highest ion diffusivity. Here, Fe and Mn-based transition metal oxide materials as a cathode material can have great application potential for sodium-ion batteries and can be one of the most promising alternatives to the limited lithium-ion battery.(c) 2022 Elsevier B.V. All rights reserved
Preparation and characterization of steel slag-based low, medium, and high-temperature composite phase change energy storage materials
No full textIn this study, industrial solid waste steel slag was used as supporting material for the first time, and polyethylene glycol (PEG), sodium nitrate (NaNO3), and sodium sulfate (Na2SO4) were used as low, medium, and high -temperature phase change materials (PCMs). A series of shape-stable composite phase change materials (C-PCMs) were prepared by vacuum impregnation and mixing-sintering methods. The morphology, thermal prop-erties, and thermal reliability of C-PCMs were characterized by scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy (FT-IR), and differential scanning calorimetry (DSC). The results show that the three PCMs are uniformly dispersed in the pores of steel slag, and the maximum loading is 35 %, 40 %, and 50 %, respectively, and they have good chemical compatibility with steel slag. Compared with their pure PCMs, the three prepared C-PCMs showed a reduction in subcooling of 2.64 degrees C, 4.53 degrees C and 0.79 degrees C, respectively, and an increase in thermal conductivity of 172 %, 54.9 % and 82.4 %, respectively, all with good phase change thermal storage properties. Even after 100 thermal cycles, the latent heat retention rate was more than 97 %, which had good thermal reliability. Therefore, it can be concluded that the three kinds of low, medium, and high -temperature C-PCMs have considerable application potential in different temperature areas, such as building latent heat storage, solar energy storage systems, and industrial waste heat recovery system
A Foldable Aqueous Zn-Ion Battery with Gear-Structured Composite as Freestanding Cathode
No full textA foldable battery with high flexibility provides great potential in various wearable electronic devices for health and fitness tracking, chronic disease management, performance monitoring, navigation tracking, and portable gears for soldiers. We report a highly flexible, self-healing Zn-ion battery with a free-standing cathode that is composed of a 3D gear-like NH4V4O10@C composite on carbon paper. The battery retained a capacity of up to 102.4 mAh g(-1) even after being folded 60 times with a high angle of 180 degrees. An aqueous hydrogel consisting polyvinyl alcohol, glycerin and Zn(CF3SO3)(2) was used as electrolyte, which showed as high as 580 % tensile strain under a loading weight of 78 N. The battery exhibited a better capacity retention of over 100 mAh g(-1) and Coulombic efficiency of over 99.8 % after cutting and twisting to 90 degrees, thereby indicating a great self-healing performance. The gear-like geometry greatly improved the volume accommodation due to the increased interval space between the blades and the outward configuration. Meanwhile the Zn2+ ionic conductivity was improved by rapid re-binding of many existing hydroxy groups from the electrolyte and the enhanced contact surface area and diffusion route from the cathode material. The highly flexible, safe aqueous Zn-ion battery opens a practical way to power various carry-on electronics under mechanical agitation
