Institutional Repository of Institute of Process Engineering, CAS (IPE-IR）
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Facile synthesis of nitrogen and sulfur co-doped hollow microsphere polymers from benzothiazole containing wastewater for water treatment
No full textAdvanced oxidation is a very efficient method in wastewater treatment, but it is a waste of resources to directly oxide the high concentration of valuable organics into carbon dioxide and water. In this paper, the combination of persulfate and wet air oxidation was developed to recover organics from high concentration of wastewater, along with high mineralization of the residual organics. Nitrogen and sulfur co-doped hollow spherical polymers with narrow size distribution was recovered from the simulated benzothialzole (BTH) wastewater in this facile way, along with chemical oxygen demand (COD) removal rate higher than 90%. The formation route of the polymers was intensively studied based on detailed analysis of different kinds of reaction intermediates. The polymers can be further carbonized into co-doped hollow carbon microsphere, which showed better performance in organic contaminants removal than a commercial activated carbon both in adsorption or catalytic persulfate oxidation. This proposed a new strategy to simultaneously combine oxidation and polymerization for resource recovery from wastewater with high concentration of heterocyclic compounds
Harnessing Ostwald ripening to fabricate hierarchically structured mullite-based cellular architecture via the gelation network-triggered morphology-regulation method
No full textGas-in-liquid foam templating is considered as a promising method for commercial-scale production of porous materials. However, Ostwald ripening occurs frequently during the preparation, which could bring about inhomogeneous bubbles with large sizes and deteriorate the performance of resultant products. To tackle this challenging task, we report a gelation network-triggered morphology-regulation strategy during the foaming process. As an exemplar, boehmite sol was incorporated into the andalusite suspension to stabilize the foam framework. After casting, the wet foam was able to maintain its overall shape, since andalusite particles were anchored onto the gas-liquid interface by the gelation network during mechanical frothing. The samples calcined at 1400 degrees C feature homogeneous bubble with hierarchical porous architecture, smaller pore size with a mean value of 5.32 mu m and robust compressive strength of 11.97MPa at a porosity level of 84 %. Our approach substantially broadens the design philosophy of high performance porous ceramics
Infiltration and resuspension of dilute particle suspensions in micro cavity flow
No full textSedimentation of particle suspensions in a channel flow into a cavity is analysed numerically using a lattice Boltzmann method coupled with a discrete element method. The work focuses on the entrapment of particles inside a confined cavity and the particle dynamics after entrapment. A close examination of the particle motions reveals three distinct dynamic behaviours: i) resuspension, ii) circulation in the central vortex and iii) deposition to the rear edge of the cavity. The effects of fluid inertia, particle density and cavity size on the infiltration and resuspension behaviours are systematically investigated. The results show that decreasing the Reynolds number, and increasing the length and depth of the cavity all lead to an increase in the trap efficiency. Three distinctive regimes with respect to the trap efficiency were then identified by deriving an empirical dimensionless trap number T-p: a resuspension regime when T-p 2.5. (c) 2021 The Author(s). Published by Elsevier B.V
A review of multiple Pickering emulsions: Solid stabilization, preparation, particle effect, and application
No full textThe emulsions stabilized by solid particles, Pickering emulsion, have excellent stability and are environ-mentally friendly compared to the emulsions stabilized by surfactants upon most occasions. The physi-cal-chemical properties of emulsion system, such as stimuli responsive, controllable release and mechanical strength can be precisely tuned through the particle properties and preparation process. This review has carried on the target-oriented summary about the recent progress and applications of multiple Pickering emulsions. The unique superiority of Pickering stabilization at liquid-liquid interface is discussed. The particle wettability has been proved to play an important role in emulsions formation and stabilization. How to prepare multiple Pickering emulsions successfully are described based on emul-sification process and novel technologies. And the influence of particles on the multiple emulsion prop-erties are analyzed. In addition, we present the applications of multiple emulsions in material preparation, such as microspheres and microcapsules, and its application for reaction process is prospected. (C) 2021 Elsevier Ltd. All rights reserved
Catalytic Transformation of PET and CO2 into High-Value Chemicals
No full textPolyethylene terephthalate (PET) and CO2, two chemical wastes that urgently need to be transformed in the environment, are converted simultaneously in a one-pot catalytic process through the synergistic coupling of three reactions: CO2 hydrogenation, PET methanolysis and dimethyl terephthalate (DMT) hydrogenation. More interestingly, the chemical equilibria of both reactions were shifted forward due to a revealed dual-promotion effect, leading to significantly enhanced PET depolymerization. The overall methanol yield from CO2 hydrogenation exceeded the original thermodynamic equilibrium limit since the methanol was in situ consumed in the PET methanolysis. The degradation of PET by a stoichiometric ratio of methanol was significantly enhanced because the primary product, DMT was hydrogenated to dimethyl cyclohexanedicarboxylate (DMCD) or p-xylene (PX). This synergistic catalytic process provides an effective way to simultaneously recycle two wastes, polyesters and CO2, for producing high-value chemicals
Green and Highly Efficient Wool Keratin Extraction by Microwave Induction Method
No full textKeratin is a plentiful and renewable fibrous protein resource found in nature, but a great deal of keratin-containing waste causes environmental problems, especially wool waste, which accounts for the majority. A green and efficient extraction method of keratin based on microwave induction method was studied. Compared with traditional thermal induction, the extraction time was shortened by half, and the dissolution rate of the wool was improved. The effects of the above two methods on the size, structure, crystallinity, and thermal stability of wool keratin were studied by a series of analysis methods [e.g., attenuated total reflectance Fourier transform infrared spectrometry (ATR-FTIR), Raman spectroscopy, X-ray diffraction spectroscopy (XRD), dynamic light scattering (DLS), thermogravimetric analysis (TG), and so on]. The results showed that under microwave irradiation, the disulfide bonds were destroyed greatly, and the secondary structure changed significantly, which was beneficial to obtain wool keratin with low crystallinity and small particle size
Ru(dppbsa)-catalyzed hydrodeoxygenation and reductive etherification of ketones and aldehydes
No full textMethods for the Ru(dppbsa)-catalyzed hydrodeoxygenation and reductive etherification of ketones and aldehydes were developed. Carbonyl substrates without beta-CH functionality follow a hydrogenation-hydrogenolysis path, wherein the hydrogenolysis of the alkanol intermediates is the rate-limiting step. By contrast, a hydrogenation-dehydration-hydrogenation path is followed by carbonyl substrates with beta-CH functionality, suffering from rate-limiting sulfonate ligand-assisted reversible H-2 cleavage. This hydrodeoxygenation is competitive with reductive etherification when using alkanols as hydrogen surrogates. The chemoselectivity can be adjusted based not only on the bond strengths of O-H and C-H bonds in the alkanols but also on the steric hindrance of the carbonyl substrates. As a result, both hydrodeoxygenation and reductive etherification exhibit excellent aldehyde tolerance, while the reductive etherification of ketones is highly hindered based on this protocol
Lignocellulosic nanofibril aerogel via gas phase coagulation and diisocyanate modification for solvent absorption
No full textCellulose-based aerogels are considered to be carriers that can absorb oils and organic solvents owing to the merits of low density and high surface area. However, the natural hydrophility and poor mechanical strength often obstruct their widespread applications. In this work, Miscanthus-based dual cross-linked lignocellulosic nanofibril (LCNF) aerogels were prepared by gas phase coagulation and methylene diphenyl dissocyanate (MDI) modification. Due to physical and chemical cross-linking strategies, the optimally 4 M-LCNF aerogels had high surface area of 157.9 m2/g, water contact angle of 138.1 degrees, and enhanced compression properties. Moreover, the modified aerogels exhibited absorption performance for various organic solvents, and the maximal absorption capacity of chloroform was 42 g/g aerogel. Because LCNF was directly produced from Miscanthus without using bleaching reagents, this research provided a more sustainable methodology to utilize lignocelluloses to design robust aerogels to deal with the leakage of oil and organic solvents in industrial applications
Emission Characteristics of NOx and SO2 during the Combustion of Antibiotic Mycelial Residue
No full textThe antibiotic mycelial residue (AMR) generated from cephalosporin C production is a hazardous organic waste, which is usually disposed of by landfilling that causes potential secondary environmental pollution. AMR combustion can be an effective method to treat AMR. In order to develop clean combustion technologies for safe disposal and energy recovery from various AMRs, the emission characteristics of NOx and SO2 from AMR combustion were studied experimentally in this work. It was found that the fuel-N is constituted by 85% protein nitrogen and 15% inorganic nitrogen, and the fuel-S by 78% inorganic sulfur and 22% organic sulfur. Nitrogen oxide emissions mainly occur at the volatile combustion stage when the temperature rises to 400 degrees C, while the primary sulfur oxide emission appears at the char combustion stage above 400 degrees C. Increasing the combustion temperature and airflow cause higher NOx emissions. High moisture content in AMR can significantly reduce the NOx emission by lowering the combustion temperature and generating more reducing gases such as CO. For the SO2 emission, the combustion temperature (700 to 900 degrees C), airflow and AMR water content do not seem to exhibit obvious effects. The presence of CaO significantly inhibits SO2 emission, especially for the SO2 produced during the AMR char combustion because of the good control effect on the direct emission of inorganic SO2. Employing air/fuel staging technologies in combination with in-situ desulfurization by calcium oxide/salts added in the combustor with operation temperatures lower than 900 degrees C should be a potential technology for the clean disposal of AMRs