查看更多>>摘要：Owing to the complex physical and chemical reactions, optimization of the coal gasification process requires a large computational cost. In chemical engineering design and optimization, the surrogate model is often used to assist the evolutionary algorithm (EA) in solving computationally expensive problems. In this paper, a dynamic model management strategy based on adaptive surrogate selection (ASS) is proposed to identify an appropriate surrogate model to assist the particle swarm optimization (PSO) algorithm faced with complex problems. In ASS, based on the given dataset, a right surrogate model was selected from the diversity model library by adopting the minimum root mean square error and K-fold cross-validation before assisting PSO to identify an optimal solution, and reselected constantly with the addition of a new sample. Based on the ASS, in addition to the adaptive global model, the local model is introduced and selected adaptively to refine the optimal solution more rapidly, then switched dynamically with the global model. The most uncertain sample was also considered for searching the unexplored region and escaping from the local optimum. Comparison of the specific surrogate EAs and three other state-of-the-art surrogate-assisted EAs revealed that the proposed strategy significantly improved the optimization performance of PSO and the effective syngas yield of the coal gasification process. (C) 2021 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
查看更多>>摘要：Background: Multilayer hollow materials have attracted considerable attention as potentially valuable in drug delivery, catalysis, and nanoreactors. The main purpose of this work is to synthesize hybridized triple-shelled hollow mesoporous organosilica nanoparticles (htHMONs) with ethane-, benzene-, and thioether groups. Methods: The nanoparticles are prepared using a surfactant-directed co-assembly process and a following hydrothermal etching strategy. First, hybridized mesostructured organosilica nanoparticles were synthesized via step-by-step adding multiple organosilica in a surfactant solution. The mesostructured organosilica nanoparticles are then transformed into htHMONs by hydrothermal treatment at 160 degrees C for 3 h. Finding: The prepared typical htHMONs possess a uniform diameter (320 nm), independent core (107 nm), and three separate shells (10, 13, and 23 nm from outside to inside). In addition, htHMONs possess typical properties of mesoporous materials, including uniform mesopore (4.20 nm), large specific surface area (SSA) (458 m(2)g(-1)), and huge pore volume (0.82 cm(3)g(-1)). Furthermore, htHMONs with various sizes (190-330 nm) are also prepared by varying the amount of structure-directing agent or volume ratio of water to ethanol. (C) 2021 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
查看更多>>摘要：Background: The pressing demand to increase agricultural productivity amid the rapidly growing population has exponentially boosted fertilizers usage. Phosphate (Pi) runoff from fertilizers induces eutrophication in water sources and severely affects its surrounding ecosystems. To cope with Pi accumulation problem, this study reported the synthesis of an environmentally friendly magnetic adsorbent, namely Fe3O4/thiamine (thF). Method: A one-step chemical oxidation and functionalization technique for thF synthesis was developed. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FTIR), nitrogen (N-2) sorption, and superconducting quantum interference device (SQUID) analysis were conducted to ensure the formation of Fe3O4, confirm the successful incorporation of thiamine, and gain insight into the factors influencing the adsorptivity of thF-363. Significant Findings: The thF synthesized at 363 K (thF-363) produces an adsorbent with the highest Pi removal efficiency compared to other synthesis conditions. The thF-363 showed up to 1.51-fold higher adsorption capacity than the unmodified Fe3O4. The large surface area and occurrence of thiamine functional groups are the contributing factors in enhancing its adsorption capacity for Pi removal. The thF-363 did not adversely affect the growth of the model plant, Arabidopsis thaliana; demonstrating its suitability as an environmentally friendly adsorbents for Pi removal from eutrophicated water with the feasibility of magnetic separation from an aqueous system. (C) 2021 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
查看更多>>摘要：Background: A rotationally reciprocating impeller separates the horizontal cross-section of the vessel into two mixing regions under a laminar flow regime. In this study, we investigated the separation mechanism from the dynamics of the streakline on the boundary Methods: The stretching behavior of the streakline on the universal boundary of active mixing regions was successfully visualized by injecting tracer fluid from a specific position Findings: The elongational rate of streakline proportionally increased with the increase in Reynolds number. Besides, the linear component of the elongation rate drastically changed at Re similar to 10 due to the bending of the boundary. Compared with other chaotic mixing flows, we proved that tracer particles are enclosed in turnstile lobes at the hyperbolic fixed point at the wall, transported on the boundary, namely separatrix, to the mixing shaft being another hyperbolic fixed point, and then distributed evenly into both mixing regions. It was concluded that the boundary becomes wavy at Re > 10, which increases the area of turnstile lobes to enhance fluid transportation between two mixing regions (C) 2022 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
查看更多>>摘要：Background: Nonionic surfactant has the combined merits of easy production, low toxicity and high surface activity, which can be deemed as the potential inhibitor with good prospect. The nonionic surfactant of coconut diethanolamide (CDEA) has no cloud point comparing with other nonionic surfactants, and the acylamide group of O=C-N in its hydrophilic head can make the good hydrolysis resistance of CDEA. Methods: The inhibition effect of CDEA was studied as a novel corrosion inhibitor for cold rolled steel (CRS) in both HCl and H2SO4 solutions for the first time by weight loss, potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) methods. The micro-morphologies and chemical compositions of CRS surfaces were fully characterized by scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), atomic force microscope (AFM), confocal laser scanning microscope (CLSM), X-ray photoelectron spectroscopy (XPS) and contact angle measurements. The critical micelle concentration (CMC) values of CDEA in HCl and H2SO4 media were determined by surface tension measurements. Moreover, quantum chemical calculations and molecular dynamic (MD) simulations were used to theoretically study the adsorption sites and modes of CDEA. Significant findings: CDEA acts as an efficient inhibitor, and the maximum inhibition efficiency of 50 mg L (1) CDEA is above 95% in 1.0 M HCl, and 92% 0.5 M H2SO4 from weight loss method. The adsorption of CDEA on CRS surface completely obeys Langmuir isotherm, and the standard adsorption Gibbs free energy is around -40 kJ mol (1). CDEA can be arranged as a mixed-type inhibitor in both acids, while exhibits more anodic inhibition in HCl solution. The presence of CDEA significantly increases the charge transfer resistance, while decreases the double layer capacitance. Inhibition efficiency follows the order: 1.0 M HCl > 0.5 M H2SO4. A series of micro-morphologies of CRS surfaces by SEM, AFM and CLSM confirm efficient inhibition of CDEA for steel in strong acids. EDX and XPS provides the distinct proof of adsorption of inhibitor molecules. The inhibited CRS surface is turned to be hydrophobic with an obtuse contact angle. The adsorption reaches saturated state at CMC of 0.10 mM. The hydrophilic groups of -OH and -CON- are the active adsorption sites of CDEA, while the hydrophobic chain of -C11H23 extends to the aqueous solution phase. (C) 2021 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
查看更多>>摘要：Background: The close boiling points of carbon tetrafluoride (CF4) and nitrogen trifluoride (NF3) and the chemical inertness of CF4 make it difficult to remove it from NF3. Methods: A method for cleaning NF3 from CF4 at the gas-liquid interface is proposed. The purification is carried out by a sequence of cycles: (1) fractional condensation of NF3 at a cryostat temperature (T-cry), at which the equilibrium pressure of CF4 exceeds its partial pressure in the feed mixture; and (2) pumping out the gas phase enriched with CF4 and high-boiling impurities. The cycles are repeated at a next T-cry corresponding to the new CF4 content, and are completed by cryogenic distillation of the condensate with the removal of low-boiling impurities. Findings: The CF4 content of 5000 ppm in a 25 g NF3 sample was reduced to less than 100 ppm in three cycles at T-cry = 120 K; a CF4 separation coefficient above 40 was achieved. The method can be used for the industrial production of high-purity NF3, with the cryostat refrigerant being the only consumable material, as well as for the separation of other substances with close boiling points, such as isomers or isotopes. (C) 2021 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
查看更多>>摘要：Background: Methanol electro-oxidation reactions (MOR) are utilized to provide electricity in direct methanol fuel cells (DMFC), which requires a reasonable design of catalysts to accelerate sluggish MOR. Herein, a series of cobalt oxides have been doped with a foreign oxophilic transition metal (Bi) by the sol-gel method and further calcination treatment. Methods: The composition and structure of Bi0.13Co2.87O4-550 were characterized by the scanning electron microscopy (SEM), the powder X-ray diffraction (XRD), and X-ray photoelectron spectra (XPS). Evaluate the electrocatalytic performance of materials by cyclic voltammetry, chronoamperometry, and impedance spectroscopy. Significant findings: By virtue of the tunable compositional and structural advantages, the optimized Bi0.13Co2.87O4-550 nanocomposite shows the excellent electrocatalytic activity, very high mass activity (808.5 mA mg(-1)), as well as remarkable durability to resist CO poisoning during methanol oxidation. The excellent electrocatalytic activity for MOR is attributed to the high specific surface area, abundant active sites and superior mass transportability. Furthermore, the oxidation of other alcohols including ethanol, ethylene glycol and glycerol are also realized by the electrocatalysis of Bi0.13Co2.87O4-550. This work provides a good idea for the design of non-precious metal electrocatalysts with the high performance. (C) 2021 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
查看更多>>摘要：Background: Diclofenac sodium is a kind of classic pharmaceutical and personal care product which has a potential risk to aqueous environment and food chain. The aim of the study is to realize the removal of diclofenac sodium in an energy-efficient and eco-friendly way. Method: TiO2 nanoparticles were modified with aminopropyltriethoxysilane and then were grafted with polydopamine and chitosan sequentially through Schiff-base reaction to realize spatiotemporal coagulation and degradation of diclofenac sodium under visible light irradiation, which was rare reported before. Results: The polymer layer of modified TiO2 nanoparticles became swelling and outstretching with cooling the temperature from 313.15 +/- 0.2 to 293.15 +/- 0.2 K, which led to the exposure of the TiO2 nanoparticle surface and the photocatalysis of which was activated. Photoelectrons migrated to the surface of which due to the protonation of TiO2 nanoparticles in acidic aqueous milieu and reacted with OH- forming center dot OH at the presence of oxygen and the photocatalytic efficiency of which was improved. It further reacted with diclofenac sodium and the coagulant could be directly reused at least twenty times without rinse process in this work, which has a significantly application potential considering future benefits. (C) 2021 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
查看更多>>摘要：Background: Eco-friendly thermally insulating cellulose aerogels made from environmentally friendly resources are very attractive in materials chemistry, but the high flammability limits their application. Method: Herein, a novel phosphorus-containing flame retardant modifying agent (DOPO-IA) was incorporated into the cellulose nanofiber aerogel and the cellulose composite aerogels were prepared by esterification and followed by a freeze-drying process. Findings: The thermal conductivity of the resultant cellulose composite aerogels was in the range of 28.6-31.2 mW/(mK). Meanwhile, the cellulose aerogels modified with DOPO-IA showed significantly enhanced thermal stability, mechanical property, and flame retardant performance compared with the pure cellulose aerogel. The CNF-DI-3 showed a high char residue (19.8 wt%) at 700 degrees C, which was 187% higher than CNF. Specifically, CNF-DI-3 exhibited remarkable reductions in its PHRR and THR values which were 67% and 60%, respectively, as compared to those of CNF. In summary, it is of significance to synthesize mechanically robust and flame-retardant cellulose aerogels. (C) 2021 Published by Elsevier B.V. on behalf of Taiwan Institute of Chemical Engineers.
Liu, Wei-JieKwon, EilhannThanh, Bui XuanKhiem, Ta Cong...
8页
查看更多>>摘要：As ensulizole (ESL) is a widely-used UV absorber, release of soluble ESL into the aquatic environment would pose risks to the ecology because ESL is an endocrine disrupting compound. For establishing efficient processes to eliminate ESL from water, sulfate radical (SR)-based advanced oxidation processes are preferable owing to stronger oxidation potential of SR. Recently, cobalt sulfides (CoS) have drawn growing attention as CoS is validated to possess more active redox characteristics, making CoS a more powerful catalyst for activation monopersulfate (MPS) to generate SR. Since structures of catalysts determine their catalytic activities, a unique hexagonal hierarchitectured CoS (HHCS) is developed here through a simple one-step hydrothermal reaction to consist of a 3D hexagonal particle embedded with nanosheets interwoven for serving as a heterogeneous catalyst to activate MPS for degrading ESL. With HHCS = 100 mg/L and MPS = 300 mg/L, 5 mg/L of ESL is completely eliminated in 60 min, and HHCS surpassingly outperforms Co3O4 for degrading ESL. E-a of ESL degradation by HHCS+MPS is also determined as a relatively low value of 48.2 kJ/mol. The activation mechanism/degradation pathway of ESL degradation by HHCS + MPS is investigated to understand degradation behaviors for developing SR-based processes of ESL degradation using CoS catalysts. (C) 2021 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
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Elsevier