Chemical Engineering & Technology最新文献

A highly stable and electrochemically active porous molybdenum carbide (PMC) has been synthesized from agricultural waste by carburization of bagasse under inert conditions. The surface area and porous structure of the resulting PMCs can be tuned by varying the synthesis conditions. The PMCs obtained have been characterized via XRD, XPS, SEM, and gas physisorption techniques. The final PMC materials are highly crystalline with nanoscale porosity and with an active surface area of up to 717 m².g⁻¹. This work unlocks a promising avenue for developing highly active electrochemical nanomaterials using green synthesis, potentially eliminating the need for noble metals. The results demonstrate a six-fold increase in the electrochemical signal.

The selection of adsorbents is critical for developing an adsorption unit. In this study, a activated carbon fibers (ACF) and a granular-activated carbon (GAC) were evaluated in dynamic toluene adsorption to determine their benefits and limitations. A variety of physicochemical approaches were used to characterize the samples. Adsorption under varied circumstances demonstrated that ACF has a larger adsorption capacity and a longer saturation time than GAC. The Langmuir isotherm suited equilibrium data well. Thermodynamic characteristics showed that adsorption was spontaneous and exothermic. The adsorption kinetics were found to be dominated by the pseudo-first-order model, with GAC having a greater sorption rate. Thermal regeneration appeared to be more favorable for ACF.

Converting the abundant biomass resources in nature into fine chemicals can not only reduce carbon emissions but also effectively deal with the depletion of fossil energy, which is of strategic significance for sustainable development. In this paper, by optimizing the content of bimetallic components, highly active co-doped Co₁Cu₃ bimetallic silicate was designed and synthesized. After reduction, a highly dispersed and stable Co₁Cu₃/SiO₂ catalyst was obtained, which was used to catalyze the aqueous phase hydrogenation of furfural (FFR) to cyclopentanone (CPO). Compared with the traditional supported catalyst, the Co₁Cu₃/SiO₂-ammonia evaporation (AE)-300 catalyst prepared by AE has the best performance. Under the optimal reaction conditions, the conversion of FFR was as high as 95.1 % and the selectivity of CPO was 88.6 %. This high activity can be attributed to the formation of highly dispersed and uniform metal active sites with low content of Co. At the same time, the formation of flocculent silicate enhances the synergism between CoCu and SiO₂ support and increases the specific surface area of the catalyst. In addition, the experimental results show that the reaction carbon balance will be destroyed with the high concentration of FFR solution.

Nowadays, due to the lack of drinking water and the increase in global demand, desalination by reverse osmosis (RO) has been developed. In this regard, activities have been carried out to increase water flux and salt removal, which are important indicators in this process, including membrane modification by loading nanoparticles (NPs). Process simulation plays an important role in reducing laboratory costs, improving efficiency, and investigating operational parameters in more detail. This is an important factor that leads us to process simulation. The simulation of the RO process by thin-film composite membranes modified with nanoporous titanate (mNTs) NPs has been conducted using COMSOL software. The performance of this process was checked by loading different amounts of mNTs with the desired membrane. The results revealed that by adding 0.01 w % of mNTs to the membrane composition, the performance of the process was improved in that the initial water flux through the membrane increased by about 95.4 %, while the salt rejection remained nearby 98 % and did not decrease much. Finally, to validate and expand the simulation results, the model outcomes were compared with experimental data, and the mean relative error for water flux and salt removal percentage was 1.15 % and 0.83 %, respectively.

The impact of radial dispersion of both heat and mass on the behavior of cooled fixed-bed reactors was explored using a two-dimensional reactor model. This study accounted for dispersion through an effective radial thermal conductivity (λ_rad) and a radial dispersion coefficient of mass (D_rad), with Fischer–Tropsch synthesis serving as an illustrative process example. Under moderate reaction conditions and hence still rather gentle radial temperature profiles, the effect of mass dispersion on reactor performance was found to be minimal, even if disregarded (D_rad = 0), whereas dispersion of heat (λ_rad) always significantly impacts reactor behavior. Nevertheless, for precise thermal runaway predictions by a reactor model, incorporating mass dispersion by a realistic D_rad value is essential.

Acetylene hydrogenation reactions (AHR) are typically carried out in fixed bed reactors (FBRs) with high diameter-to-particle diameter (D/d). In this study, first, a real catalyst bed was built using the discrete element method, and the suitability of the bed was assessed using empirical equations. Second, a discrete element method-computational fluid dynamics (DEM-CFD) model was developed using CFD in conjunction with the reaction mechanism to simulate the AHR in the FBR and was compared with the experimental results. The results show that the DEM-CFD can well predict the 3D interactions of velocity, temperature, and species for different D/d. The results can provide favorable theoretical guidance for the optimization of FBR and process intensification.

This study focuses on designing a solar thermal system utilizing parabolic trough collectors to replace conventional heat requirements in industrial processes. The research also assesses the impact of implementing this system on reducing CO₂ emissions and provides economic analysis for industrial cities from two geographically different islands in Indonesia: Java and Sulawesi. This study uses a parabolic trough collector to absorb energy from sunlight. Based on the calculation of the energy balance of the solar collector, the average heat absorbed by the collector is 545.5 kJ m⁻² h⁻¹ in Java and 606.5 kJ m⁻² h⁻¹ in Sulawesi. As a result, approximately 67.55 tonnes of CO₂ per day will be mitigated by transitioning from conventional processes. The economic analysis indicates a payback period of 3.54 years, a net present value of 1.4 million USD, and an internal rate of return of 12 % based on fuel savings.

The degradation of ciprofloxacin hydrochloride (CFX), an extensively utilized antibiotic for bacterial infections, has been studied through the application of advanced oxidation processes (AOPs) including hydrodynamic cavitation (HC), ozonation (O₃), the Fenton reaction, chemical oxidation, and hybrid AOPs such as HC/O₃ and Fenton/O₃. Among these, the hybrid combination of HC/O₃ demonstrated the highest CFX degradation of 99.82 % within 180 min having an initial concentration of 1000 ppm. The optimization of the HC/O₃ process was conducted by varying parameters including initial concentration, pH, ozone (O₃) gas flowrate, and temperature. Throughout the degradation process, CFX underwent intermediate formation, which gradually degraded over time.

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