Category Archives: Chemical Engineering & Technology

COVID‐19: Medical Waste Management, Impact on Sustainable Development Goals, and Bibliometric Analysis

Posted on 1 September 2023 by

Sustainable and innovative solutions for managing medical waste and mitigating its impact on public health and environment are reviewed. Focusing on the sustainable development goals (SDGs), various methods of medical waste management are evaluated. The findings underscore the need for international collaboration and further research to achieve the SDGs and address medical waste management challenges.

Abstract

This comprehensive review examines various methods of treating medical waste in the context of the sustainable development goals (SDGs). A bibliometric analysis was conducted to investigate the impact of COVID-19 on medical waste, which showed a notable increase in publications in recent years. Findings indicate that thermal treatment with energy recovery, including pyrolysis, gasification, oxidation, and plasma gasification, is the most effective approach for managing medical waste. However, research on the impacts of medical waste on SDGs is insufficient, warranting further investigations to better understand the intersections between medical waste management and the SDGs. The need for international cooperation and collaboration in addressing medical waste management challenges, especially during crises, is highlighted. Understanding the links between medical waste management and the SDGs is crucial in developing sustainable solutions aligned with the global sustainability agenda. Further research and international collaboration are needed to address the challenges associated with medical waste management and contribute to the achievement of the SDGs.

Resource Utilization of Waste Medicine: A Case of Furazolidone Used for Oilfield Water Treatment

Posted on 31 August 2023 by nZhongying Xu, nYefei Wang, nXuewen Cao, nShidong Zhu, nYing Tangn

To solve the problem of waste medicine more reasonably, furazolidone (FDZ) was employed in a case study to investigate its potential for application in oilfield water treatment as acidizing corrosion inhibitor and bactericide. FZD exhibits high inhibitory efficiency under acidic conditions. This work provides a simple and beneficial way to resource utilization of waste medicine.

Abstract

As a case study in the practical problem of how to solve the issue of waste medicine more reasonably, furazolidone (FZD) was investigated as an acidizing corrosion inhibitor and bactericide for oilfield water treatment. Gravimetric results indicate that FZD exhibits high inhibitory efficiency under acidic conditions. In addition, the corrosion inhibition performance decreases as the temperature increases. The adsorption of FZD on the surface of steel has been studied, and the experimental results indicate that the material exhibits the characteristics of a Langmuir-type adsorption isotherm. The thermodynamic results demonstrate that the adsorption behavior of FZD on the steel surface is that of an exothermic, spontaneous, entropy-decreasing process. Finally, the bactericidal activity of FZD was investigated. This work provides a simple and beneficial way to utilize a particular waste drug.

Synthesis of Catalysts Containing Mixed Oxides of Mo‐V‐Cu‐W to Produce Acrylic Acid: A Comparison between Hydrothermal Synthesis and Coprecipitation

Posted on 31 August 2023 by nWellina Missassi Fantim, nJoão Guilherme Rocha Poço, nSilas Derenzon

In order to convert glycerol into acrylic acid, catalysts were synthesized containing mixed oxides of molybdenum, vanadium, and other metals like tungsten and copper via hydrothermal treatment and coprecipitation to evaluate how these preparation techniques influence the physicochemical and morphological properties of the materials and their selectivity for obtaining acrylic acid.

Abstract

Mixed oxides of Mo-V-W-Cu were prepared by three different synthesis methods, namely, evaporation (EV), hydrothermal treatment (TH), and evaporation, followed by hydrothermal treatment (EV-TH). The catalyst samples were characterized by X-ray diffraction (XRD) and fluorescence (XRF), Fourier transform infrared spectroscopy (FTIR), and N₂ adsorption/desorption techniques. Subsequently, their catalytic performance was evaluated for the oxidation of acrolein to obtain acrylic acid. The results revealed that the composition of the crystalline phases of the mixed oxide catalysts influences their catalytic performance, and this effect varies depending on the synthesis method. The catalysts synthesized by EV-TH showed better catalytic results than catalysts synthesized solely via EV or TH methods. This improvement may be attributed to the higher content of vanadium oxides found in the samples of EV-TH, along with the formation of V_0.35Mo_4.65O₁₄ as the predominant crystalline phase.

Synthesis of Phase‐Selective Ionic Liquid Gels and Application to the Synthesis of Ethyl Acetate

Posted on 29 August 2023 by nHuiru Liu, nRuixue Xie, nZhice Xun

An ionic liquid gel (ILG) with temperature sensitivity and phase selectivity was constructed as an ecofriendly and green catalyst for esterification. The ILG was a sol at high temperature, in which the catalytic reaction ran in a homogeneous system. With decreasing temperature, it became a gel, enabling the efficient separation of catalyst and product.

Abstract

Novel and environment-friendly ionic liquid gels (ILG) were synthesized based on polymers, phenylboronic acid, and [BMIM]HSO₄, in order to solve the problems in esterification, such as poor selectivity, difficult separation of product and catalyst, and catalyst recycling. The stability and structures of the ILG were characterized by rheology, thermogravimetric analysis, Fourier transform infrared and ¹H nuclear magnetic resonance spectroscopy, and energy calculation. The solubility data proved that the ILG had phase selectivity, which could enable a homogeneous reaction. The synthesis of ethyl acetate was chosen to evaluate the catalytic activity, with the product yields being higher than 80 %. The catalyst could be recycled directly, without any post-treatment. Thus, the ILG could enhance the industrial application of esterification.

Thermomechanical Modeling of the Stabilization Process for Carbon Fiber Production

Posted on 29 August 2023 by

A hybrid semi-parametric model for the continuous oxidative thermal stabilization of polyacrylonitrile precursor fibers is described. Process temperature, residence time, fiber stretching, and the fiber density of the precursor are considered as influencing parameters. The model may be a first step for cheaper tailored fibers and offers a novel plant-transferable optimization solution.

Abstract

Within carbon fiber manufacturing, the stabilization process is the most time- and energy-intensive process due to the complexity of chemical structure transformation. Therefore, optimization is strictly required to enable cost-efficient stabilization processes. For the first time, a hybrid semi-parametric model for continuous stabilization is developed to prognose stabilization progress and density of the stabilized fiber. The proposed model takes the process parameters like dwell time, stabilization temperature, and fiber stretching as well as precursor properties, such as fiber density, into account. Finally, the proposed hybrid semi-parametric model offers a novel plant-transferable optimization solution for model-based energy optimization in the stabilization process.

ZIF‐8 Incorporated in an Optimized Pebax®1657/PES Membrane for Pure and Mixed CO2/CH4 Gas Separation

Posted on 29 August 2023 by nSamira Mosleh, nMohammad Reza Mozdianfard, nGhader Khanbabaein

A novel optimized mixed-matrix membrane (MMM) of Pebax/polyethersulfone filled with ZIF-8 nanoparticles was fabricated and investigated for pure CO₂, CH₄, and N₂ gases and CO₂/CH₄ binary gas mixtures. The MMM offered higher permeability and selectivity in comparison with the neat membrane and exceeded Robeson's upper bound.

Abstract

Synthesized ZIF-8 (zeolitic imidazolate framework-8) nanoparticles were embedded in Pebax®1657/polyethersulfone (PES) to construct a mixed-matrix membrane. The membrane was characterized by scanning electron microscopy, thermogravimetric analysis, differential scanning calorimetry, and tensile tests. The separation performance of CO₂ from CH₄ and N₂ was also measured at feed pressures of 4, 8, and 12 bar at room temperature. The results indicated that adding nanoparticles and glassy polymer into the Pebax®1657 matrix led to improved thermal and mechanical stabilities of the membrane and an 88 % increase in CO₂ permeance (at 30 wt % ZIF-8 in Pebax®1657/PES-10 %). The Pebax®1657/PES/ZIF-8 membrane exceeded Robeson's trade-off upper bound.

Efficiency Analysis of the Discrete Element Method Model in Gas‐Fluidized Beds

Posted on 25 August 2023 by nBabak Aghel, nFalah Alobaid, nChristoph Graf, nBernd Epplen

The efficiency and accuracy of the Euler-Lagrange/discrete element method model by changing the stiffness coefficient and fluid time step for different particle numbers and diameters were investigated. According to the results, the higher stiffness coefficients improve the simulation accuracy slightly, however, the average computing time increased exponentially.

Abstract

The efficiency and accuracy of the Euler-Lagrange/discrete element method model were investigated. Accordingly, the stiffness coefficient and fluid time step were changed for different particle numbers and diameters. To derive the optimum parameters for simulations, the obtained results were compared with the measurements. According to the results, the application of higher stiffness coefficients improves the simulation accuracy slightly, however, the average computing time increases exponentially. For time intervals larger than 5 ms, the results indicated that the average computation time is independent of the applied fluid time step, while the simulation accuracy decreases extremely by increasing the size of the fluid time step. Nevertheless, using time steps smaller than 5 ms leads to negligible improvements in the simulation accuracy, though to an exponential rise in the average computing time.

Electrochemical Catalytic Synthesis of CH3OH for In‐situ Resource Utilization

Posted on 25 August 2023 by nQingjun Yang, nRizhi Dong, nRui Zhu, nXuan Wang, nShangru Yangn

The supply of resources is an important factor in realizing a sustainable development of outer space exploration. In-situ resource utilization (ISRU) can convert CO₂ into O₂, allowing resource recycling and reducing material supply requirements. An electrochemical catalytic synthesis of a CH₃OH device for ISRU was designed to perform the generation of O₂ and the reduction of CO₂ at room temperature.

Abstract

In space exploration activities, a large amount of materials needs to be carried, which limits the sustainable development of exploration activities. In-situ resource utilization (ISRU) is an important means to realize resource recycling and continuous space exploration, which converts space resources into oxygen and hydrocarbon fuels. The traditional ISRU in outer space mainly uses high temperature and high pressure to electrolyze water or reduce CO₂, having problems such as low conversion efficiency, high energy consumption, and excessive equipment volume. Here, an electrochemical catalytic synthesis technology based on a microfluidic device is proposed, which can convert H₂O and CO₂ into O₂ and organic matter by electrocatalytic method at room temperature and achieve efficient energy and matter conversion. The gas-liquid mixing and electrochemical reaction were analyzed. A mathematical model of gas-liquid two-phase mixing and microfluidic chemical reaction was established. The research results demonstrate the reliability and efficiency of the microfluidic reaction device designed in this paper for ISRU.

Optimum Yield of Empty Fruit Bunches Cellulose Nanofibers by Deep Eutectic Solvent and Ultrasonication

Posted on 24 August 2023 by

Cellulose nanofibers (CNFs) were successfully extracted from empty fruit bunches (EFBs) using deep eutectic solvent (DES) treatment assisted by ultrasonication. DES, a green solvent created by combining choline chloride and oxalic acid dehydrate, was capable to digest EFB cellulose into CNFs, a process which may serve as foundation for high-yield, industrial-scale synthesis of nanocellulose.

Abstract

Cellulose nanofibers (CNFs) are extensively utilized as affordable, renewable materials. The conventional technique for making CNFs is time-consuming, requires hazardous toxic chemicals, and consumes enormous amounts of energy. CNFs from empty fruit bunches (EFB) were produced via deep eutectic solvent (DES) and ultrasonication. The DES treatment conditions were optimized using the central composite design (CCD) approach of response surface methodology (RSM). Analysis of variance (ANOVA) revealed that the reaction time, DES molar ratio, and temperature were all significant variables. The experimental results closely correspond to the theoretical model of CNFs yield. X-ray diffraction (XRD) studies demonstrated that the crystallinity index of the CNFs increased significantly after sonication. It could be stated that DES treatment and ultrasonication were effective ways to successfully generate CNFs from EFB. This study may serve as foundation for high-yield, industrial-scale synthesis of nanocellulose using DES treatment.

Radiation‐Induced Admicellar Graft Polymerization of 2‐Hydroxyethyl Methacrylate onto Polyvinylidene Fluoride Membranes Using an Electron Beam Accelerator

Posted on 23 August 2023 by

The graft polymerization of 2-hydroxyethyl methacrylate onto a polyvinylidene fluoride (PVDF) membrane by admicellar polymerization was accomplished using graft polymerization induced by radiation. Electron beam irradiation was applied to covalently activate more free radicals to graft the copolymer. The effect on the physicochemical properties of PVDF before and after modification was investigated.

Abstract

The efficiency of admicellar graft polymerization in functionalizing polyvinylidene fluoride (PVDF) membranes was explored. The effect of 2-hydroxyethyl methacrylate (HEMA) concentration and the absorbed dose was investigated using a simultaneous method of radiation-induced graft polymerization. The degree of grafting increased with raising the absorbed dose and HEMA concentration. The Fourier transform infrared (FTIR) peak for C–O stretch and the asymmetric and symmetric stretching of the C–O–C bridge, respectively, proved the presence of poly(2-hydroxyethyl methacrylate) (PHEMA) on the modified PVDF. As the grafting yield increased, rougher surfaces were observed. According to contact angle analysis, the grafted membrane with a higher grafting yield outperformed the low grafting yield membrane in terms of water flux and hydrophilicity.