International Journal of Chemical Engineering

The present study aims to provide a mathematical model of the Williamson fluid flow via a permeable stretching/shrinking sheet in the MHD boundary layer in the presence of a heat source, chemical reaction, and suction. This study is novel because it investigates the physical effects of thermal and solutal stratification on convective heat and mass transport using thermal radiation. The flow’s PDEs are numerically solved using the BVP4c approach and the pertinent similarity variables until a stable solution is found. Through visual analysis, the effects of dimensionless factors on temperature, velocity, and concentration profiles are examined. This encompasses the mass transfer rate, the heat transfer rate, and the coefficient of friction. The results of the present analysis are found to be consistent with those of previously published studies. The findings demonstrate that enhanced temperature and concentration profiles cause the Williamson, magnetic, and permeability parameters to rise in conjunction with a drop in the dimensionless velocity. In relation to temperature, the thermal stratification parameter exhibits the opposite tendency. Regarding the solutal stratification parameter, concentration profiles are seen to show the opposite trend. Lastly, the current work will have important implications for the removal of dust and viruses from viscoelastic fluid in bioengineering, the medical sciences, and medical equipment.

This research paper focuses on the removal of the nonsteroidal anti-inflammatory drug, ibuprofen, from an aqueous solution using a dissolved air flotation process. The comparison of different types of cationic surface-active agents such as cetyltrimethyl ammonium bromide (CTAB), tetrabutyl ammonium bromide (TBAB), and octyltrimethyl ammonium bromide (OTAB) have been employed to scrutinize the effective removal of the ecotoxic pharmaceutically active compound. The work included the influencing parameters such as pressure, contact time, surfactant dosage, pH, flow rate, and initial concentration owing to the best-optimized conditions. The maximum removal rate of 96.09% was achieved at 15 min for CTAB, TBAB had 62.36% at 45 min, and 89.6% was obtained for OTAB at 30 min, with 50 mg L⁻¹ as the initial concentration and pH = 4. The removal rate was better with the optimized dosage of CTAB at 0.6 g, TBAB at 1.2 g, and OTAB at 1.0 g. It was observed that the geometric shape of the surface-active agents had greater impacts on the contaminants’ efficiency. CTAB and OTAB were combined to find out the best possible removal rate of contaminants. The synergistic effect augments surfactant-based occurrence to be better in forming a good foaming effect and tends to have a lower critical micelle concentration (CMC). From the evaluation of kinetic models, pseudo-second-order flotation kinetics fitted the experimental data best. Furthermore, the formed metabolites that had been identified using gas chromatography-mass spectrometry were found to be less toxic than the parenting compounds.

In recent decades, reports from around the globe indicate an increase in natural organic matters (NOMs) in surface waters, which has a negative impact on drinking water purification and causes problems such as the taste and color of water, reducing the amount of dissolved oxygen in water, causing membrane fouling in the filtration process, and acting as a precursor for the formation of an antiseptic by-product. This work used the adsorption process to evaluate the elimination of natural organic compounds in aquatic environments. Ethylenediaminetetraacetic acid (EDTA) as a crosslinker for chitosan (CTS) and N, N-methylenebisacrylamide as a crosslinker for polyacrylamide (PAM) were used to prepare humic acid (HA) adsorbents utilizing a two-step procedure. The FTIR spectroscopy proved the EDTA cross-linking agent was effective with the semicrosslinking CTS/PAM hydrogel. CTS/PAM/EDTA double network (DN) hydrogel exhibited a higher HA adsorption capacity ( = 107.7 mg/g) than CTS/PAM ( = 59.3 mg/g) at pH = 7 and an initial concentration of 60 mg·L⁻¹ during 60 min. Also, results demonstrate that CTS/PAM/EDTA DN hydrogels showed faster adsorption kinetics than CTS/PAM.

The effect of inside surface baffle installation conditions on the minimum impeller rotational speed for just the drawdown of floating solid was investigated. The inside surface baffle condition is the condition in which a partial baffle is placed with a clearance between the baffle and the vessel wall. In this study, a baffle with an insertion length of 0.2 times the liquid height was used. Moreover, the effect of baffle angle on was investigated. The was measured visually at least three times. The results showed that the effect of the radial installation position of the inside surface baffle on depended on the impeller position. In addition, even baffles placed parallel to the tangential flow were found to decrease .

This work depicts that rice straw (RS), which is one of the major lignocellulosic wastes all over the world and causing many environmental problems, has considerable amounts of protein, ash, macronutrients, and micronutrients of approximately 11.38%, 16.77%, 2.27 mg/kg, and 771.9 mg/kg, respectively; besides, a C/N ratio of 15.18, a total N, P₂O5, and K₂O content of 1.85%, and a considerably low concentration of undesirable heavy metals and silica of approximately 77.69 mg/kg and 109 mg/kg are also present, which recommends its applicability as a precursor feedstock for the production of organic fertilizer and animal fodder. The batch solid-state fermentation (SSF) of RS by Trichoderma longibrachiatum DSMZ 16517 produced considerable amount of total reducing sugars (TRS) of approximately 339.2 mg TRS/g RS under the optimum operatic conditions of 20% (w:v) substrate concentration, pH 7, 1% inoculum size, a 9-day incubation period, and 30°C incubation temperature. The readily available and cost-effective agroindustrial waste, sugarcane molasses, proved to enhance the fungal biomass growth and (hemi) cellulolytic enzymes activities. The inoculated RS-SSF batch process with T. longibrachiatum precultured on 10% molasses enhanced the (hemi) cellulolytic enzymatic activities and TRS production rate by approximately 5.82 and 3.8 folds, respectively, relative to that inoculated by T. longibrachiatum precultured in the conventional potato dextrose broth medium. The separate hydrolysis and fermentation processes by different yeast strains Candida tropicalis DSM 70156, C. shehatae ATCC 58779, and Saccharomyces cerevisiae ATCC 64712 revealed an efficient bioethanol yield and productivity that ranged between 0.36 and 0.38 g/g sugars and 0.22 and 0.23 g/L/h, respectively, with concomitant competent fermentation efficiencies that ranged between 48.35% and 51.25%. The proximate analysis of rice straw before and after fungal hydrolysis proved calorific values of approximately 15.8 MJ/kg and 16.05 MJ/kg, respectively, recommending their applicability as primary and secondary solid biofuels. Thus, this study proved the waste prosperity of RS for environmental opulence and sustainability.

Electrically heated tobacco products (EHTPs) could release effective aerosol components from tobacco materials at relatively low temperatures without a burning phenomenon. It is essential to grasp the temperature distribution and release mechanism of key components in heated tobacco materials. The existing experimental studies have provided initial insights into the thermodynamic behavior of tobacco materials under various conditions. However, current numerical models are still in their early stages of development, with the majority failing to correlate heat transfer with component release. Based on this, a coupled numerical model of gas flow, heat transfer, and the release of key components in the electrically heated tobacco product is established in this study, which exhibits improvements in revealing the internal heat and mass transfer characteristics in the porous media of tobacco and is capable of evaluating the influence of component contents and product design parameters. The release rates of water, glycerol, and nicotine components are quantitatively described by the first-order Arrhenius formula, and the transport of heat and gas flow is simulated using the Navier-Stokes equation. The accuracy of the model is validated through experiments, including temperature monitoring at multiple measurement points and determination of residual contents in the tobacco substrate after each puff. The simulation results suggest that an appropriate component ratio and tobacco filler mass can enhance both the release amount and release efficiency of key components, and reducing either the diameter or length of the tobacco section can help to improve the heat transfer performance. A slower heating rate matched with longer preheating times enables the complementary release of water and glycerol components, which helps to regulate the uniformity of component content in the aerosol to some extent. This study helps to provide suggestions for the design and optimization of electrically heated tobacco products.