AbstractPyrolysis characteristics of the algae biomass collected from local source in the presence of HZSM-5 catalyst was investigated using Thermogravimetric analyzer (TGA) in this study. Multi-components of carbohydrates, proteins, lipids and other component dissociation in algae sample taking place at different stages at varying temperature condition was confirmed as per the multi-step DTG curve. The average activation energy, and pre-exponential factor for the pyrolysis reaction were analyzed using the isoconversional integral methods such as, Flynn–Wall–Ozawa (FWO), Kissinger–Akahira–Sunose (KAS), and Starnik and Coats Redfern (SCR) methods, and differential isoconversional method of the Kissinger method. The stages of multi-component dissociation was evident consistently in the kinetic and thermodynamic properties analyzed in this study. The diffusion kinetic model fits well into the pyrolysis zone based on the master plot method. The thermodynamic properties including, change in enthalpy, Gibbs free energy, and entropy of the pyrolysis reaction confirms the complex nature of the pyrolysis reaction.

AbstractA focused, brief review on the issue of needleless electrohydrodynamic (EHD) methods for making submicron fibers and particles is presented. Advantages over conventional EHD methods, especially on the issue of production scale, are discussed. An overview of key, entry-point patent, and journal literature are offered to assist the materials processing engineer in the equipment design selection.

AbstractIn this research, proportional-integral (PI) and Fuzzy logic control (FLC) strategies are designed to control wastewater treatment processes at the whole plant level. Two control combination strategies are implemented to minimize the operational cost index (OCI) and effluent quality index (EQI). The benchmark simulation model (BSM2-P) is used as a working platform. In close resemblance to practical operations, the sensors are considered as non-ideal with delay and also having measurement noise. Binary-level control topology is designed in which the lower-level PI controller is used to control the dissolved oxygen (DO) levels in the second aerobic reactor by manipulating the oxygen mass transfer coefficient (KLa) of the last three aerobic reactors and FLC is designed at the supervisory level based on Ammonia levels. Ammonia in the second aerobic reactor is taken as a feedback signal for FLC to compute the DO setpoints. In comparison with non-supervisory control structures, operational cost is improved in PI-Fuzzy by 6.5%. Compared to the open-loop control, the PI controller improves effluent quality by 2.1%. Nevertheless, the combination of PI and fuzzy control shows high greenhouse gas production rates.

AbstractFlare gas recovery is a procedure that reduces the greenhouse gas emissions. Ejectors play a technically efficient and productive role in the recovery of flare gas. The higher the secondary fluid entrainment rate causes better performance of the ejector. The main purpose of the recent study is increasing the flow of gas in the gas recovery ejectors. A two-phase ejector is examined using computational fluid dynamics (CFD) in order to have an optimized performance. The diameter and length of the throat, the nozzle diameter, as well as the converging and diverging angles are the geometrically assigned influence the secondary fluid flux. To achieve the highest entrainment rate, the optimal value of these parameters was determined using the multi-objective genetic algorithm (MOGA) proposed three points as an ejector design candidate. As a result, the rate is improved when a reduction occurred in the length of the throat and the converging angle. It was also increased while reducing the nozzle and throat diameters and the diverging angle. Compared to the basic case, the optimal geometries raised the amount of flow by 25.5, 16.06, and 12.76 times, respectively. Energy efficiency evaluation for the base model and all design points has been made was about 3.5 times higher than the basic case in the second candidate. The first point could also improve the efficiency up to 78%, whereas it was dramatically reduced by the third candidate (47%).

AbstractJosef Stefan developed the theoretical framework needed to analyze the diffusion column in the second half of the 19th century. For the next six decades after his death, his design allowed the estimation of binary gas diffusivities assuming a flat liquid–gas interface and isothermal operation at atmospheric pressure. In the 1950s, inaccuracies in the diffusivity estimates were detected. These were related to column end effects at the top, where turbulence and eddy formation at the mixing point of the sweep and gas phases occurred, and at the liquid–gas interface, where curvature due to surface tension changed the mass transfer area and the diffusion path length for gas A to the top. The present work examines quantitatively for the first time the relationship between interfacial curvature resulting from surface tension and the binary gas diffusivity estimates in the Stefan column. The hypothesis is that such a relationship exists. The dimensionless parameter N1, which gives the ratio of surface tension to gravitational forces acting on the interface, determines the radial distribution profile, in turn affecting the curved-to-flat-interface binary gas diffusivity ratio. The generalized surface tension model was validated numerically with interfacial descent versus time data from two Stefan column runs reported recently (acetone-air and n-hexane-air). The experimental curved-to-flat-interface diffusivity ratio in both runs was 1.7–1.8, indicating an important contribution from interfacial curvature in the diffusivity calculations. The researcher now has a quantitative tool relating interfacial curvature due to surface tension and the binary gas diffusivity estimates obtained in the Stefan column.

AbstractMost of the mediums in the chemical industry exhibit the shear-thinning property, i.e., the effective viscosity decreases with the increasing shear rate. In this work, the effect of shear-thinning property on the vortex structure evolution and induced pressure fluctuation of an axial flow pump is numerically studied. The CMC solution is used as the shear-thinning fluid, and the viscous Newtonian fluid (viscosity equals the apparent viscosity of the shear-thinning fluid as the flow index is 1) is adopted for comparison. The results show that the apparent viscosity variation in the guide vane is more obvious than that of the impeller. In the Newtonian fluid case, two passage vortexes are found in the guide vane passage outlet, but only one larger-scale passage vortex exists for shear-thinning fluid. Meanwhile, the shear-thinning property enhances the interaction between vortices and mainstream, leading to higher pressure fluctuation. Different from the Newtonian fluid case, the rotor-stator interaction and the shear-thinning property play a dominant role in pressure fluctuation, and the shear-thinning property can arouse low-frequency fluctuation components.

AbstractNowadays, renewable and cleaner biofuel requirements increase with the increase in economic, environmental, and social concerns. Biobutanol is a preferable alternative fuel due to its outstanding properties compared to other alcohol-based biofuels. Two alternative downstream process configurations are designed in this study to obtain high-purity alcohol products from isopropanol–butanol–ethanol (IBE) fermentation broth with the same feed flowrate and compositions. In process configuration 1, the excess amount of water in the fermentation broth is mainly taken away using a preconcentration column. In process configuration 2, an extractor-extractive distillation hybrid system is used to remove the excess amount of water from the system. The results show that the first configuration is superior with a 62% reduction in total annual cost (TAC). Besides economic superiority, process configuration 1 is also quantitatively better than process configuration 2 in terms of gas emissions and energy demand to purify butanol. As a result, process configuration 1 is found as an eco-efficient downstream separation sequence for IBE purification process.

AbstractIn the present work, we studied the effect of increasing different emulsifiers concentration on the size distribution of a simple emulsion (O/W) and double emulsion (W/OW). In one hand, we observed that increasing polycaprolactone (PCL) concentration in the O/W emulsion, the size of the droplets decreased. On the other hand, increasing the concentration of polyvinyl alcohol (PVA), pluronic f68 or bovine serum albumin (BSA) as second emulsion stabilizers of the “W/O/W” emulsion led to micrometer size droplets in all cases up to 7 μm. Also, when the concentration of pluronic f68 increased from 1.5% w/v to 6.0% w/v the size distribution of the double emulsion turned from polydisperse to monodisperse. We conclude that the chemical structure of pluronic provide a more stabilizing effect to the emulsion than PVA or BSA. Finally, we studied the inner morphology of the “W/O/W” by Focused Ion Beam technique combined with Scanning Electron Microscopy (FIB-SEM) and confirmed the development of a double emulsion. These results are promising for cosmetics of pharmaceutical applications because it is important to obtain a monodisperse size distribution of the emulsion and a detailed characterization of inner morphology of the microspheres.

AbstractAccurate measurement of solution tracer concentration in residence time distribution (RTD) tests can be difficult in low volumetric flowrate systems where solution must be accumulated over a period before there is sufficient volume for a tracer concentration measurement. This is encountered with laboratory-scale heap leaching column salt tracer RTD tests. Step-up tracer experiments were used to show how this results in tracer concentration underestimation (due to mixing effects) and loss of profile features, such as tracer concentration step changes. A tracer measurement setup was conceived to overcome this. It was designed to have well-defined flow which could be described using a compartment model of a plug flow and well-mixed volume in series. The model was used to calculate “true” tracer concentrations from the measured values (correlation coefficients greater than 0.983). It was demonstrated to be effective at both correcting tracer concentration magnitudes and restoring lost profile features.

AbstractThin-film nanocomposite reverse osmosis (TFN-RO) membranes were fabricated in this study. Titanium silicate-1 (TS-1) was used as an additive during interfacial polymerization. Since nanoparticle dispersion in the membrane matrix is a significant challenge in fabricating high-performance membranes, polyvinyl alcohol/titanium silicate-1 (PVA/TS-1) composite with different PVA polymer dosage was prepared and used in TFN-RO membrane to provide better dispersion of the synthesized TS-1. As a result, the pure water flux increased by 39.5%, and the NaCl rejection improved from 95.03% to 99.1% at the optimum content of 0.1 wt.% (PVA) and 0.1 wt.% (TS-1). The antifouling properties of this membrane for bovine albumin serum (BSA) and humic acid (HA) were enhanced. Characterization of the morphologies of the membranes was investigated using AFM and FESEM. The measurement of water contact angle and zeta potential was accomplished to characterize the surface properties of the membranes. ATR-FTIR was used to study the chemical structure of the membranes. Following the introduction of the PVA/TS-1 composite, the TFN membranes became smoother, thinner, more hydrophilic, and negatively charged. Due to hydroxyl groups and less cross-linked structure of the top layer, water flux was higher. A smoother surface and more negative charges on the top layer also improved fouling resistance.

AbstractThe enhanced oil recovery (EOR) method is widely used for recovering residual crude oil after implementing conventional oil recovery techniques. Chemical additives, such as surfactants, are considered beneficial for EOR. Their efficacy is assessed based on their ability to reduce interfacial tension, modify wettability, and establish a stable emulsion system. Understanding the mechanism of surfactant adsorption at the oil–water interface is critical for effectively implementing surfactant flooding. In this work, we have studied the adsorption of a natural surfactant synthesized from Eichhornia crassipes at the oil–water interface using numerous interfacial analyses. The results show substantial adsorption at the oil–water interface, indicated by a 27% increase in zeta potential (i.e. −25.2 to −37.2 mV) and ∼27 times increase in film elasticity (i.e. G′: 0.15–4.12 Pa at 0.01 Hz frequency and 0.01% strain). The synthesized natural surfactant demonstrates a noteworthy improvement in the stability of the oil-in-water emulsion and interfacial rheological properties, indicating its potential application in EOR.

AbstractRefining vegetable oils generate residues that can be reused to obtain high-value compounds. Tocopherols, phytosterols, and squalene can be recovered from deodorizer distillates using molecular distillation. However, treatment of the deodorizer distillates is required to obtain better separation results. Thus, this work aimed to evaluate the effect of the esterification of a residue composed of mixtures of different types of deodorizer distillates on the efficiency of phytonutrient recovery by molecular distillation. The results showed the best conditions for the esterification were 74 °C, 214 min, 3% H2SO4, and 2:1 molar methanol/free fatty acids ratio. These reaction conditions maintained 97% of total phytonutrients and reduced 90.5% of free fatty acids. Concentration gains for tocopherols (331%), phytosterols (232%), and squalene (300%) were obtained for the esterified residue. Therefore, this work presents an alternative route to obtaining a phytonutrient concentrate by combining steps of esterification and molecular distillation for mixtures of deodorizer distillates.

AbstractDue to superior characteristics, ionic liquids (IL) have become a more environmentally friendly alternative to traditional toxic, flammable, and volatile organic solvents. Protocatechuic acid (PCA) is a widely distributed phenolic acid and a key metabolite of complex polyphenols. It is a molecule that functions as a chemical building block for polymers and plastics as well as has pharmacological effects. The current project’s goal is to enhance the recovery of PCA by IL-based extraction from industrial waste streams and fermentation. This research investigates the separation of PCA from an aqueous stream using Imidazolium-based IL, 1-butyl-3-methylimidazolium octyl sulfate and 1-Hexyl-3-methylimidazolium hexafluorophosphate with an efficiency of about 87% at 10% IL concentration for a PCA concentration of 10 mmol L−1. The influence of the initial PCA concentration and IL concentration on the separation efficiency was also investigated, and various parameters helpful for the design of an industrial separation unit were determined.

AbstractCharacteristic curve equations are used to calculate the products distribution during the non-catalytic aquathermolysis of Ashal’cha heavy crude oil at different reaction times (12, 24, 48, and 72 h) and temperatures (250 and 300 °C) with a 3:7 water-to-oil weight ratio. The developed equations accurately estimate the experimental information at different time of reaction and temperature with average absolute error lower than 5%. Unstable primary and secondary (UPS) products equations predicted the experimental results for aromatics and saturate fractions better than stable primary and secondary (SPS) products equations. On the contrary, the gas fraction was well calculated with the SPS products correlation.

AbstractIn this study, the leaching of sucrose from sugar beet was investigated in a batch process using distilled water solvent. Extraction kinetics was explored at low and high solutions/solid mass ratios. The experimental data were examined by a mathematical model based on Fick’s second law and the Azuara model as a semi-empirical model to determine diffusion coefficients, equilibrium concentrations, and dissociation coefficient K (the ratio of the concentration at the sample to concentration in solution). Diffusion coefficients were calculated by nonlinear regression of the experimental findings. The diffusion coefficients of sucrose (ranging from 2.4831 × 10−10 to 3.2023 × 10−10 m2/s) were higher in the high solution/solid mass ratios compared to the low ratios (ranging from 0.5231 × 10−10 to 0.8728 × 10−10 m2/s) due to higher mass transfer driving force. Also, the proposed empirical Azuara model could properly describe equilibrium concentrations by predicting results (squared mean square error less than 0.0082) close to experimental data at different operating conditions.

AbstractThe increasing contamination of water resources is a severe environmental problem. Manganese is highly soluble in water, has adverse effects on the environment and human health during excessive exposure, and is difficult to remove. Biosorbents have been suggested to remove metals from aqueous solutions, therefore, apple pomace was utilized to prepare activated biochar (activated charcoal from apple pomace, ACAP). The biochar sample was characterized by X-ray fluorescence spectrometry, scanning electron microscopy, thermogravimetric analysis, Fourier transform infrared spectroscopy, and Brunauer–Emmett–Teller analysis. The aim of this study was to use ACAP as an adsorbent to remove Mn2+ ions from aqueous solutions. Adsorption experiments were performed in the pH range 3.2–6.5, with various masses of ACAP biochar and Mn2+ ion concentrations. The results were evaluated using the pseudo-first order, pseudo-second order, general order, Elovich, and Webber and Morris kinetics models. All the models fitted the experimental results, the equilibrium time was 15 min, and the pseudo-second order model presented the highest constant (k2), indicating that chemosorption is an important mechanism in adsorption. The adsorption isotherm results were adjusted using different models, wherein the Langmuir and Temkin models exhibited the best fit to the experimental results. Adsorption experiments yielded a 97.5% removal rate of Mn2+ ions at pH 6.5 and <5% at pH 3.2, and the desorption of manganese in nitric acid (0.1 M) was 97.5%. Overall, apple pomace biochar is an efficient adsorbent for removing Mn2+ ions in aqueous media, and is applicable for treating water for human consumption.

AbstractCO2 enhanced oil recovery (EOR) processes provide the perfect balance to sequester anthropogenic CO2 emissions in the subsurface while continuing to produce crude oil, which due to the lack of suitable alternatives, continues to be the most economically viable fuel for the developing world. Unlike, other eco-sustainable energy sources, oil produced from projects undergoing CO2-EOR emit large volumes of CO2 on combustion. However, this volume of CO2 is certainly lower than oil produced from other projects, yielding a net-zero emission scenario where the amount of CO2 emitted is equal to or lesser than CO2 sequestered in the subsurface. Thus, in this study, various means of CO2-EOR like gas injection, water-alternating gas (WAG), carbonated water injection (CWI) and foam flooding were performed in a fabricated porous media and the resultant oil recovery was compared with the amount of CO2 injected to establish the carbon footprint of each method. From the presented results, the application of foam flooding is recommended to achieve near net-zero carbon emissions from produced crude oil.

AbstractCaffeine (CAF) is a widely used stimulant in beverages, foods, and drugs. Extreme usage of this popular molecule can create caffeine pollution for water sources. A photocatalytic method was developed to degrade CAF in water. The pillared interlayered clays (PILCs) were used as the photocatalytic material. Zeolite, a type of clay, was used to prepare PILCs. The operational parameters, such as reaction time, CAF concentrations, H2O2, and PILCs amounts, were examined to obtain the highest removal percentages. The removal rates reached 97%, 100%, and 100% in 120, 180, and 300 min, respectively, using 1.0 mL H2O2 and 1.0 g of Fe-Ti-PILC for 50.0 mg/L CAF under UV exposure. The experiments were carried out in batch method, and RP-HPLC was used to find the remaining CAF concentrations.

AbstractIn this article, the thermal stability of tert-butyl perbenzoate (TBPB) mixed with different concentrations of toluene and p-tert-butylcatechol (TBC) was investigated. The exothermic onset temperature (T0), the heat of decomposition (ΔH), and the adiabatic temperature rise (ΔTad) of the samples were obtained by differential scanning calorimetry (DSC) and Phi-TEC II adiabatic calorimetry. The apparent activation energy (Ea) and the maximum reaction rate arrival time under adiabatic conditions were obtained by adiabatic kinetic calculations for 8 h (TD8) and 24 h (TD24). Based on Semenov’s theory, the self-accelerated decomposition temperature was calculated as a support for safe storage and transport. The results of DSC and Phi-TEC II showed that toluene was effective in reducing the thermal hazard during the decomposition of TBPB. The addition of TBC caused side reactions. The moderate addition of toluene and TBC improves the thermal stability of TBPB and can improve the safety of TBPB in industrial applications.

AbstractAs an issue of public health, lead pollution has been a major concern for industrialists, environmentalists, and health workers. Researchers are always looking for the best way combat to Pb(II) contamination problem from the wastewater generated by industries. Here a new Schiff base ligand 2-(Piperazin-1-yl)ethan-1-imine methyl benzaldehyde (PEIMB), was constructed and used for the functionalization of chitosan. The magnetized chitosan (MCS-PEIMB) was characterized by FTIR, XRD, SEM, EDX, VSM, and TG techniques. The adsorption process of Pb(II) ions using the prepared adsorbent was investigated by the study of different factors such as pH values, adsorption time, the initial concentration of Pb(II) ions, and adsorbent dosage. The obtained results from Langmuir isotherm proved the monolayer adsorption of Pb(II) ions on the surface of MCS-PEIMB with the maximum adsorption capacity of 142.86 mg/g. The effect of some variables including pH values, adsorption time, and adsorbent dosage was assessed using a central composite design, and 4.02, 31.14 (Min), and 0.1044 (g/L) were obtained as optimum conditions, respectively. In addition, the adsorption mechanism of lead ions on the surface of MCS-PEIMB was studied using Gaussian 09 program package.