Chemical Engineering Journal Advances最新文献

This study evaluates the effectiveness of iron-modified biochar (Fe-BC) in fixed-bed heterogeneous Fenton processes for levofloxacin (LFX) removal, a widely-used fluoroquinolone antibiotic. The objective is to optimize parameters such as pH, oxidants (H₂O₂ and S₂O₈²⁻), and biochar forms (functionalized and raw) using factorial analysis of mixed data (FAMD) and response surface methodology (RSM). These optimizations identified the ideal conditions for maximal LFX removal. The most effective removal with Fe-BC occurred at 2.5 mM H₂O₂ and pH 7.5, while the optimal S₂O₈²⁻ conditions were 1.6 mM at pH 2.8. Both Fe-BC and raw biochar (RBC) showed the highest adsorption at pH 5.8. In adsorption-only, RBC and Fe-BC reduced LFX to 530 μg/L and 335 μg/L, respectively, in 60 min. The oxidation process further decreased LFX levels to between 8.9 μg/L and 0.1 μg/L using S₂O₈²⁻ and H₂O₂, respectively. The research expanded upon a kinetic model, incorporating the calculation of kinetic constants for both adsorption and oxidation processes, to deepen our understanding of the intricate degradation dynamics at play. Identifying by-products was crucial in elucidating degradation pathways. These findings are vital for environmental remediation, demonstrating the efficiency of Fe-BC in removing harmful antibiotics from water. This research highlights the potential of modified biochar in environmental clean-up, especially for water contaminated with antibiotics. The results emphasize the importance of optimizing treatment conditions for effective antibiotic removal, contributing valuable insights to the field of environmental remediation.

Constructing the reliable dynamic sensitivity profile for the output variable using the machine learning model is a challenging task; however, the dynamic sensitivity trends are helpful to understand the impact of the input variables on the system's performance. In this paper, we have derived the partial-derivative approach-based sensitivity analysis expression for the non-linear auto regressive with exogenous (NARX) model for the first time. The engineering systems-based case studies, i.e., two distillation columns with five and ten stages, respectively are taken which are commonly found in the chemical processing plants. Two output variables, i.e., liquid composition in tray 2 and tray 4 (Y₂ and Y₄) of a five-stage distillation column, and liquid composition in tray 7 (Y₇) of a ten-stage (higher) distillation column are modelled by NARX with respect to time, feed concentration (X_f) and feed flow rate (L_f). The dynamic sensitivity profiles of the output variables with respect to X_f and L_f for the two distillation columns are plotted by the derived partial derivative-based sensitivity expression on the NARX model. Furthermore, the forward difference method of sensitivity analysis (first principle method) is also applied on the ordinary differential equations of the distillation columns to compute the sensitivity values of the output variables. A good agreement in the dynamic sensitivity values of the output variables with respect to the input variables is found for the two sensitivity analysis techniques thereby demonstrating the effectiveness of the partial-derivative approach for the improved NARX's interpretability performance. This research presents the explicit partial-derivative based sensitivity analysis expression for the NARX model which can be utilised for time-series applications and can provide the insights about the model's interpretation performance.

Advanced oxidation process (AOPs) technologies are the subject of intense research due to the need for treating refractory wastewaters. Among them, hydrodynamic cavitation (HC) is particularly well-studied because of its potential as an AOP and as a means of intensification for other processes, including other AOPs. Understanding HC and its effects is crucial for its development and practical application. This study introduces a conceptual model that integrates the presence of supercritical water (SCW) to interpret HC results. The model was validated by selected experimental scenarios focused on exploring the impact of HC on the viscosity of a soluble polymer solution, the precipitation of an ionic salt from an unsaturated solution, and the stripping of volatile organic compounds (VOCs). The results were analyzed and interpreted using the conceptual model, remarking the scenarios that cannot be explained by the generally accepted mechanisms of radicals’ formation or pyrolysis. Furthermore, the model was then applied to analyze the trends reported in the existing literature regarding the application of HC as an AOP and as a method of intensification. The occurrence of SCW as a key driving force for HC chemical and physical effects represents a novel approach with the potential to enhance the design and operation of HC systems, particularly when tailoring operating conditions to maximize SCW occurrence.

The study of an inclined stretching cylinder in a porous medium holds significant implications for understanding complex fluid dynamics and heat transfer phenomena, mainly when influenced by a hybrid nanofluid containing Cu and Al₂O₃, Joule heating, and a magnetic field in the presence of Williamson fluid. The nonlinear ordinary differential equations are derived by applying pertinent similarity transformations to partial differential equations. Subsequently, these non-dimensional ordinary differential equations are transformed into a system of first-order ODEs and numerically solved using Maplesoft's symbolic computation software MAPLE 2023. The influence of governing parameters on dimensionless velocity, temperature, concentration, skin friction, heat, and mass transfer rates is investigated. This investigation is crucial for various practical applications, including geothermal reservoirs, enhanced oil recovery, and environmental processes involving porous media. It is demonstrated that Biot and Eckert numbers and nanofluid parameters contribute to increased surface temperature, while the Lewis number leads to a decrease in dimensionless concentration. Moreover, the curvature parameter is associated with an increase in dimensionless concentration, and skin friction demonstrates a direct relationship with the magnetic parameter while inversely correlating with the cylinder's curvature.These results contribute to the scientific understanding of these complex interactions and provide valuable insights for engineering applications, such as designing efficient heat exchangers, optimizing cooling systems, and advancing technologies involving fluid flow and magnetic fields.

The present work demonstrates the performance of hollow fibre membranes fabricated using polyvinyl chloride, polystyrene (EPS) and polydimethylsiloxane (PDMS) coupled with 30% monoethanolamine (MEA) in a gas liquid membrane contactor (GLMC) for the absorption of carbon dioxide. A gas mixture with a composition of (50/50 v/v%) methane (CH₄) and (CO₂) was used to assess the efficiency of the prepared membranes in the removal of carbon dioxide. Then HFM 3 which showed high CO₂ removal was used to separate a mixture of nitrogen (N₂)/oxygen(O₂)/carbon dioxide (CO₂) with a composition of (73/18/9 v/v%), respectively. Four different absorption liquids: 30 % MEA solution, 30 % EDA solution, 30 % MEA – graphene oxide (GO) and 30 % EDA-GO nanofluids were coupled with HFM3 to analyse the efficiency of the different amine liquids in CO₂ absorption in GLMC. The 30 % EDA-GO solution showed an increase in the efficiency of CO² absorption. The nanofluids showed an enhancement factor for CO₂ absorption in the nanofluid was 121 % and 117 % for MEA-GO and EDA-GO, respectively. This enhancement was attributed to the hydrodynamic effects and Brownian motion of graphene oxide in the amine liquids. 30 % EDA solution infused with 0.2 mg/ml graphene oxide nanoparticles achieved the highest loading of carbon dioxide 0.25 mol/ cm³.

In the present study, the density and viscosity of the CO₂-loaded and –unloaded base solution and nano-fluid were experimentally measured and investigated from an intermolecular point of view. Nano-fluids are composed of nano-particles such as Al₂O₃ (0.1 wt.%), Silica-2-methylimidazole, zinc salt (Si-ZIF-8) (0.02 wt.%), and super activated carbon (SAC) (0.1 wt.%) dispersed in aqueous and hybrid Methyl diethanolamine context (MDEA, 40 wt.%) +Sulfolane (SFL), 30 wt.%) +H₂O) Experimental measurements were carried out at the low-temperature ranges 303.15–315.15 K, atmospheric pressure, and three different CO₂ loadings. The results show that nanomaterials do not have a significant effect on the density and viscosity of the unloaded suspension; however, the density and viscosity of loaded suspensions and base solvent become more by increasing CO₂ concentration. In the case of CO₂-loaded fluids, the comparison of the results in the presence and absence of nanoparticles shows that the density of the solution is not much different in the two cases, but the viscosity of CO₂-loaded in Si-ZIF-8, SAC, and γ-Al₂O₃ base nano-fluids in comparison with base solvent shows an increase of 35 % in high CO₂ loading, ∼0.3 mol CO₂ per mol MDEA. Density and viscosity experimental data were modeled using the Genetic Programming approach. The highest values of absolute average relative deviation (AARD) and root mean square error (RMSE) parameters obtained for modeling data are 3.04 and 0.317, respectively, and the lowest value of regression coefficient (R²) is 0.995, which indicates the appropriate fitting of the results.

The gold standard for recovering residual organochlorine pesticides from wastewater and aqueous environmental matrices is the continuous liquid-liquid extraction (CLLE) technique that requires methylene chloride (CH₂Cl₂) as solvent at its refluxing temperature. In light of a recent USEPA proposed prohibitions and workplace protections for CH₂Cl₂ (due to its toxicity) and the fact that CLLE requires expensive and hard-to-acquire glassware, an alternative to CLLE as currently practiced is needed. The bottle liquid-liquid extraction (BLLE) technique, demonstrated for extracting semi-volatile organic contaminants from surface water, is potentially a low cost and high throughput alternative for such recovery. BLLE is cheaper and has a smaller laboratory footprint. The technique, performed at ambient temperature in a tightly capped bottle, requires less amount of solvent and contains solvent vapor within the bottle. The latter means less CH₂Cl₂ is encountered in the workplace. In this study, BLLE was performed directly in 1-L amber sampling bottles and shown to recover 21 organochlorine pesticides as efficiently as CLLE from influents and effluents of two wastewater treatment plants Because no statistical differences were found between CLLE (mean = 77.4, SD = 9.28) and BLLE (mean = 79.1, SD = 14.3); t(22) = 0.548, p(same mean) = 0.58, even though CLLE recovered more pesticides than BLLE by 5.18 ± 8.15%, these techniques are amenable to interchangeable usage. The systematic bias so far detected fits the expression BLLE = 1.4[CLLE] – 35 (r = 0.88). Both CLLE and BLLE recoveries were consistently higher for 4,4′-DDD and lower for aldrin, heptachlor and endrin aldehyde. Diethyl ether addition, as some suggested, did not improve BLLE.

Synopsis: There is need to find a cheap, reliable and high throughput technique for purifying SVOCs from aqueous environmental media efficiently. BLLE, a little known technique, fulfils this need.

Water pollution is a significant global environmental concern that threatens the sustainable progress of humanity. In this study, the concepts of photocatalytic oxidation in the cathodic zone (NH₄⁺-N adsorption-NH₃-N conversion) and electrochemical oxidation in the anodic zone (NH₄⁺-N direct oxidation + chlorination) were proposed to remove ammoniacal nitrogen, and experimental studies were conducted. The stirring of the test solution during the reaction process enhanced the ammoniacal nitrogen removal efficiency by ∼9% after 90 min of reaction. The removal efficiency of ammoniacal nitrogen was comparatively high at low concentrations. After 60 min of reaction in the presence of 15 mg·L⁻¹ ammonium chloride, the removal efficiency exceeded 95%; the removal efficiency of ionized ammonia increased with increasing current density. After 60 min, the removal efficiency of ammoniacal nitrogen exceeded 80%. Under the same ammoniacal nitrogen concentration conditions, the ammoniacal nitrogen removal efficiency in the test solution increased with the increase in the chlorine ion concentration, and in the absence of chlorine ions, ammoniacal nitrogen removal in the electrochemical reaction environment was insignificant. Under the same power and light conditions, the photoelectrochemical reaction exhibited a ∼15% higher ammoniacal nitrogen removal efficiency than electrochemical oxidation.

The study investigated the use of zwitterion-grafted polyethersulfone (PES) membranes integrated with polyelectrolyte coagulation process for the remediation of sewage wastewater after physical screening stage from a wastewater treatment plant (WWTP). The zwitterion (sulfobetaine methacrylate, SBMA) brushes were grafted onto the PES polymer backbone using free radical polymerisation in aqueous medium to improve its hydrophilic properties and therefore reverse its fouling tendencies. The successful synthesis of poly(sulfobetaine methacrylate-grafted PES (pSBMA-g-PES) polymer composite was confirmed using FTIR and TGA, as well as gravimetric method. The resulting polymer composites were used to fabricate zwitterion-containing membranes using the non-solvent induced phase separation (NIPS) method. The performance parameters of the fabricated membranes were all enhanced, i.e., pure water flux, fouling resistance, improved quality of produce water, as well as increased mechanical strength. The observed fouling resistance improved with increasing zwitterion content demonstrating its role in delaying or inhibiting foulant adhesion. The fabricated membranes were used to treat sewage water from WWTP, the results indicating improved performance with increasing zwitterion content. In order to further reduce fouling and increase the useful lifespan of the membranes, pretreatment of the sewerage water with alum was integrated with the filtration process. This was repeated in a six filtration-wash cycles to demonstrate increased reusability of the membranes with improved fouling profile. The produce water qualities was evaluated using pH, turbidity, TDS, TOC, and EC, which were all below the standards required for reuse. The incorporation of zwitterions resulted in increased membrane hydrophilicity and surface charge modulation that explain their comparatively higher antifouling and rejection qualities in comparison to the pristine membrane. The zwitterionic membranes also showed exceptional flux stability and recyclability, indicating a longer lifespan potential.

This work aimed to develop the continuous 5-HMF production process from cane syrup for pharmaceutical applications. A catalyst-free process and a non-toxic solvent were implemented to achieve a cost-effective production process with considerations of safety and environmental impacts. This work studied the roles and influences of various non-toxic organic solvents on production performance and cost. The most common effective solvent (methyl isobutyl ketone) was used as a benchmark. The effects of various operating conditions on the 5-HMF yield and 5-HMF productivity were investigated and optimized based on an experimental design using the most suitable solvent selected. The 5-HMF yield of 66.8 % and 5-HMF production rate of 9.35 × 10⁻⁶ kg/h were achieved under the reaction temperature of 190 °C, residence time of 80 min, syrup feed concentration of 25 g/L, and organic-to-aqueous volumetric ratio of 1:1. The satisfactory 5-HMF yield and reasonable 5-HMF production were observed when compared to other processes obtained from the literature. The feasibilities for improving this process was also discussed.