Kinetic Model Research Articles

Application of Ce2(WO4)3-ZnO-CuO Nanocomposite as Active Photocatalyst for Removal of Ciprofloxacin from wastewater

In this study, Ce2(WO4)3/ZnO/CuO nanocomposite (NCs) was prepared by using Co-precipitation method and its synthesis was confirmed by using X-ray diffraction (XRD), Scanning electron microscopy (SEM), Differential reflectance spectroscopy (DRS) and Fourier transform infrared spectroscopy (FTIR) analysis. The degradation efficiency for photocatalytic degradation of Ciprofloxacin (CF) and band gap value of prepared Ce2(WO4)3/ZnO/CuO nanocomposite was determined by using UV-Visible and DRS analysis. Band gap value for Ce2(WO4)3/ZnO/CuO was found to be 1.39 eV. Effects of different parameters such as contact time, pH, and effect of concentration of catalyst were investigated to optimize degradation conditions. This prepared nanocomposite was used for the degradation of CF and about 91% degradation efficiency of CF has been achieved at pH 5 within 70 min by irradiation under sunlight and 60 mg concentration of photocatalyst. The EDTA and IPA scavenged photo-generated holes and hydroxyl ions respectively, the decrease in photocatalytic degradation indicates that holes and hydroxyl ions are reactive species in photocatalytic degradation of CF. The value of R2 = 0.99 confirms the validity of Pseudo first order and Langmuir-Hinshelwood kinetic model for the degradation of CF. These results showed a novel method for the preparation of nanocomposite and the efficient degradation of antibiotics and can be applied to industrial manufacture.

Synthesis and characterization of pH-responsive sodium alginate/humic acid composite hydrogels for sustained drug release of l-ascorbic acid

Addressing the challenges of poor biocompatibility and degradability of artificial drug carriers and poor stability of natural monomer gels in the current pharmaceutical market, this study utilized green natural sodium alginate (SA) and humic acid (HA) as raw materials. SA/HA-Ca2+ hydrogel spheres were prepared using Ca2+ as a crosslinking agent and loaded with l-ascorbic acid (L-AA), and the drug-retardation study was conducted using the droplet method. Various analysis techniques confirmed the formation of a three-dimensional network structure through coordination between HA, SA, and Ca2+, resulting in hydrogel spheres with good thermal stability. Meanwhile, the drug-loading rate, swelling, and in vitro drug release of SA/HA-Ca2+ gel spheres were investigated. Results showed that the hydrogel spheres exhibited strong pH responsiveness and satisfactory pore structure favorable for the loading of L-AA. The solubility of the SA/HA-Ca2+ hydrogel in buffer solutions at pH = 1.4 and 7.4 was 1.7315 and 5.1235 g/g, respectively, while the swelling kinetics followed a second-order swelling kinetic equation; the maximum release of L-AA was 23.67 % and 82.64 %. The release profiles of L-AA from different drug-loaded gels conformed to Langmuir's quasi-primary and quasi-secondary kinetic models. In conclusion, this study provides a theoretical basis for achieving slow drug release using SA/HA-Ca2+.

Co-transport of citrate-modified biochar nanoparticles and released plant-available silicon in saturated porous media: Effect of LMWOAs and solution chemistry

Citrate-modified biochar nanoparticles (CBCNPs) represent a promising amendment with plant-available silicon (PASi) releasing capacity. However, the co-transport behavior with released PASi remain poorly understood. This study investigated their co-transport in saturated porous media under various solution chemistry and low molecular weight organic acids (LMWOAs). Experimental and two-site kinetic model results revealed that higher ionic strength caused favorable aggregation and size-selective, hindering CBCNPs transport. Divalent Ca2+ ions retained CBCNPs more effectively than K+ due to stronger charge screening and cation bridging. The pH buffering capacity of CBCNPs resulted in consistent transport behavior across a broad pH range (4-8). XDLVO calculation clarified the impact mechanisms of IS, ion types and pH on CBCNPs transport. Furthermore, LMWOAs exhibited a time-dependent blocking effect on CBCNPs transport. Oxalic acid (OA) and citric acid (CA) facilitated CBCNPs transport though mechanisms beyond XDLVO, including steric hindrance, competitive adsorption, and surface hydrophilicity. The presence of LMWOAs significantly hindered PASi co-transport, with the inhibitory effect ranked as acetic acid (AA) ≈ CA > OA > absence of organic acids. The inhibition is attributed to the blocking effect and formation of Si-organic acid complexes, as evidenced by breakthrough curves and density functional theory calculations. This study provides novel insights into the co-transport of CBCNPs with released PASi through mutual mechanisms, indicating both potential environmental benefits and risks.

P03-12 Physiologically based kinetic modelling (PBK) using QIVIVE to predict the toxicokinetic profiles of triazoles via oral route of administration

P03-12 Physiologically based kinetic modelling (PBK) using QIVIVE to predict the toxicokinetic profiles of triazoles via oral route of administration

A Kinetic-magnetohydrodynamic Model with Adaptive Mesh Refinement for Modeling Heliosphere Neutral-plasma Interaction

The charge exchange between the interstellar medium and the solar wind plasma is crucial for determining the structures of the heliosphere. Since both the neutral-ion and neutral–neutral collision mean free paths are either comparable to or larger than the size of the heliosphere, the neutral phase space distribution can deviate far away from the Maxwellian distribution. A kinetic description for the neutrals is crucial for accurately modeling the heliosphere. It is computationally challenging to run three-dimensional time-dependent kinetic simulations due to the large number of macroparticles. In this paper, we present the new highly efficient Solar Wind with Hydrogen Ion Exchange and Large-scale Dynamics-2 model with a kinetic model of neutrals and a magnetohydrodynamic model for the ions and electrons. To improve the simulation efficiency, we implement adaptive mesh refinement and particle splitting and merging algorithms for the neutral particles to reduce the particle number that is required for an accurate simulation. We present several tests to verify and demonstrate the capabilities of the model.

Response of Fennel (Foeniculum vulgare) plants to the application of acidified biochar and its impact on phosphorus release utilizing kinetic models

Response of Fennel (Foeniculum vulgare) plants to the application of acidified biochar and its impact on phosphorus release utilizing kinetic models

Macadamia Nut Residue-Derived Biochar: An Eco-Friendly Solution for β-Naphthol and Reactive Black-5 Removal

The generation of liquid waste containing dyes and complex organic compounds is a problem in the textile industries. In this work, we evaluated the use of macadamia nut residue as a precursor of a biochar for the treatment of these effluents through the adsorption process. The macadamia nut endocarp undergoes a sequential treatment involving pyrolysis at 600 °C followed by physical activation with CO2 and H2O vapor at 700 °C. Characterization of the resulting macadamia nut residue-derived biochar (MB) is accomplished through various techniques, including X-ray diffractometry (XRD), thermogravimetric analysis (TGA), scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDS), nitrogen physisorption analysis and the pH at the zero charge point (pHZCP). Performance studies reveal that pH exerts minimal influence on the adsorption phenomenon. The Elovich kinetic model effectively describes the adsorption kinetics for both β-naphthol and reactive black 5 (RB5), with adjusted coefficients of determination (R2adj) of 0.99 and 0.94, respectively. Further analysis using the intraparticle diffusion model demonstrates that β-naphthol adsorption kinetics involve multiple mechanisms, while RB5 adsorption is predominantly governed by intraparticle diffusion. Equilibrium adsorption data for both adsorbates fit well with the Sips isothermal model, yielding maximum adsorption capacities of qmax β-naphthol = 15.16mg∙g-1 and qmax RB5 = 3.08mg∙g-1 at 55 °C. The adsorption process for both compounds is spontaneous and endothermic, based on the enthalpy values, it can be inferred that the β-naphthol adsorption is governed by weak van der Waals forces, indicating physisorption. As for RB5, the enthalpy value suggests that the phenomenon occurs due to electrostatic interactions between the molecule and the surface groups with higher energy involved. This study highlights the potential of macadamia nut residue biomass as a precursor for biochar, demonstrating its favorable attributes for application as an effective adsorbent material in the removal of organic compounds such as β-naphthol and RB5 from wastewater streams within the textile industry.

Model-driven design and validation of glucose supply control in a tubular photobioreactor operated under oxygen-balanced mixotrophy

Scaling up bioprocesses remains challenging due to the partially unpredictable and suboptimal behavior of microbes during scale transition. Mathematical modelling serves as a valuable tool in navigating these challenges. In this study, we developed and validated a kinetic model based on the tank-in-series approach for a novel bioprocess known as oxygen-balanced mixotrophy with the microalga Galdieria sulphuraria. This model aims to facilitate the design of an effective glucose feeding control strategy tailored for two-phase tubular photobioreactors (TPBRs). The residence time distribution of our reference reactor was investigated by means of a tracer experiment. Qualitative analysis of the results indicated that our system was optimally represented by simulations with a 100 stirred-tank reactors (STRs).The controlled variable, oxygen concentration in the gas phase, showed a downward trend in simulations with simplified conditions: fixed oxygen production and balanced glucose supply. The decrease was caused by dominant net heterotrophic activity and accumulation of CO2 in the gas phase. Different configurations of a proportional-integral-derivative (PID) controller were designed by means of the ultimate gain method and compared under these simplified conditions. The most effective PID controller was implemented and refined in simulations with outdoor weather conditions. The model was validated successfully by simulating over time in a lab-scale STR the spatial fluctuations happening in a TPBR. The empirical oxygen consumption and production were faster and steeper than in the model, probably due to inaccuracies in parameter estimation or biomass adaptation.

Preparation of Cu-doped MIL-125(Ti)-derived carbon-based composites for the sonodynamic degradation of organic dyes

Sonocatalysis provides a green and sustainable strategy to remove industrial organic pollutants. Toward improving the sonocatalytic performance to remove the organic dyes, a new Cu-C@TiO2 catalyst was prepared via doping the Cu(II) ions into the MIL-125(Ti) and then carbonizing the resultant Cu-MIL-125(Ti) in this study. By the SEM, EDS and BET, the obtained Cu-C@TiO2 was a porous carbon-based hybrid with bimetallic centers, retaining a large amount of organic frameworks to supply adequate specific surface area for the adsorption; By the XPS and UV–vis DRS, the band gap of Cu-C@TiO2 was reduced to significantly broaden the light absorption region and facilitate the separation of electron-hole pairs; By the fluorescence spectra, the graphite-like structure and Cu particles produced on the catalyst surface served as an electron trap to inhibit the recombination of charge carriers. The Cu-C@TiO2 showed an excellent sonocatalytic performance to organic dyes, and under the ultrasound irradiation (35 KHz, 150 W), it could remove more than 95 % of rhodamine B (5.00 mg/L) and methylene blue (5.00 mg/L) within 10 min. By the kinetic analysis, it was found that the dye removal obeyed the first-order kinetic model, and the scavenging studies of free radicals (OH and O2−) verified the Cu-C@TiO2-mediated sonodynamic degradation was in the dye removal. In the end, a Cu-C@TiO2-mediated adsorption/sonodynamic degradation mechanism was proposed to thermodynamically expound the removal process of organic dyes.

P05-31 PBK modelling concepts for a user friendly generic bovine kinetic modelling platform to predict transfer of compounds from feed, veterinary medicines and supplements to food

P05-31 PBK modelling concepts for a user friendly generic bovine kinetic modelling platform to predict transfer of compounds from feed, veterinary medicines and supplements to food

Experimental investigation and statistical analysis of the microwave drying process on the physical properties of Y2O3–Al2O3–ZrO2 composite ceramic powder

Y2O3–Al2O3–ZrO2 composite ceramic powders are an important structural and functional material. The agglomeration problem in the ceramic powder drying process must be resolved to prepare high-quality ceramic powder, and choosing the right drying techniques can significantly lessen ceramic powder agglomeration. Y2O3–Al2O3–ZrO2 ceramic powder was dried using microwave drying. The drying kinetics of the powders were examined with their initial mass, moisture content, and microwave power. As microwave power, beginning moisture content, and initial mass rose, the average drying rate also increased, according to the experimental data. To better characterize the microwave drying process, the drying data were fitted and analyzed using four thin-layer drying kinetic models, namely Quadratic Model, Modified Page, Wang and Singh, and Two-term exponential. The outcomes demonstrate the good fitting effect of the Modified Page model and the compliance of the fitting parameters with the law. The samples before and after drying were characterized by Fourier transform infrared spectroscopy. Calculating the diffusion coefficient by Fick's second law shows that the effective diffusion coefficient of Y2O3–Al2O3–ZrO2 composite ceramic powder is 5.6 × 10−11 m2/s when the initial moisture content is 5%, the microwave heating power is 560 W, and the initial mass is 25 g. The activation energy for microwave drying of Y2O3–Al2O3–ZrO2 ceramic powders was calculated to be 22.83 W/g according to the Arrhenius formula. This paper aims to provide a theoretical basis and rich experimental data for the study of microwave drying of Y2O3–Al2O3–ZrO2 composite ceramic powder.

Whole-cell biocatalysis for phthalate esters biodegradation in wastewater by a saline soil bacteria SSB-consortium

Phthalic acid esters (PAE) are widely used as plasticizers and have been classified as ubiquitous environmental contaminants of primary concern. PAE have accumulated intensively in surface water, groundwater, and wastewaters; thus, PAE degradation is essential. In the present study, the ability of a saline soil bacteria (SSB)-consortium to degrade synthetic wastewater-phthalates with alkyl chains of different lengths, such as diethyl phthalate (DEP), di-n-butyl phthalate (DBP), benzyl butyl phthalate (BBP), and di (2-ethylhexyl) phthalate (DEHP) was characterized. A central composite design-response surface methodology was applied to optimize the degradation of each phthalate, where the independent variables were temperature (21–41 °C), pH (5.3–8.6) and PAE concentration (79.5–920.4 mg L−1), and Gas Chromatography-Mass Spectrometry was used to identify the metabolites generated during phthalate degradation. Optimal conditions were 31 °C, pH 7.0, and an initial PAE concentration of 500 mg L−1, where the SSB-consortium removed 84.9%, 98.47%, 99.09% and 98.25% of initial DEP, DBP, BBP, and DEHP, respectively, in 168h. A first-order kinetic model explained - the biodegradation progression, while the half-life of PAE degradation ranged from 12.8 to 29.8 h. Genera distribution of the SSB-consortium was determined by bacterial meta-taxonomic analysis. Serratia, Methylobacillus, Acrhomobacter, and Pseudomonas were the predominant genera; however, the type of phthalate directly affected their distribution. Scanning electron microscopy analysis showed that high concentrations (1000 mg L−1) of phthalates induced morphological alterations in the bacterial SSB-consortium. The metabolite profiling showed that DEP, DBP, BBP, and DEHP could be fully metabolized through the de-esterification and β-oxidation pathways. Therefore, the SSB-consortium can be considered a potential candidate for bioremediation of complex phthalate-contaminated water resources.

Adsorption and kinetic studies of dyes onto BaFe12O19 Ferrite Nanoparticles

Abstract In this work, Barium hexaferrite (BaFe12O19) nanoparticles were used for industrial waste water treatment from methylene blue (MB) and congored (CR) dyes. Batch adsorber with mechanical stirring column was used to test various experimental parameters like contact time, initial dye concentration and adsorbent dosage for the removal of these dyes. For the removal of MB and CR dyes using magnetic nanoparticles, the maximum adsorption capacities were 200 and 124.5 mg/g respectively. The maximum removal efficiencies were 90 % for MB removal onto the nanoparticles and 80% for CR removal. In order to analyze the kinetic data, pseudo first and second order kinetic models have been used. For all studied variables and based on correlation coefficient (R) values and graphical presentation, the results confirm that pseudo second order model fits well the experimental data.

Thermal-mechanical-chemical coupled model and three-dimensional damage evaluation based on computed tomography for high-energy laser-ablated CFRP

High-energy laser is widely used for machining carbon fiber reinforced polymer (CFRP) composites because of their high precision and fine quality. However, the mechanism by which CFRPs are damaged by high-energy laser in processing is unclear. In this article, the coupled mechanism of laser-ablated CFRPs is investigated experimentally and theoretically. The three-dimensional morphology of laser-damaged CFRPs is captured by computed tomography (CT), which quantitatively characterizes the degree of pyrolytic charring and internal delamination. Accordingly, a thermal-mechanical-chemical coupled model is established considering the matrix pyrolysis, pyrolysis gases flow, sublimation of the charring layer and mechanical failure. The progressive loss of solid media and the inhomogeneous deformation of CFRPs are incorporated into the traditional ablation kinetic model, making it possible to describe the damage to CFRPs caused by both chemical reactions and thermal stress. The predicted damage morphology is consistent with the experimental results, revealing the generation of internal defects due to the synergistic effects of interlaminar tensile stress and matrix pyrolysis. Additionally, the effects of charring layer sublimation, laser power and process time on damage responses are analyzed, and the real-time evolution of damage degree is investigated.

Optimization of Rhizoclonium hieroglyphicum extract for enhanced synthesis of nickel oxide nanoparticles using response surface methodology and its potential exploration in biological application.

The study investigates the potential of Rhizoclonium hieroglyphicum as a novel source for synthesizing nickel oxide nanoparticles (RH-NiONPs) and evaluates its biological applications. Phytochemicals in the algal extract serve as capping, reducing and stabilizing agent for nickel oxide nanoparticles. The process variables were optimized using BBD based RSM to obtain maximum RH-NiONPs. Characterization of RH-NiONPs using UV-Vis and FT-IR spectroscopy reveals the plasmon resonance peak at 340 nm and the functional groups responsible for reduction and stabilization. XRD confirmed the crystalline nature while the stability and size of the RH-NiONPs were determined by DLS and zeta potential. Toxicity assessments demonstrated the effect of RH-NiONPs against Vigna radiata, Allium cepa and Artemia salina was low. RH-NiONPs revealed significant zone of inhibition against the selected bacteria and fungi. The results of larvicidal activity showed that RH-NiONPs are toxic to 4th instar larvae of Daphnis nerii. Also, RH-NiONPs efficiently decolorized Reactive Violet 13 (92%) under sunlight irradiation and the experimental data well fits to Langmuir isotherm along with pseudo second order kinetic model. The thermodynamic studies enunciate the exothermic and non-spontaneous photocatalytic decolorization of reactive violet 13. Thus, the current study assesses the eco-friendly and cost-effective nature of RH-NiONPs along with its biological applications.

Reutilization recovered nutrients from wastewater by synthesizing eco-friendly slow-release hydrogel fertilizer for sustainable vegetable production

Recovering and reusing resources from waste is a practical necessity for realizing sustainable development, while the lack of arable land and speedy release of fertilizer is also an urgent issue required to improve soil water and fertilizer conditions. Here, an eco-friendly biodegradable hydrogel was fabricated to serve as a slow-release carrier for nutrients that recovered from wastewater and investigated the potential role of it on vegetable growth. The hydrogel owned excellent water swelling and retention capacity, while degraded by more than 50 % within 11 weeks. Electrostatic interactions, hydrogen bonding, and ion exchange dominate the binding between nutrients and hydrogel, thus contributing to the maximum release period and efficiency for nitrogen, phosphorus, and potassium was 74.28 % in 21 days, 88.28 % in 28 days and 72.52 % in 7 days, respectively. Kinetic model fitting and molecular dynamics simulations indicated that the Fickian diffusion controls the release of fertilizers. Vegetable yields and root elongation were significantly improved by applying the slow-release hydrogel fertilizer, with yield increases up to more than two-fold at the second round of cultivation. Overall, this work provides novel insights into the reutilization of high-value resources from wastewater and agriculture sources to support a stable food supply.

Model development and process evaluation for algal growth and lipid production

Microalgae grabbed the attention worldwide because of their application in renewable energy with a number of environmental benefits such as carbon dioxide assimilation to produce biofuel. In this study, a kinetic model aiming to analyze algae growth and lipid production was developed. Biomass was divided into two parts, algae residual cell and lipid, to analyze their kinetics distinctively and to find out the inside process mechanism. The model was calibrated and validated with different experimental datasets, varying carbon sources, and phosphate concentrations. The capability of the model to predict the dynamics of algal culture over a broad range of growth conditions was investigated. The presence of acetate reduced the bicarbonate uptake for algal growth and growth on organic carbon was higher compared to that of carbon dioxide. The presence of ammonium showed a very strong inhibition effect on algae and lipid production rate but enhanced lipid content. Phosphate caused both limitation and inhibition effects on algae growth and lipid production rate. The maximum growth was found at 12 mg/L PO43- concentration and 3.10 mg/L NO3--N concentration. Lipid content was enhanced by limiting phosphate. Overall, the developed model allows optimizing of nutrient concentrations and operating conditions specifically to enhance lipid productivity.

Utilization of macadamia nutshell-derived activated carbon for enhanced congo red adsorption

This study addresses the challenge of removing Congo red (CR) from aqueous solutions using activated carbon (AC) derived from macadamia nutshells (MNS). A unique two-step carbonization and pyrolysis process was employed to produce MNS-AC with high surface area and porosity. Key experimental variables, including initial CR concentration, contact time, and pH, were systematically varied in batch mode. Results indicated that the modified AC achieved significantly higher removal percentages compared to unmodified charcoal. At pH 2.0 and an initial dye concentration of 50 mg L−1, CR removal reached 97.48 % for MNS-AC3. The maximum adsorption capacity (qmax) of 58.29 mg g−1 was observed at an initial dye concentration of 200 mg L−1. The pseudo-second-order kinetic model closely matched the experimental data, and equilibrium data analysis using Langmuir and Dubinin-Radushkevich (D-R) isotherm models provided excellent fits. This research demonstrates the potential of using industrial biomass waste to develop sustainable solutions for dye removal in wastewater treatment.

Towards maximization of parameters identifiability: Development of the CalOpt tool and its application to the anaerobic digestion model

This work addresses the need for robust approaches to estimate kinetic parameters in continuous anaerobic co-digestion plants. Specifically, it outlines a procedure for including data from batch activity tests on digestate samples, in addition to the poorly informative dataset from conventional monitoring of biogas facilities. To profitably make use of activity tests, the estimation of the biomass composition in digestate samples is required to improve parameters identifiability. To this purpose, an open-source tool (CalOpt) was developed and tested on a pilot-scale co-digester, simultaneously using data from both conventional monitoring and lab-scale activity tests. Targeting the prediction of volatile fatty acids (VFAs) concentrations in the digestate of the continuous co-digester, the kinetic parameters of different microbial groups were selected for calibration based on parameters importance ranking and collinearity index. The results demonstrate that the CalOpt tool significantly improved the fitting of acetic, propionic, and butyric acid concentrations in digestate as well as the methane flowrate from the digester. Furthermore, the study assessed the necessity of modifying the Monod kinetics to account for substrate inhibition by incorporating the Haldane term in the VFAs uptake kinetic model, which proved to be essential for better interpreting batch activity tests.

Biomass-based Perovskite/Graphene Oxide Composite for the Removal of Organic Pollutants from Wastewater

Water pollution is a critical issue that affects both human health and the environment. Biomass-based LaFeO3 is prepared by the microwave-assisted method using rice straw as a cellulose source. Then LaFeO3/graphene oxide (GO) composite is prepared by ultrasonication to facilitate the perovskite-GO binding. Raman and FTIR spectra of the prepared composite identify the presence of the perovskite, biochar, cellulose and GO oxide phases and proves the surface functional groups interactions. Transmission electron microscope image shows that the GO sheets are homogeneous covered with the perovskite nanoparticles. The adsorption performance of the LaFeO3/GO composite for the removal of methylene blue (MB) and congo red (CR) dyes from aqueous solution is optimized. Adsorption follows pseudo 2nd order kinetic model and Freundlich isotherm, with maximum adsorption capacities of 319.5 and 416.7 mg/g for MB and CR, respectively. These values are higher than those reported for magnetic GO composites, indicating the excellent adsorption ability of the proposed perovskite/GO composite. A thermodynamic study shows that the adsorption of MB is exothermic, while it is endothermic for CR and combines physisorption and chemisorption characteristics for both dyes. The proposed adsorbent shows a good performance in the presence of NaCl interferent, with the possibility of regeneration and efficient successive reuse.