Linear Driving Force Model Research Articles

CONSTRUCTAL DESIGN APPROACH FOR CARBON DIOXIDE ADSORPTION SYSTEMS

Current carbon capture and storage (CCS) benchmark technologies and materials are both energy and economically costly. Therefore, it hopes to rely on uncovering combinations of designs or materials to provide the performance leap to scale up the CCS deployment to meet the most optimistic Intergovernmental Panel on Climate Change (IPCC) projections and socioeconomic shared pathways to mitigate global warming. While the search for advanced materials for carbon capture has drawn much of the efforts to enhance the so-called productivity (CCPr), i.e., CO2 mols per volume of CC material per cycle for high levels of purity for CO2 recovery, there is an opportunity to investigate before-hand how those materials would fare energy wise (PE) (total energy expenditure by total amount of CO2 mols captured) in the reactor. This work presents a formulation based on the Constructal Theory to explore how the features of the materials themselves (absorptivity, molecular diffusivity, density), the packing (pellets shape and size, effective diffusivity, specific capturing rate, porosity), and the configuration of a column packed-bed reactor affects the energy penalty (PE). The investigation is theoretical and numerical by modeling the CO2 mass balance in a prescribed and constant mobile phase flow rate (initially CO2-rich exhaust gases) isothermal 1d tubular packed-bed reactor and the coupling with CO2 mass balance at the pellet level with linear driving force model – both are saturated porous media. The simulations were performed using newly developed Python code and commercial software. The model was turned nondimensional, and the influence of the adapted Peclet and Damkhöler numbers was explored, which showed reverse trends in the indices CCPR and PE. It showed the trade-off between the resistances to adsorb CO2 and the other features of the reactor’s design, providing insights into how those systems may evolve.

Comprehensive study on copper adsorption using an innovative graphene carbonate sand composite adsorbent: Batch, fixed-bed columns, and CFD modeling insights

Comprehensive study on copper adsorption using an innovative graphene carbonate sand composite adsorbent: Batch, fixed-bed columns, and CFD modeling insights

Exploring the potential of Desert Rose fibers (Adenium obesum) for the remediation of oil-contaminated sites

Exploring the potential of Desert Rose fibers (Adenium obesum) for the remediation of oil-contaminated sites

Elucidating the dynamics of carbamazepine uptake using date pit-derived activated carbon: A comprehensive kinetic and thermodynamic analysis

Water contamination with pharmaceuticals such as Carbamazepine (CBZ) presents a significant environmental challenge. This study investigates the use of activated carbon derived from waste date pits (DPAC) for the removal of CBZ from water. The impact of several parameters such as pH, temperature, CBZ concentration, and flow rate on the adsorption were assessed. The generated DPAC demonstrated a specific surface area of 309m2/g, a pore volume of 0.264cm³/g, and the pores are mainly distributed at 1.86, 2.73, and 3.43nm. The Langmuir, Freundlich, Sips, and Toth isotherms were used to fit the experimental data, and the results indicate the occurrence of monolayer adsorption and heterogeneous surface conditions. The Linear Driving Force model was used for kinetic analysis, showing improved fit at higher concentrations. Thermodynamic analyses revealed the process to be endothermic, spontaneous, and entropically driven. The DPAC achieved an adsorption capacity of 14.89mg/g and maintained 94% effectiveness after the first regeneration cycle and 70% after four cycles. This study highlights the potential of DPAC as a sustainable adsorbent for advanced water purification.

Kinetics of Water Adsorption in Metal-Organic Framework(MOF-303) for Adsorption Cooling Application

Kinetics of Water Adsorption in Metal-Organic Framework(MOF-303) for Adsorption Cooling Application

Mixed-Mode Adsorption of l-Tryptophan on D301 Resin through Hydrophobic Interaction/Ion Exchange/Ion Exclusion: Equilibrium and Kinetics Study.

The adsorption of l-tryptophan (l-Trp) was studied based on the hydrophobic interaction/ion exchange/ion exclusion mixed-mode adsorption resin D301. Firstly, the interaction mode between l-Trp and resin was analyzed by studying the influence of pH variation on the adsorption capability and the dissociation state of l-Trp. Secondly, the adsorption mechanism was illuminated by studying the adsorption equilibrium and kinetic behaviors. The adsorption equilibrium and a kinetics model were constructed. The augmentation of pH gradually elicited an enhancement in the adsorption capacity of l-Trp. l-Trp existing in varied dissociation states could be adsorbed by the resin, and the interaction mode relied upon the pH of the solution. An integrated adsorption equilibrium model with the coadsorption of different dissociation states of l-Trp was developed and could predict the adsorption isotherms at various pH levels satisfactorily. Both external mass transfer and intra-particle diffusion collectively imposed constraints on the mass transfer process of l-Trp onto the resin. An improved liquid film linear driving force model (ILM) was constructed, and the model provided a satisfactory fit for the adsorption kinetics curves of l-Trp at various pH levels. l-Trp molecules had a high mass transfer rate at a relatively low solution pH.

Multicomponent mass transfer modeling of antagonistic binary adsorption of metallic pollutants from water using helical fixed-bed columns

Multicomponent mass transfer modeling of antagonistic binary adsorption of metallic pollutants from water using helical fixed-bed columns

Migration of l-Selenomethionine in the Water-Soil Interface Dominated by Iron Oxides.

Organic selenium (Se) accounts for up to 10-80% of total Se in soils, and l-selenomethionine (SeMet) is a typical organic Se species. However, the migration of SeMet in soils remains elusive. This study investigated the solid-liquid distribution, adsorption, desorption by phosphate, and self-oxidization of SeMet in solution under the influence of ferrihydrite, goethite, and hematite through batch experiments. Iron oxides could adsorb a much larger amount of SeMet than inorganic Se. At the initial Se element concentrations of 0-200 mg/L, the solid/liquid partition coefficient of SeMet was constant, which was 0.41, 0.43, and 0.50 on ferrihydrite, goethite, and hematite, respectively. In addition, the adsorption process of SeMet on the three iron oxides could be well described by the linear driving force model. Accordingly, the intraparticle diffusion coefficient of SeMet in ferrihydrite, goethite, and hematite was 1.4 × 103, 7.9 × 104, and 1.2 × 105 nm2/min, respectively. The adsorption of SeMet on the three iron oxides was slightly influenced by the pH and the coexisting ions, such as Cl-, NO3-, SO42-, and H2PO4-. The desorption ratio of SeMet on the three iron oxides by phosphate was lower than 2.5%. SeMet would aggregate the nanoparticles of iron oxides, resulting in a synergistic effect on the adsorption of phosphate. The oxidization ratio of SeMet was 23.9% in the solution, while it decreased to 17.1-17.5% in iron oxide suspensions. For this oxidization process, the three iron oxides exhibited varying effects to decelerate SeMet oxidation, as represented by the equivalent reaction. The findings of this study reveal the migration of SeMet in the water-soil interface under the influence of iron oxides, which can improve the understanding of Se cycling in the environment as well as provide some guidance for the better utilization of Se in soils and environmental remediation of Se pollution.

Hygroscopicity in Epoxy Powder Composites

Epoxy powders offer a low-cost way of manufacturing thick-section composite parts, such as those found in wind and tidal turbines. Currently, their processing cycle includes a lengthy drying stage (≥15 h) to remove ambient moisture. This drying stage prevents void defect formation and, thereby, a reduction in mechanical properties; however, it constitutes up to 60% of the processing time. Little research has been published which studies the drying stage or its optimisation. In the present work, experimental and simulated analyses are used to investigate the effects of hygroscopicity in epoxy powder composites. Tests are performed to quantify the void content of dried and undried laminates and to measure its impact on transverse flexural strength. Dynamic vapour sorption analysis is used to study the sorption behaviour of the epoxy powder. It is shown that the epoxy powder is slightly hygroscopic (1.36 wt%) and exhibits sorption behaviour that is characteristic of glassy polymers. This results in up to 4.8% voids (by volume) if processed in an undried state, leading to a 43% reduction in transverse flexural strength. A modified linear driving force model is fitted to the desorption data and then implemented in existing process-simulation tools. The drying of a thick epoxy powder composite section is simulated to investigate the influence of powder sintering on the duration of the drying stage. Process simulations reveal that a standard drying cycle prematurely sinters the powder, which inhibits moisture release. By maintaining the powder state, simulations show that the drying cycle can be reduced to 5 h.

Removal of antibiotics, bacterial toxicity, and occurrence of antibiotic resistance genes in secondary hospital effluents treated with granular activated carbon and the impact of preceding chlorination

This comprehensive investigation highlighted the complex adsorption behaviors of antibiotics onto granular activated carbon (GAC), the effectiveness of this adsorption in reducing bacterial toxicity, and the reduction of antibiotic resistance genes (ARGs) and antibiotic resistant bacteria (ARB) in hospital wastewater (HWW) effluents. Six GACs were characterized for their physicochemical properties, and their ability to adsorb six antibiotics in the background matrix of actual HWW was evaluated. Coconut shell-derived GAC (Co-U), which had the highest hydrophobicity and lowest content of oxygen-containing acidic functional groups, demonstrated the highest adsorption capacities for the tested antibiotics. Bacterial toxicity tests revealed that GACs could eliminate the bacterial toxicity from antibiotic intermediates present in chlorinated HWW. By contrast, the bacterial toxicity could not be removed by GACs in non-chlorinated HWW due to the greater presence of intermediate components identified by LC-MS/MS. The intraparticle diffusion coefficient of antibiotics adsorbed onto Co-U could be calculated by adsorption kinetics derived from the linear driving force model and the homogenous intraparticle diffusion model associated with the linear adsorption isotherms (0-150μg/L). Meropenem and sulfamethoxazole exhibited the highest adsorption capacities in a single-solute solution compared to penicillin G, ampicillin, cetazidime, and ciprofloxacin. However, the greater adsorption capacities of meropenem and sulfamethoxazole disappeared in mixed-solute solutions, indicating the lowest adsorption competition. GAC can eliminate most ARGs while also promoting the growth of some ARB. Chlorination (free chlorine residues at 0.5mg Cl2/L) did not significantly affect the overall composition of ARGs and ARB in HWW. However, the accumulation of ARGs and ARB on GAC in fixed bed columns was lower in chlorinated HWW than in non-chlorinated HWW due to an increase in the adsorption of intermediates.

A comprehensive study on the kinetics and isotherms of D2/H2 adsorptive separation using pure and composite Cu-BDC-NH2 MOFs at 77 K

A comprehensive study on the kinetics and isotherms of D2/H2 adsorptive separation using pure and composite Cu-BDC-NH2 MOFs at 77 K

A sustainable approach to combat industrial air pollution using commercially available and engineered gas-phase adsorbents

A sustainable approach to combat industrial air pollution using commercially available and engineered gas-phase adsorbents

Activated Carbon as an Adsorbent for CO2 Capture: Adsorption, Kinetics, and RSM Modeling.

The main objective of this research is to investigate the adsorption isotherms and the optimization of the carbon dioxide (CO2) adsorption process on activated carbon (AC). The AC has been characterized by X-ray diffraction, scanning electron microscopy, and nitrogen (N2) adsorption-desorption. The CO2 isotherms measured under three adsorption temperatures (318, 308, and 298 K) were investigated by the Langmuir and linear driving force model. It is found that the Langmuir model could well predict the adsorption behavior of AC with a correlation factor of about 0.99. The kinetic model shows that the amount of CO2 increases at higher pressures. The response surface methodology (RSM) was applied to investigate the effects of process variables and their interaction on the response to reach the optimal conditions. Based on the analysis of variance, pressure and temperature are the main factors influencing the CO2 adsorption capacity. The effective parameters obtained through this model are found to have a value of p < 0.05. In addition, a semiempirical correlation was developed under the optimal operating conditions which are 25 °C and 9 bar. The results indicated that RSM models provide an effective method for evaluating CO2 adsorption. These results point that AC is a potential adsorbent for CO2 capture.

Enhanced adsorption of bisphenol-A from water through the application of isocyanurate based hyper crosslinked resin

Enhanced adsorption of bisphenol-A from water through the application of isocyanurate based hyper crosslinked resin

Assessment of the new kinetically limited linear driving force model for predicting diffusion limited adsorption breakthrough curves

Assessment of the new kinetically limited linear driving force model for predicting diffusion limited adsorption breakthrough curves

Transient mass and heat transport modeling in a multi-tray packed bed solid desiccant dehumidifier: A parametric analysis

Transient mass and heat transport modeling in a multi-tray packed bed solid desiccant dehumidifier: A parametric analysis

HEMA-based macro and microporous materials for CO2 capture

HEMA-based macro and microporous materials for CO2 capture

Continuous Biosorption of Pb2+ with Bamboo Shoots (Bambusa spp.) using Aspen Adsorption® Process Simulation Software

The health risks impact of heavy metal contamination in the environment has prompted researchers to study its mitigation in an efficient and cost-friendly approach. Recently, simulated continuous biosorption using agricultural wastes is gaining popularity because it offers cheaper and faster alternative study methods using efficient large-scale removal of lead, which is known to cause adverse effects even at low concentrations. Bamboo shoots (Bambusa spp.), a delicacy known in Southeast Asia, are recognized worldwide, but the inedible sheath husks are thrown. This study evaluated the continuous Pb2+ biosorption performance of Bambusa spp. using Aspen Adsorption V8.4 by varying bed height, influent concentration, and volumetric flow rate. Linear driving force model was used to simplify, according to a separate batch biosorption study, ion exchange mechanism and Langmuir isotherm for equilibrium conditions. The backward differencing method was used to solve the resulting differential equation. Results showed that increasing the volumetric flowrate from 4.00x10-5 to 8.00x10-5 m3/s, the bed height from 0.2 to 1.0 m, and influent concentration from 80 to 120 ppm resulted in changes in the breakthrough time by a factor of 0,5, 4.0, and 0.67 respectively. Analysis of the breakthrough curves showed that increasing volumetric flow rate shortens breakthrough time due to reduced contact time, and increasing Pb2+ concentration facilitated ion exchange by increasing concentration difference. Bed height provides more binding sites available hence, higher Pb2+ removal.

A mathematical model for ammonium removal and recovery from real municipal wastewater using a natural zeolite

A mathematical model for ammonium removal and recovery from real municipal wastewater using a natural zeolite

Mass and Heat Transfer of Pressure Swing Adsorption Oxygen Production Process with Small Adsorbent Particles

Rapid-cycle pressure swing adsorption (PSA) with small adsorbents particles is intended to improve mass transfer rate and productivity. However, the mass transfer mechanisms are changed with reduction of particle size during rapid-cycle adsorption process. A heat and mass transfer model of rapid-cycle PSA air separation process employing small LiLSX zeolite particles is developed and experimentally validated to numerically analyze the effects of mass transfer resistances on the characteristics of cyclic adsorption process. Multicomponent Langmuir model and linear driving force model are employed for characterizing the adsorption equilibrium and kinetic. The results of numerical analysis demonstrate that the dominant mass transfer resistance of small adsorbents particles is a combination of film resistance, axial dispersion effect and macropore diffusion resistance. The oxygen purity, recovery and productivity of the product are overestimated by ~2–4% when the effect of axial dispersion on mass transfer is ignored. As particle size decreases, the front of nitrogen-adsorbed concentration and gas temperature become sharp, which effectively improves the performance. However, the adverse effect of axial dispersion on the mass transfer becomes significant at very small particles conditions. It is nearly identical shapes of nitrogen concentration and gas temperature profiles after adsorption and desorption steps. The profiles are pushed forward near the production end with an increase in bed porosities. The optimal oxygen recovery and productivity are achieved with a particle diameter of 0.45 mm and bed porosity of 0.39 during the PSA process.