Dynamic Adsorption Behavior Research Articles

Methane upgrading on pelletised Maxsorb activated carbon by gas-phase simulated moving bed

To study the separation of methane and nitrogen mixtures by gas-phase simulated moving bed (SMB), Maxsorb activated carbon was pelletised by extrusion with 10% binder. Both argon and carbon dioxide were used as potential desorbent gases. The effectiveness of the adsorbent was assessed by analysing the adsorption equilibrium data and conducting fixed-bed experiments to determine the single and multicomponent dynamic adsorption behaviour. Pure component N2, CH4, Ar, and CO2 isotherms were measured at three different temperatures, up to 2.5 bar, using a volumetric method. The results show that CO2 exhibits the highest affinity to the solid phase, followed by CH4, N2, and Ar. Single, binary, and ternary fixed-bed experiments were performed, allowing the validation of the proposed mathematical model. Two SMB cycles were designed to separate a CH4/N2 mixture using each desorbent gas. The respective separation regions were drawn. Both processes achieved a high purity level for the methane stream (above 99%) and exhibited high recovery (above 97%). The obtained results were crossed with the previously studied BPL material, and the Maxsorb adsorbent showed better performance overall.

Structural and functional properties of proteins isolated from four species of microalgae and their application in air-water interface stabilization

Herein, we extracted proteins from four microalgae: Chlamydomonas reinhardtii (CHR), Euglena gracilis (EUG), Spirulina platensis (SPP), and Spirulina maxima (SPM). Subsequently, their physicochemical and functional properties, as well as air-water interface adsorption behavior were investigated. Results demonstrated that the solubility and emulsifying properties of these proteins were significantly affected by pH, with minimum values observed near their isoelectric point (3.5) and maximum values at pH 11.0. Interestingly, the emulsifying properties of the four proteins were superior to soy protein isolate in the pH range of 3.0–7.0, indicating that these microalgae proteins may be suitable for applying as emulsifiers in foods. EUG exhibited the highest water/oil binding capacity, emulsifying activity, and emulsifying stability, which were attributed to its high surface hydrophobicity and β-sheet content, as well as small particle size. Dynamic adsorption behavior analysis illustrated that EUG showed faster diffusion and rearrangement rates, as well as a higher final equilibrated surface pressure value, contributing to its highest foaming capacity and foaming stability. This study greatly enhances the understanding of microalgae proteins and is expected to establish a theoretical foundation for developing novel protein resources that can be utilized in the foamed and emulsion-based food fabrication, including whipped cream and functional beverages.

Pioneering SubPc-Br/CdS S-scheme heterojunctions: Achieving superior photocatalytic oxidation through enhanced radical synergy and photocorrosion mitigation

For the efficient harnessing of solar energy and mitigation of environmental pollution, the development and application of semiconductor photocatalysis technology is paramount. Herein, a novel SubPc-Br/CdS supramolecular array with an S-scheme heterojunction was synthesized through the intermolecular π-stacked self-assembly of subphthalocyanine (SubPc-Br) and nanometer cadmium sulfide (CdS). This self-assembly system features a highly structured architecture and excellent stability. Experiments and ground-state differential charge calculations demonstrate that SubPc-Br and CdS form a built-in electric field during the self-assembly process, a critical factor in promoting the dissociation of electrons and holes. Additionally, this study utilized time-dependent density functional theory (TDDFT) to simulate the dynamic adsorption behavior of excited oxygen molecules on the SubPc-Br/CdS interface for the first time. The analysis of molecular charge differential density under different excited states proved that the addition of SubPc-Br molecules not only improves the photocorrosion resistance of CdS in an O2 adsorption environment but also enhances the production of advanced reactive oxygen species under the synergistic action of h+ and ·O2–. When subjected to visible light, the degradation efficiency of minocycline (MC) achieved 96.8% within 60 min and maintained 80.3% after 5 cycles. In summary, this study highlights the feasibility of creating advanced S-scheme heterojunction photocatalysts through the strategic incorporation of organic supramolecules with semiconductor catalysts.

Comparison and development of the descriptive model with polynomial structures to fit multi-component dynamic breakthrough curves with roll-up, stepwise, and saddle-shaped structure

Dynamic breakthrough curves with roll-up, stepwise, and saddle-shaped structures have been commonly observed in the adsorption/separation process, but could be rarely described by the descriptive model, which limits further analysis and explanation of the breakthrough data. In this work, two new descriptive models, including a general polynomial logistic equation (GPLE) and a general polynomial Gompertz equation (GPGE) are developed to correlate these roll-up, stepwise, and saddle-shaped breakthrough curves. Their correlation coefficients (R2) between the descriptive model and breakthrough data are higher than 0.95, indicating the good applicability of the two descriptive models. Taking some difficult-to-fit literature data as an example, by adjusting these characteristic parameters, six types of breakthrough curves can be fitted by the GPLE or GPGE model. Representatively, satisfying N=2.0, a1≠a2 or b1≠b2, CN<0 or CN<1.0 (∑1NCN=1.0), various roll-up or stepwise breakthrough curves could be fitted accurately. If N=3.0, the GPGE model could explain the multiple roll-up, the multiple stepwise, and the saddle-shaped breakthrough curves. As a result, two new descriptive models can be easily used by workers in various fields to analyze and calculate breakthrough data. Although some reasonable physical explanations need to be explored in the future, they will provide a modeling basis for studying multi-component dynamic adsorption behavior.

Effect of oil structure on adsorption behavior of emulsifier at the oil-polyol interface and the emulsion features

The aim of this study was to investigate the effect of oil structure on the dynamic adsorption behavior of emulsifier at the oil-polyol interface and the corresponding emulsion feature. Glycerol was used as the representative polyol, and the emulsifier was Polyglyceryl-2 Dipolyhydroxystearate (PGPH). Three kinds of alkanes and three kinds of ester oils were chosen for investigation. Firstly, the properties of each oil were studied by measuring surface tension (σ), interfacial tension with glycerol (γ0), and affinity between oils and PGPH. The results indicated that there was little difference in the fundamental characteristics of oils, with the exception of GTCC. Due to its triglyceride structure, GTCC exhibited similar polarity to glycerol, resulting in low interfacial tension and a strong affinity with PGPH. Secondly, the interfacial critical micelle concentration (CMCIFT), saturation adsorption amount (Γ∞), Langmuir constant (κ) and minimum molecular area (Amin) of PGPH were obtained by measuring the dynamic interfacial tension of PGPH adsorption at different oil-glycerol interfaces. The experimental results indicate that for alkanes, the longer the alkane chain length and the more the number of branch chains, the higher the emulsifier Γ∞ at the interface, leading to improved emulsion stability. In ester oils, the greater the affinity between the oil and glycerol, resulting in the lower the initial interfacial tension, a smaller Γ∞ and consequently smaller emulsion particle size. However, this also led to poor emulsion stability. Finally, Pearson correlation analysis was conducted between oil properties, adsorption parameters and emulsion size and stability. The results indicated that for alkanes, there was a negative correlation between particle size and emulsion stability with surface tension and Γ∞. In ester oils, there was a strong positive correlation between particle size and interfacial tension as well as κ. Additionally, the creaming of emulsions showed a strong negative correlation with interfacial tension and Γ∞.

PH-Responsive removal of dyes from wastewater using MXene composited L-Cysteine-grafted HEMA hydrogel: Dynamics, selectivity, regeneration and mechanism

In this work, a MXene composited cysteine-grafted hydroxyethyl methacrylate hydrogel (PHGC/MXene) was successfully synthesized, exhibiting excellent cycle stability and high selectivity toward ionic dyes at different pH. In mixed dyes system, PHGC/MXene exhibited remarkable adsorption selectivity and excellent property of pH-responsivenes for methyl blue (AB93) at pH=2.0 and for methylene blue (MB) at pH=11.0, with maximum adsorption capacity of 207.47 mg/g and 555.56 mg/g, respectively. Even after 12 desorption-regeneration cycles, the removal rates for AB93 and MB remained above 90 %. The study further analyzed the dynamic fixed-bed adsorption behavior of PHGC/MXene for MB, revealing optimal conditions at an inlet concentration of 75 mg/L MB dye and a bed depth of 9 cm. The adsorption mechanism was proposed combined with molecular dynamics simulations. PHGC/MXene emerges as an easily synthesized, highly selective adsorbent with significant potential for the purification of dyes from wastewater in both strongly acidic and strongly alkaline environments.

Phosphatidylcholine Surface Hydration-Dependent Adsorption to Mucin Enhances Intestinal Mucus Barrier Function.

The crucial role of zwitterionic phosphatidylcholines (PC) within mucus gel is essential for maintaining intestinal homeostasis, while the underlying mechanism remains incompletely understood. Herein, we compared the dynamic interfacial adsorption behavior of saturated dipalmitoylphosphatidylcholine (DPPC) and unsaturated dioleoylphosphatidylcholine (DOPC) to intestinal mucin and their impact on the intestinal mucus barrier function. Results of quartz crystal microbalance with dissipation showed that the highly surface-hydrated DPPC vesicles exhibited significantly faster and more extensive adsorption to purified intestinal mucin than the slightly surface-hydrated DOPC vesicles. Utilizing an intestinal Caco-2/HT29-MTX coculture model, we observed that DPPC vesicles adsorbed much more to the mucus gel compared to DOPC vesicles. Additionally, DPPC vesicle adsorption displayed increased wetting, and converse for DOPC vesicles. Interestingly, both of them exhibited nearly the same protective effects against cell injury induced by peptic-tryptic digests of gliadin (PTG). The partial mechanism involved the binding of PTG to DPPC and DOPC within the mucus gel, thereby restricting PTG contact with the underlying epithelial cells. These findings shed light on the intricate interfacial dynamics of PC adsorption to mucin and their implications for maintaining the integrity of the intestinal mucus barrier.

Unveiling the Role of Hydrophobicity on Multilayer Carbon Nanosheets Enriched in sp2-Carbon for Toluene Adsorption under Humid Conditions.

Carbon materials are regarded as a promising adsorbent for the adsorption of volatile organic compounds (VOCs). However, their adsorption behaviors are usually compromised at ambient conditions, attributed to the competitive VOCs adsorption with water vapor. In this study, we demonstrated that the selectivity for toluene than water of carbon can be effectively enhanced by introducing more sp2-carbon with two-dimensional nanosheets stacked. The multilayer carbon nanosheets enriched with sp2-carbon (CNS-MCA) exhibit a 151° H2O-contact angle, indicating hydrophobicity. Dynamic adsorption behaviors revealed that CNS-MCA retain 71% of their toluene adsorption capacity (91 mg/g) even at 60% relative humidity. Density functional theory (DFT) calculations, static adsorption studies, in situ Raman spectroscopy, and time-resolved in situ nuclear magnetic resonance (NMR) spectroscopy collectively indicate that toluene exhibits enhanced adsorption and selectivity due to π-π* interactions between its aromatic rings and the sp2-carbon. Conversely, water adsorption is attenuated, attributed to the reduced availability of surface-exposed hydrogen bonds associated with sp2-carbon and the inherent hydrophobic nature of multilayer graphene. This study extends a novel solution for the enhancement of VOCs adsorption under humid conditions.

A kinetics-coupled multi-surface complexation model deciphering arsenic adsorption and mobility across soil types

The diversity of soil adsorbents for arsenic (As) and the often-overlooked influence of manganese (Mn) on As(III) oxidation impose challenges in predicting As adsorption in soils. This study uses Mössbauer spectroscopy, X-ray diffraction of oriented clay, and batch experiments to develop a kinetic coupled multi-surface complexation model that characterizes As adsorbents in natural soils and quantifies their contributions to As adsorption. The model integrates dynamic adsorption behaviors and Mn-oxide interactions with unified thermodynamic and kinetic parameters. The results indicate that As adsorption is governed by five primary adsorbents: poorly crystalline Fe oxides, well crystalline Fe oxides, Fe-rich clay, Fe-depletion clay, and organic carbon (OC). Fe oxides dominate As adsorption at low As concentrations. However, at higher As concentrations, soils from carbonate strata, with higher content of Fe-rich clay, exhibit stronger As adsorption capabilities than soils from Quaternary sediment strata. The enrichment in Fe-rich clay can enhance the resistance of adsorbed As to reduction processes affecting Fe oxides. Additionally, extensive redox cycles in paddy fields increase OC levels, enhancing their As adsorption compared to upland fields. This model framework provides novel insights into the intricate dynamics of As within soils and a versatile tool for predicting As adsorption across diverse soils.

Th(IV) adsorption by heulandite–high-temperature activated sodium zirconium phosphate from aqueous solution

Herein, heulandite–high-temperature activated sodium zirconium phosphate (HEU–HTA-Na-ZrP) composites were first synthesised for adsorbing tetravalent thorium (Th(IV)) from aqueous solution. Furthermore, the HEU–HTA-Na-ZrP pellets (HEU–HTA-Na-ZrP-P) were fabricated for dynamic adsorption. Compared to Na-ZrP, the BET surface area of HEU–HTA-Na-ZrP increased of ∼ 189 m2⋅g−1. In batch adsorption, Th(IV) adsorption increased with increasing pH, C0 values (initial concentrations) and temperature. The equilibrium Th(IV) adsorption capacities were 314.17 ± 11.27 mg⋅g−1 and 358.89 ± 3.47 mg⋅g−1 for Na-ZrP and HEU–HTA-Na-ZrP, respectively. Thermodynamics, isotherms and kinetics suggested an endothermic, spontaneous, homogeneous and chemisorption process. Characterization verified the adsorption capacities of Th(IV), and the main possible Th(IV) adsorption mechanisms were associated with ion exchange and –OH, Zr–O coordination. Notably, the reusability study indicated that the samples treated with 0.1 mol⋅L−1 H3PO4 solution exhibited excellent reusability. Dynamic adsorption results indicated the structural stability of the composite pellets. 50% Th(IV) breakthrough time (τ (min)) increased with increasing mass and then decreased, and τ (min) decreased with increasing pH. Both Thomas and Yoon–Nelson models could better describe the Th(IV) dynamic adsorption behaviour. Moreover, HEU–HTA-Na-ZrP-P could separate Th(IV) from simulated and real nuclear wastewater. This work demonstrates that HEU–HTA-Na-ZrP can be applied as an efficient adsorbent for the removal of Th(IV) from Th-containing solutions.

Effective radioactive strontium removal using lithium titanate decorated Ti3C2Tx MXene/polyacrylonitrile beads

A lithium titanate-decorated Ti3C2Tx MXene (LTO-MX) composite was synthesized through etching and alkali processes, and subsequently immobilized using polyacrylonitrile (PAN) polymer via a phase inversion method. In the batch study, the strontium adsorption behavior followed the Redlich-Peterson isotherm and the pseudo-second-order kinetic models. The maximum adsorption capacity for strontium reached 24.05 mg/g. Furthermore, a continuous fixed-bed column study was performed using the LTO-MX PAN beads to remove strontium from aqueous solutions. The dynamic behavior of column adsorption was examined under various operating parameters such as initial strontium concentration, flow rate, and bed height. Dynamic modeling was employed to describe adsorption breakthrough properties based on these experimental data. Both the Thomas and Yoon-Nelson models accurately simulated the breakthrough curves. The proposed mechanisms for strontium adsorption included encapsulation, electrostatic attraction, cation exchange, and surface complexation. These results demonstrate the effectiveness of LTO-MX PAN beads as adsorbents for the continuous removal of strontium from radioactive wastewater.

Sorption-enhanced intensified CO2 hydrogenation via reverse water–gas shift reaction: Kinetics and modelling

Intensification of CO2 hydrogenation via the reverse water–gas shift (RWGS) reaction for CO production can be achieved through in situ removal of water when hydrophilic adsorbents are incorporated alongside the catalyst in the reaction bed. In this work, seeking to move a step closer to the industrial implementation of this innovative CO2 valorization process, a comprehensive reactor model, validated by experimental data obtained in a fixed-bed reactor, was developed to simulate the behavior of this sorption-enhanced (SE) RWGS process. Simulation and experimental data matched with good accuracy, demonstrating the striking benefits brought by the adsorbent addition, such as an almost doubling of the CO production rate at 300 °C. The kinetics of RWGS reaction over a Cu-based catalyst and H2O adsorption on a 13X zeolite adsorbent were studied both experimentally and theoretically and the kinetic models were integrated into the reactor model to assess the performance of SE-RWGS process. Fitting of the RWGS reaction rates by a Langmuir-Hinschelwood-Hougen-Watson-type heterogeneous kinetic model suggested that the rate-determining step of the reaction is the surface interaction between an adsorbed CO2 molecule and a H* species on catalytic sites of different nature. Meanwhile, the dynamic behavior of water adsorption was effectively simulated by a semi-empirical double-stretched exponential model combined with the Sips isotherm model. The results of this work could be applied to the design and scale-up of the SE-RWGS process, which offers considerable improvements over the thermodynamically constrained conventional process. The intensified approach represents a promising avenue for the effective conversion of carbon dioxide into CO, as well as into other value-added chemicals as part of a multi-stage CO2 reduction process.

Interfacial dynamic adsorption behaviour of the bovine alpha- Lactalbumin at the oil-water interface: Evaluating the role of glycyrrhizin

The contribution of glycyrrhizin (Gy) on the interfacial dynamic adsorption behaviour of the adsorbed layer formed by the bovine alpha-Lactalbumin (α-La) at the oil-water interface were investigated using the interfacial viscoelasticity and quartz crystal microbalance with dissipation (QCM-D) techniques. Compared to the individual α-La, Gy could decrease the interfacial tension, effectively enhancing their adsorption processing. The adsorption kinetic results revealed the diffusion rate of the α-La reduced at 0.5–2.0 mM Gy and its rate constant of rearrangement increased except for 2.0 mM. Also, Gy reduced the viscoelastic modulus including the elastic and viscous modulus of the adsorbed film formed by the α-La. Additionally, more adsorbed mass on the oil-water interface was observed in the α-La/Gy complex according to the QCM-D results, which can improve the stability at the oil-water interface. These results are expected to provide basic interfacial adsorption information for the film formed by multi-component.

Understanding the foam stability mechanisms of complex formed by soy protein isolate and different charged polysaccharides: Air/water interfacial behavior and rheological characteristics

This study evaluated the foaming properties, the dynamic adsorption behavior at the air/water (A/W) interface and the foam rheological characteristics of complexes formed by soy protein isolate (SPI) and different charged polysaccharides, including chitosan (CS), guar gum (GUG) and gellan gum (GEG). The results showed that the SPI/CS10 had the highest initial foam volume (26.67 mL), which were 3.89 %, 100.08 % and 70.19 % higher than that of single SPI, SPI/GUG and SPI/GEG complexes, respectively. Moreover, three charged polysaccharides could all significantly improve the foam stability of complexes. Among them, foams stabilized by SPI/GEG10 were the most stable that the foam volume slightly changed (approximately 1 mL) and no drainage occurred throughout the whole recording process. The interfacial behavior analysis showed that SPI/CS10 had higher diffusion (Kdiff) and rearrangement rate (KR) but lower penetration rate (KP) at the A/W interface compared with single SPI, while SPI/GUG10 and all SPI/GEG complexes showed higher KR and KP but lower Kdiff. In addition, SPI/CS10 was beneficial to concurrently enhance the elastic strength and solid-like behavior of foam system, while all SPI/GEG complexes could improve the elastic strength of foam system but was not conducive to the solid-like behavior.

Hydrophobic modification of walnut shell biomass-derived porous carbon for the adsorption of VOCs at high humidity

Volatile organic compounds (VOCs) often contain water vapor in their exhaust emissions, resulting in the deterioration of the adsorption capacity of activated carbon (AC). A hydrophobic walnut shell biomass-derived AC using polytetrafluoroethylene (PTFE) and polydimethylsiloxane-coated SiO2 (PDMS/SiO2) was developed to improve the selectivity of VOCs under high humidity conditions. These modified ACs were systematically characterized, and dynamic adsorption behaviors of VOCs such as toluene, acetone and their mixtures at the relative humidity (RH) between 0 and 90 % were conducted. The results showed that walnut shell biomass-derived AC has large specific surface area (1853 m2/g) and total pore volume (1.27 cm3/g), strong hydrophilicity (water contact angle of 6.3°), abundant oxygen-containing groups (OH, CO, CO) and aromatic rings. The coating of PDMS/SiO2-PTFE reduces the surface area and total pore volume of AC, but it creates a double-layer rough structure on the AC surface and introduces CF and SiOSi hydrophobic groups, which achieves a water contact angle of 152.8° for 25PSP/AC. The Yoon-Nelson model is suitable to describe the dynamic adsorption process of single- toluene or acetone under dry/humid condition but not suitable for their mixtures. At RH 90 %, PDMS/SiO2-PTFE modified AC significantly increases the adsorption capacity of toluene but is not obviously improved for acetone, which is due to the different polarity of toluene and acetone. PDMS/SiO2-PTFE films on AC have good thermal stability before 500 °C and the hydrophobicity does not change after multi-regeneration at 200 °C. Therefore, PDMS/SiO2-PTFE modified AC has shown great potential as adsorbent to remove the toluene from the humid condition.

Static and dynamic adsorption of arsenate from water by Fe3+ complexed with 3-aminopropyltriethoxysilane-modified carboxymethyl chitosan.

Fe3+ complexed with 3-aminopropyltriethoxysilane (APTES)-modified carboxymethyl chitosan (CMC) named Fe-ACMC was synthesized by a one-step method at room temperature and pressure. The surface morphology and chemical structure of Fe-ACMC were characterized by SEM-EDS, XRD, BET, FT-IR, XPS, and ζ-potential. In batch adsorption, the optimum pH for arsenate [As(V)] adsorption onto Fe-ACMC was 3-9 with removal efficiency > 99%. The adsorption of As(V) could reach equilibrium within 25min and the maximum adsorption capacity was 84.18mgg-1. The pseudo-second-order model fitted well the kinetic data (R2 = 0.995), while the Freundlich model well described the adsorption isotherm of As(V) on Fe-ACMC (R2 = 0.979). The co-existing anions (NO3-, CO32-, and SO42-) exhibited a slight impact on the As(V) adsorption efficiency, whereas PO43- inhibited As(V) adsorption on Fe-ACMC. The real applicability of Fe-ACMC was achieved to remove ca. 10.0mg L-1 of As(V) from natural waters to below 0.05mg L-1. The regeneration and reuse of Fe-ACMC for As(V) adsorption were achieved by adding 0.2mol L-1 HCl. The main adsorption mechanism of As(V) on Fe-ACMC was attributed to electrostatic attraction and inner-sphere complexation between -NH2···Fe3+ and As(V). In fixed-bed column adsorption, the Thomas model was the most suitable model to elucidate the dynamic adsorption behavior of As(V). The loading capacity of the Fe-ACMC packed column for As(V) was 47.04mgg-1 at pH 7 with an initial concentration of 60mg L-1, flow rate of 3mLmin-1, and bed height of 0.6cm.

Insights into simultaneous efficient removal of cationic and anionic dyes by nitrogen-rich seaweed carbon adsorbent

Textile dyes, including methylene blue (MB) and methyl orange (MO), pose a significant threat to water quality. This study delves into the competitive adsorption mechanisms pivotal for the concurrent removel of cationic MB and anionic MO dyes using nitrogen-rich seaweed-based carbon adsorbents. Synthesized through the pyrolysis and NaOH activation of Enteromorpha seaweed biomass, the preparation method is both uncomplicated and cost-effective, holding promising applications in industry. Characterization unveiled a commendable specific surface area of 911 m2/g, accompanied by abundant nitrogen- and oxygen-containing functional groups. Batch adsorption experiments showcased exceptional removal efficiencies surpassing 99.8% for both dyes. Molecular dynamics simulations offered valuable insights into the dynamic multi-stage adsorption behavior, while density functional theory calculations clarified the chemisorption-based interaction mechanism. Notably, MB displayed superior adsorption affinity compared to MO. An integrated adsorption mechanism was proposed, encompassing electrostatic attraction, migration, and enhanced chemisorptive binding of dye aggregates at active sites on the adsorbent surface. The innovative adsorption mechanism adopted by this carbon-based adsorbent prepared from nitrogen-rich seaweed can effectively remove cationic and anionic dyes, laying a solid foundation for future research on real water bodies with complex compositions.

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

The occurrence of benzene, toluene, ethylbenzene, and xylene (BTEX) in the environment has human health and ecological consequences; hence, it is essential to remediate the gas-phase industrial plume before its release. A laboratory-scale experimental apparatus was designed to investigate single-component gas-phase adsorption of BTEX compounds on commercially available granular activated carbon (CGAC) and laboratory-developed Mesquite-derived granular activated carbon (MDAC). The physical properties of CGAC and MDAC show that these adsorbents have a high N2 BET surface area, with CGAC exhibiting microporosity features. The single-component adsorption of BTEX was modeled by considering the transport of BTEX by axial dispersion, convective transport, and accumulation in the adsorbent bed at isothermal conditions. A linear driving force model was used to examine the mass transfer process. The experimental breakthrough curves showed good agreement with the modeled breakthrough curves. The modeling parameters demonstrated the dominance of intraparticle diffusion with a negligible external diffusion of BTEX onto CGAC and MDAC. The analysis of experimental data validated the modeled dynamic behavior of BTEX adsorption onto CGAC and MDAC. Overall, BTEX compounds followed Langmuir isotherms for both adsorbents, with intra-particle diffusion as a dominant gas phase adsorption mechanism.

Dynamic adsorption and desorption behaviors of rosin colloids onto and from cellulose nanofibers in aqueous media

Dynamic adsorption and desorption behaviors of rosin colloids onto and from cellulose nanofibers in aqueous media

Experimental Study on Enhanced Phosphorus Removal Using Zirconium Oxychloride Octahydrate-Modified Efficient Phosphorus Removal Composite

In addressing eutrophication and enhancing water quality, this study builds upon previous research involving the development of an Efficient Phosphorus Removal Composite (EPRC), a material created using modified industrial wastes (steel slag and fly ash) as adsorbent substrates, supplemented with a binder and porosity-forming agent. In this investigation, the EPRC was further enhanced through the addition of zirconium oxychloride octahydrate, resulting in the production of Zr-EPRC particles as reinforced phosphorus removal materials. Comparative experiments were conducted to assess different methods for preparing Zr-EPRC, the static adsorption performance, and dynamic adsorption behavior. The optimal preparation of Zr-EPRC was achieved by separately modifying the base materials, steel slag and fly ash. Loading with mass ratios of zirconium chloride octahydrate to fly ash and steel slag at 0.4 and 0.6, respectively, for a duration of 12 h at a pH of 10 yielded the best results. In static adsorption experiments conducted at temperatures of 15 °C, 25 °C, and 35 °C, Zr-EPRC exhibited saturated phosphorus adsorption capacities of 11.833 mg/g (variance = 0.993), 12.550 mg/g (variance = 0.993), and 13.462 mg/g (variance = 0.996), respectively. Zr-EPRC emerges as a cost-effective and readily available solution with promising stability for general wastewater treatment applications, contributing significantly to the mitigation of eutrophication and the improvement of water quality.