Adsorption最新文献

In this project, we have studied the possibility of using the C2N Monolayer (ML) for sensing and adsorption of several chlorofluorocarbon (CFC) derivatives from the gaseous environment. The density functional theory (DFT) approach was applied to optimize the geometrical structures of the isolated C2N ML and its complexes with of CH₃F, CH₂F₂, CHF₃, CH₃Cl, CH₂Cl₂, CHCl₃, and CF₂Cl₂ air pollutants gases. The results of the thermodynamics of adsorption indicated that C2N ML could adsorb all of the considered CFCs except CF₂Cl₂. Also, the recovery time calculations showed that in all cases (from CHF₃ with the recovery time of 3.45(10^− 4) s to CF₂Cl₂ with the recovery time of 9.47(10^− 12) s) the C2N ML is a good recoverable sorbent. The results of the conductivity calculations indicate that the presence of CH₃F, and CH₃Cl increase the σ value for the isolated C2N ML from 1.94(10^− 29) S m^− 1 to 3.16(10^− 29) S m^− 1, and 3.07(10^− 29) S m^− 1, respectively. Thus, C2N ML is able to sence the presence of the mentioned CFCs.

In this work, we searched for the exclusive electronic and adsorption properties of Ag₄ cluster modified BSe based nanomaterials for the purpose of sensing glycine, hystidine and phenylalanine amino acids. Adsorption distances, band structures, difference in electron densities and interaction energies were calculated to understand the impact of amino acids adsorptions on the chemical reactivity of Ag cluster modified BSe nanostructures. Diverse configurations were inspected for the adsorption of amino acids to survey the effective bio interface through the interaction with diverse sites existing on the organic amino acid molecules. The interaction of all amino acids via O site was found to be critical for energetically favorable adsorption modes. The PDOS analysis also revealed the large interactions of the amino acids with the Ag cluster modified BSe nanosheets. Our theoretical DFT results suggested that Ag₄ cluster modified BSe nanostructures held great potential for practical applications in biomolecular sensing of amino acids.

Streamlined relationships are derived to predict the equilibrium composition in batch adsorption when the isotherm is described by the steric mass action (SMA) model, which is used extensively to represent macromolecule adsorption on ion exchange resins. In the general case with N components, the approach reduces the mathematical problem from a system of 2N equations to a single non-linear algebraic equation whose numerical solution is easily found. A graphical approach is also presented where isotherm lines describing mixture equilibrium values of the adsorbed concentrations of each component are plotted against the equilibrium solution concentration of a common reference species. In this case, the actual equilibrium composition is obtained at the intercept of the reference component equilibrium curve with the straight line representing the material balance for the reference species. Analytical expressions are provided for two and three-component mixtures. The graphical approach provides insight on the effects of the ratio of adsorbent and solution volumes on the equilibrium composition.

This article summarizes opening address in 9th Characterization of Porous Materials (CPM9). The role and historical sketch of main adsorption-based conferences such as Fundamentals of Adsorption (FOA), Characterization of Porous Solids (COPS), Pacific Basin Conference on Adsorption Science and Technology (PBAST), and Characterization of Porous Materials (CPM) are given. The unique role of CPM in adsorption-based characterization of porous materials is introduced in the above conferences. The concerted stimulation between innovated well-defined nanoporous materials and modernized adsorption studies supported by new theoretical and experimental approaches have given rise to quite active research activities mentioned above. The brief research activities of author’s group, which have aimed to bridge experimental and theoretical studies, are described; they have introduced in-situ X-ray diffraction, in-situ small angle X-ray scattering, high resolution adsorption measurement even from ultrahigh vacuum range, wide-temperature range in-situ IR spectroscopy for elucidation of the intermolecular structure of molecules adsorbed in nanopores. Also, future scope of the research on characterization of porous solids is proposed.

In this study, gold tailings were modified as a carrier and loaded with iron oxides. The composites with different Fe₂O₃ doping were prepared by adjusting the mass ratio of Fe₂O₃/modified slag (Fe₂O₃/MS) to obtain porous materials with larger specific surface area and more adsorption sites. The adsorption of Levofloxacin hydrochloride (LEV) from aqueous solutions over Fe₂O₃/MS samples was investigated. The process of adsorption was studied in terms of a number of variables, such as adsorbent dosage, LEV concentration, solution pH. The results showed that the optimal mass ratio of Fe₂O₃ to MS was 3:10. The ionic strength and coexisting ions had little influence on the adsorption effect of the composite material, so the material had a strong anti-interference ability. However, the pH of the initial solution and the ion phosphate had a significant effect on the adsorption effect, indicating that electrostatic and coordination interaction were the main adsorption mechanisms. The adsorption process of Fe₂O₃/MS to LEV can be better described by quasi secondary rate equation with a faster adsorption rate (K₂ = 4.43 × 10⁻³g/(mg·min)) and the maxmium adsorption capacity (Q_e= 57.65 mg/g). In a wide temperature range (288–308 K), the adsorption behavior of LEV can be well described by the Langmuir isothermal model. Moreover, the ecyclability and stability of the material was explored. This study provides a new idea for the recycling of gold tailings. While solving the problem of water pollution, it realizes the high value reuse of solid waste resources and achieves the purpose of using waste to curb pollution.

Cadmium is a threat to human health and the environment. Therefore, there is a need for efficient and sustainable adsorbents to remediate cadmium-contaminated water. This study explores the effectiveness of Rhassoul clay/alginate composite beads in adsorbing cadmium from aqueous solutions, a simple, efficient, and cost-effective water treatment method. Various physicochemical factors influencing the adsorption capacity of the Rhassoul/alginate hybrid composite beads were examined, including adsorbent dosage (0.5–4.0 g/L suspension), contact time (30–360 min), pH (2–7), initial Cd²⁺ concentration (20–200 mg/L), and temperature (25–40 °C). The results revealed an adsorption capacity of 20 mg/g for non-modified Rhassoul clay, while the Rhassoul/alginate composite beads exhibited a significantly higher maximum adsorption capacity of 105 mg/g. Thermodynamic parameters (∆G°, ∆H°, and ∆S°) indicated the process was spontaneous and endothermic.

Graphical abstract

Paraben contamination in aquatic systems, primarily from personal care products, pharmaceuticals and industrial effluents, is an increasing environmental concern due to their widespread use as preservatives. The removal of parabens through conventional wastewater treatment processes is challenging and requires the development of innovative water treatment methods. In this study, graphene oxide nanoflakes were produced by Improved Hummers’ method and their adsorption characteristics were investigated for simultaneous removal of five parabens. Fourier transform infrared spectroscopy, Raman Spectroscopy, X-Ray Powder Diffraction, Scanning Electron Microscope and Transmission Electron Microscope were used and the nanoflakes were successfully characterized. A chromatographic method was developed for the simultaneous quantification of parabens. Process optimization for overall removal efficiency of parabens was achieved using Response Surface Methodology by a multiple response function. Nonlinear regression was used to fit the equilibrium data and the Freundlich model described the adsorption isotherm data accurately with R² values between 0.9807 and 0.9957. Factors such as mass of adsorbent, pH of solution and their interaction have the most significant impact on the adsorption process, while contact time shows low significance on the response. The adsorption behaviors of parabens were closely correlated with their hydrophobicity. Along with hydrophobic interactions, other mechanisms such as π–π stacking, hydrogen bonding and electrostatic forces, likely played significant role in the strong adsorption of parabens onto the GO surface. The reusability experiment showed that graphene oxide nanoflakes had a high potential present as a reusable adsorbent for the removal of parabens.

The increasing presence of pesticide contaminants in water bodies poses significant environmental and health challenges. This study introduces a novel enzyme-based photocatalytic technology composed of reduced graphene oxide (rGO), zinc oxide (ZnO), and chitosan (CS) designed to enhance the degradation efficiency of diazinon pesticides in polluted water. The nanozymes were characterized by XRD, SEM-EDX, and FTIR to ensure homogeneous structure and distribution of the materials, and the adsorbed pesticide content was measured using a UV-Vis spectrophotometer. Adsorption studies showed that the diazinon removal efficiency increased with higher pH, longer contact time, and initial concentration, reaching maximum adsorption efficiency at neutral pH. Isotherm analysis showed that diazinon adsorption on rGO/ZnO/CS nanozymes followed the Freundlich model, exhibiting heterogeneous adsorption characteristics with moderate adsorption capacity. These findings highlight the potential of rGO/ZnO/CS nanozymes as effective adsorbents for removing diazinon pesticides from contaminated water, offering promising applications in environmental remediation.

In the modern era, there is a pressing need to develop potential gas adsorbents to reduce the toxic gases produced by modern technology in the environment. In this project, we have investigated 2D graphene and double-doped (B, N) nanosheets for adsorption of N₂O₄ gas. We used density functional theory calculations to examine how N₂O₄ gas interacts with pure graphene, doubly boron, nitrogen, and boron-nitrogen-doped graphene sheets. We study the geometrical structure changes, cohesive energy, electronic property, and optical property to assess the stability of the sheets and complex structures, as well as their adsorption ability. Upon analyzing the adsorption energy, we observe an increase in adsorption energies for all the doped nanosheets undergoing N₂O₄ gas adsorption. The band structure analysis reveals a change in the band gap due to doping and gas adsorption, suggesting an interaction between the gas and the nanosheets. The optical properties analysis primarily reveals the highest values in the X-ray region; however, the analysis of the change in intensity peaks and shifting in the UV region for all structures confirms the interaction between the N₂O₄ gas and the adsorbent.

Mass transport in nanoporous materials is a key property that allows to improve the performance of many gas separation processes and design more efficient heterogeneous catalytic reactors. In many instances a combination of surface resistance and internal diffusion are present. The combined model for surface barrier and diffusion in a ZLC system is discussed in detail and the analytical solutions valid for the traditional and the partial loading experiments have been derived for the spherical and slab geometries. The model reduces to the limiting forms of pure diffusion when (frac{k{R}_{p}}{D}>100), and pure surface barrier when (frac{k{R}_{p}}{D}<1). This study has shown that most literature studies have analysed ZLC responses incorrectly based on an effective combined dimensionless parameter. Two methods are described to obtain the parameters from the long-time asymptotic behaviour of the response curves. Both approaches have been demonstrated on curves generated from the full model solution and experimental data on an etched sample of Y zeolite. Both the analysis of the model and of the experimental results confirm that to characterize combined surface barriers and diffusion one should perform at least experiments at two different flowrates where the system is kinetically controlled, and crucially a partial loading experiment with a time to the switch which should be at least an order of magnitude smaller than the smallest of the diffusion and surface barrier times.