Adsorption最新文献

The composite adsorbent derived from titanate nanotubes (TNTs), layered double hydroxides (LDHs) and oyster shell (OS) were used to removal cationic and anionic dyes. Scanning electron microscopy confirmed the successful integration of TNTs, LDHs, and OS, displaying distinct rod-like and hexagonal structures, as well as a rough surface. Energy dispersive spectroscopy identified essential elements such as calcium, sodium, oxygen, titanium, and aluminum, critical for the composite’s functionality. X-ray diffraction revealed characteristic peaks corresponding to anatase-phase titanium dioxide, LDHs, and calcium carbonate, validating TLO’s structural integrity. Fourier-transform infrared spectroscopy detected functional groups vital for adsorption, including OH-, Ti-O, and Ca-O bonds. BET surface area analysis (BET) showed a significantly larger surface area of 82.11 m²/g for TLO compared to its individual components, enhancing its adsorption capacity. Zeta potential analysis demonstrated a variable surface charge across a range of pH values, enabling TLO to effectively adsorb both cationic and anionic pollutants. Methylene blue, acid red 1, and congo red, in pH 3 to 9 solutions, showed high capacities, with maximum values of 1111 mg/g for methylene blue, 357 mg/g for acid red 1, and 192 mg/g for congo red. These results highlight TLO’s strong electrostatic attraction and ion exchange for cationic dyes, and surface precipitation for anionic dyes, particularly in neutral to alkaline environments. TLO is regarded as an effective material for advanced wastewater treatment.

Investigation of NaI adsorption on Porous Silica Nanoparticles (PSN-blank) and functionalized PSN (PSN-NH₂) was conducted to study the possibility of PSN radiolabeling using adsorption techniques. This research aims to study the radiolabeling of ¹³¹I compounds with porous material nanoparticles using the adsorption method. The study began with the adsorption study of NaI (non-radioactive) to understand the initial adsorption behavior on two types of nanoparticles: PSN-Blank and PSN-NH₂. Adsorption parameters such as temperature, time, pH, initial concentration of adsorbate, and functional groups were studied to predict the most influential parameters in the radiolabeling process. The adsorption kinetics were evaluated to determine whether they tended to be pseudo-first or pseudo-second order. The NaI adsorption isotherms on PSN-Blank and PSN-NH₂ at different temperatures were also tested using the Langmuir and Freundlich models. The investigation results showed that the adsorption of NaI on PSN-Blank and PSN-NH₂ was spontaneous, endothermic, tended to obey pseudo-second-order adsorption kinetics, and the adsorption isotherm of the Langmuir model. The activation energy of NaI adsorption on PSN-NH₂ was higher than that on PSN-Blank. After the adsorption characteristics of NaI by PSN and PSN-NH₂ were comprehended, actual radiolabeling experiments using the ¹³¹INaI adsorption were carried out. The radiolabeling results showed, the presence of amine groups increases the adsorption rate of PSN and makes the PSN bond with the labeled compound more stable. The presence of amine groups increases the radiochemical yield and stability of ¹³¹I-labeled PSN compounds.

In this work, efficient black carbon nanoparticles were prepared rubber under O₂ and Ar atmosphere for the removal of methylene blue (MB). The nanomaterials obtained were characterized using SEM, N₂ adsorption isotherms, XRD, EDS, TGA, DLS, RAMAN, FTIR, UV-Vis and cytotoxic test. Batch experiments were carried out to study the impact of the MB contact on adsorbates varying the contact time an MB initial concentration. The optimal fit was by pseudo-second-order model of the experimental data of the adsorption kinetics in both adsorbents. The BCNPO presents a greater rate of adsorption of 30 mg/L of MB at 9 min can be due to the greater surface area with respect to the 7.5 mg/L of MB on BCNPA. The isotherms adsorption of MB in adsorbents was fit at Langmuir and Freundlich models. The data demonstrated that physisorption mechanisms predominantly dictated both the rate and interaction adsorbate-adsorbent of the adsorption process. The results showed that both physisorption mechanisms controlled the adsorption rate and capacity. All the samples showed selectivity toward MB. The maximum efficiency of adsorption of MB was found to be 130 and 28 mg/g in BCNPO and BCNPA, respectively. The adsorbed amounts of MB on the BCNPO are greater than those on BCNPA; this result can be due to a larger surface area, pore diameter and the presence of the OH groups on the surface of the BCNPA sample rather than interaction with cationic of MB. Additionally, the viability of cells exposed toward BCNPO and BCNPA showed low toxicity that were important result for potential water remediation applications. The adsorption of MB dye on BCNPA and BCNPO is a spontaneous and exothermic process.

Surface area and porosity are the main factors that affect hydrogen storage at room temperature. However, there are several external factors such as pressure of gas, reaction time and the amount of sample used during the process that might affect the performance of the hybrid nanocomposites towards hydrogen storage. In this study, central composite design (CCD) for response surface methodology (RSM) was used in determining the optimum conditions namely mass of sample (A), pressure of hydrogen gas (B) and reaction time (C) towards the hydrogen storage at room temperature. Rice husk derived graphene-like material (GRHC) was added into zeolitic imidazolate frameworks-8 (ZIF-8) to form a hybrid nanocomposite of ZIF-8/GRHC (ZGK) via in-situ synthesis. Due to synergistic effect, the surface area of ZGK (1065.51 m²/g) shows a great enhancement as 0.04 g GRHC was introduced as compared to pristine ZIF-8 (687.32 m²/g). On the other hand, the thermal stability of ZGK improved significantly as it can withstand up to 1000 ºC as compared to pristine GRHC and ZIF-8 respectively. Due to superior physicochemical properties of ZGK, it was chosen to undergo optimization of hydrogen storage at room temperature. From the confirmatory test which was run for three times, the optimum hydrogen storage at room temperature in ZGK was 1.95 wt.% when 0.50 g of ZGK was used; 15 bar of hydrogen gas was applied and the reaction time was 60 min as per suggested from the CCD.

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Most hydrogels for dye treatment only have the adsorption ability for anionic or cationic dyes, while a few zwitterionic hydrogels that can adsorb both anionic and cationic dyes need a complicated regeneration process when they are reused. To prepare reusable zwitterionic adsorbent hydrogels, in this paper, a zwitterionic composite hydrogel with Ag@g-C₃N₄ was prepared, which not only can adsorb both anionic and cationic dyes but also has photocatalytic degradation ability. The scanning electron microscopy images show that the optimum hydrogel has a large number of micro pores for dye adsorption. The adsorption capacity of the hydrogel achieves the highest in mixed dye concentration of 50 mg·L^-1 with pH value of 7–9. Benefiting from the synergistic effect of adsorption and photocatalytic degradation, the removal efficiency of methyl orange and methylene blue in mixed dyes was up to 93.86% and 91.80%, respectively. The photocatalytic activity trapping experiments showed that superoxide radicals as well as hydroxyl radicals played a major role in photocatalytic degradation. After 5 consecutive photocatalytic degradations, the removal ratio of the hydrogel for dyes was still above 80%, indicating good photocatalytic degradation and reusability properties. This research suggested the zwitterionic composite hydrogel has a promising prospect in removing dyes from wastewater treatment.

This work explores the sensing capabilities of Cr and Cu modified WS₂ nanosheets in detecting desflurane (C₃H₂F₆O) molecule to search for the most efficient sensing nanomaterials. Adsorption of C₃H₂F₆O molecule on the pristine and Cr/Cu modified WS₂ nanosheets was studied using the density functional theory calculations. Desflurane was adsorbed from both oxygen and Fluorine active sites after the adsorption structures were fully optimized. The relaxed configurations were utilized for calculating geometrical and electronic properties such as adsorption energies, projected density of states and band structures. The negative adsorption energies indicated the stable adsorption of desflurane on the Cr and Cu modified WS₂ nanosheets. The results also indicated that desflurane adsorption did not change the electronic properties of Cr and Cu modified WS₂ considerably, except for some changes in the band gap interval. Based on spin-polarized calculations, both Cr and Cu modified WS₂ monolayers magnetic and semiconducting properties. These findings suggested that Cr and Cu modified WS₂ nanostructures are brilliant candidates for sensing C₃H₂F₆O molecules.

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, N_2, 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.

The efficient elimination of synthetic dyes from industrial wastewaters continues to be a significant environmental issue. This paper describes one-pot synthesis of zinc titanate nanocomposites exhibiting dual adsorption and photocatalytic properties, achieved using precipitation/calcination and solvothermal techniques from a common precursor solution. Methylene blue (MB), a frequently utilized cationic dye, was chosen as the model contaminant. The zinc titanate composites exhibited significant adsorption capabilities; consistently attaining > 4 mg of MB adsorbed per gram of material for all Zn/Ti ratios within the initial 30 min in the absence of UV light exposure. Composites having a Zn/Ti ratio of 0.5 exhibited superior performance, with Z-0.5c attaining the maximum photocatalytic degradation under UV illumination. Phase analysis indicated that calcination resulted in increased crystallinity, which was associated with improved photocatalytic activity, while solvothermally generated samples preserved nanoscale morphologies that facilitated adsorption. The results underscore the efficacy ofzinc titanate nanocomposites as dual-function materials for wastewater treatment, facilitating fast adsorption and prolonged photocatalytic degradation to enhance dye elimination. This study offers significant insights into the optimization of Zn/Ti ratios and synthesis techniques for improved environmental applications.

In the present study, the capability of Al, Si, P doped and novel TiAl₃ decorated MoS₂ nanosheet for sensing and adsorption of the acrolein molecule has been scrutinized through the periodic density functional theory. The changes in the energy gap after trapping acrolein molecule can be regarded as a positive factor for analyzing the electrical response of the sensor material. The adsorption energies on the doped MoS₂ nanosheets are higher than those on the pure nanosheets, indicating the principal influence of doping on the adsorption efficiency of substrate. Among the Al, Si and P doped MoS₂ systems, the highest value of adsorption energy (-0.92 eV) was observed for the Si-doped nanosheet. Also, the TiAl₃ decorated MoS₂ nanosheet exhibits a very strong adsorption effect on the acrolein molecule with considerable energy of -3.76 eV. The charge density differences for the interaction of acrolein with doped MoS₂ substrates were analyzed to search for the changes occurred at the adsorption region. Based on the obtained results, we can propose the TiAl₃ decorated MoS₂ substrates as potential sensors of acrolein molecules.

This study investigated the utilization of a unique oil shale as a sorbent for the removal of 2,4-dichlorophenol (2,4-DCP) from aqueous solutions. The influence of various process parameters, including the contact time, sorbent/liquid ratio, pH, and temperature, on the sorption process was evaluated. The results indicated the near-complete sorption of 2,4-DCP within 24 h. Favorable sorption was observed either at a sorbent/liquid ratio of 1:10, at elevated temperatures (40 °C), or at lower pH values (pH = 5) within the examined range. The maximum adsorption capacity at 40 °C has the potential to reach up to 20.0 µmol/g. Langmuir, Freundlich, and Sips isotherms were applied to the experimental data, but the Sips isotherm provided a superior fit, suggesting a heterogeneous sorption. Kinetic studies revealed a two-stage process: intraparticle diffusion dominated the initial stage, whereas other rate-limiting mechanisms may have contributed to the second stage. The first- and second-order kinetic models suggested a combined mechanism. According to the thermodynaic study, the adsorption process was spontaneous and exothermic, as indicated by the negative Gibbs free energy change and enthalpy change, which suggest that physisorption predominated. These findings demonstrate the potential of the investigated oil shale as an unconventional and cost-effective sorbent, potentially serving as a substitute for activated carbon in 2,4-DCP removal.

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