Adsorption最新文献

The uncontrolled release of waste diclofenac with low biodegradability is considered to be a potential threat for the environment and creatures. To find effective solution for this issue, this study reports the adsorption performance of diclofenac sodium salt (DCF) by using activated carbon (EHAC) obtained from einkorn (Triticum monococcum L.) husk in aqueous solution under various circumstances. It was found that DCF adsorption on EHAC was highly solution pH dependent, and DCF adsorption by EHAC decreased with increasing adsorption temperature. Equilibrium data showed that fitted isotherm model with the experiment results of DCF adsorption on EHAC followed the order of Langmuir > Temkin > Freundlich > Dubinin-Radushkevich. Adsorption capacity of EHAC for DCF adsorption in aqueous solution was calculated to be 147.06 mg/g at 25 °C. The adsorption kinetic of DCF adsorption on EHAC was determined to obey the pseudo-second-order kinetic model. By utilizing FTIR and pH data obtained from DCF adsorption on EHAC, DCF adsorption mechanisms with some interactions such as π-π stacking, electrostatic interactions, and hydrogen bonding were suggested at diverse pH values. Additionally, intraparticle diffusion model was applied to kinetic results to further recognize the kinetic mechanism of DCF adsorption on EHAC. Furthermore, thermodynamic parameters for DCF adsorption on EHAC were calculated and evaluated, in which DCF adsorption process by EHAC was determined to be exothermic, spontaneous, and feasible.

Analysis of physicochemical properties and water treatment is vital for the environment and societal living standards. In this study, polyaniline (PANI)/enset fiber (EF), reduced graphene oxide/EF, and PANI/rGO/EF composites as adsorbent materials were prepared via facile in-situ chemical oxidative polymerization techniques. The as-synthesized materials were characterized using XRD, FTIR, UV-VIS, TGA, and SEM spectroscopy. Physical characterization revealed the deposition of PANI and rGO on the surface of EF, confirmed by the cloudy and wrinkled fibrous morphology observed in the SEM images. After physical characterization, the adsorption performance of the proposed materials was tested using the batch method. The results showed a maximum adsorption capacity (q_max) of Cu²⁺ and Pb²⁺ ions by PANI/rGO-coated EF was 10.11 mg/g and 13.4 mg/g, respectively, which is higher than that of pristine EF, PANI/EF, and rGO/EF. When all parameters were optimized, the adsorptive removal efficiency of PANI/rGO/EF composite material towards Pb²⁺ and Cu²⁺ ions was 99% and 97.77%, respectively. The Freundlich isotherm data for Cu²⁺ and Pb²⁺ showed a good fit with the experimental data (R² = 0.99 and 0.98), and Langmuir isotherm data for Cu²⁺ and Pb²⁺ (RL = 0.18 and 0.19), respectively. The pseudo-second-order kinetic isotherm was a better fit for physisorption, with R² = 0.99 for Cu2 + and R² = 1 for Pb²⁺. Therefore, the synthesized novel material PANI/rGO/EF shows remarkable adsorption performance compared to EF, PANI/EF, and rGO/EF, due to the doping-induced abundant active sites of the composite material, making it a promising candidate for wastewater treatment techniques.

Increasing demand for fossil fuels in worldwide leads to environmental issues. Fossil fuel containing nitrogen compounds is deactivating the industrial catalysts. There are several techniques for nitrogen removal such as hydrodenitrogenation, oxidative denitrogenation, and adsorptive denitrogenation, due to the restriction of the common method; Researchers have suggested metal–organic frameworks (MOFs) and MOF nanocomposite materials for adsorptive denitrogenation (ADN) and oxidative denitrogenation (ODN) of fuels in recent years. This review paper aims to investigate the adsorptive and oxidative denitrogenation of liquid fuels with MOFs-based catalysts. All catalysts including pristine MOFs, defected MOFs, active component-loaded MOFs, and MOF-derived carbonaceous materials are studied. The detailed mechanisms of different MOFs are investigated to further improvements and modifications to synthesis well catalysts for nitrogen compound removal from liquid fuels.

A model of desorption from the surface of rotating disk into the solution of surface active substance is developed for Frumkin isotherm. The time needed to approach the first equilibrium within 1% of error is investigated. For desorption this means to acquire the highest surface coverage, and for adsorption the lowest coverage that is in the equilibrium with the bulk of solution. If the equilibrium isotherm is S shaped, the near equilibrium isotherms are characterised by big changes of coverage that are caused by small increments of bulk concentrations. These changes require very long near equilibrating times because they are driven by small fluxes of dissolved surfactant. These times are the second component of the hysteresis.

A simple manual flow injection method was used to formulate chitosan-lignin composite beads in a ratio of 1:1. The beads were then characterized using FT-IR (Fourier Transform Infrared Spectroscopy), SEM (Scanning Electron Microscopy), TGA (Thermogravimetric Analysis), and XRD (X-ray Diffraction). The FT-IR results indicate the chemical composition, revealing the presence of C-O, NH, C-H, and OH on chitosan, as well as OH, C-O-C, C = C, -O-CH3, and C-H, showing the presence and dispersion of lignin within chitosan molecules. SEM was useful for looking at the surface shape and showed structural differences between pure chitosan (which had a smooth surface with few holes) and composite beads (which had sharp edges and a rough, wrinkled shape). The TGA sheds light on the thermal stability and degradation properties of the beads. The thermograms show a similar pattern; however, the degradation temperature improved with the addition of lignin. An XRD investigation revealed the crystalline nature of the beads. Chitosan beads showed a sharp peak at 2θ = 21.8°, whereas in composites, the first peak was observed at 2θ = 9.9° second at 2θ = 20.130° and the third at 2θ = 28°. These findings allowed for the possibility that chitosan/lignin composite beads may be a good adsorbent for use in wastewater treatment systems.

The bone regeneration process is complex and challenging and requires the application of biomaterials to promote adequate tissue growth and repair. Biomaterials traditionally used are produced with biocompatible and bioinert metal alloys, not presenting any response in the recipient tissue, whether negative, such as inflammation and infections, or positive, such as rapid and effective healing of the injured tissue. Using biomaterials with an active compound adsorbed in their structure allows a direct interaction between the material and the injured tissue, and consequent modulation of biological responses to promote bone formation. Such biomaterials can facilitate the adhesion of osteoprogenitor cells and other important biological factors for bone tissue regeneration and remodeling. This review explores the importance of considering adsorption during biomaterials production and understanding the bone regeneration process. In addition, focus is given to biomaterials produced from biopolymers based on cellulose and hydroxyapatite, as well as mechanisms of bone regeneration. Challenges remain for optimizing these processes, and the adsorption properties of different materials must be carefully investigated to guarantee adequate interaction with bone tissues and cells. Furthermore, the development of strategies to control the release of adsorbed components is crucial to obtain efficient and targeted bone tissue regeneration.

Dyes are one of the most threatening toxins released from industry. Methylene blue (MB) is one of the extremely common dyes in the textile industry. Being complicated in structure and non-biodegradable in nature, removing MB from the aqueous environment is a great challenge. Elimination of dye is usually performed in two ways, degradation, and adsorption. Iron-based nanoparticles, being biocompatible and non-expensive, became a hot field of research in the context of the elimination of toxic dyes. In our review article, we consolidated the data about the synthesis, nature, state, and applications of iron-based nanoparticles to remove MB dye from aqueous solutions specifically via adsorption and degradation. We also reviewed the effect of doping on nanoparticles and their effects on dye removal capacity. Physiological factors such as pH, and temperature play an important role in iron-based nanoparticle synthesis as well as dye degradation and adsorption. A comparative account between adsorption and degradation was tried to depict the elimination of dye in various aspects including efficiency and mechanism.

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Reduced silver mordenite has been considered as a sorbent for the capture of organic iodides, especially methyl iodide, from off-gases produced by aqueous used nuclear fuel reprocessing operations. The adsorption capacity of this material has been unpredictable especially when NO_x and water are present. Previous work has found that a catalytic decomposition reaction is occurring on the surface but few determinations have been made of the kinetics of this reaction. The work presented tested the adsorption behavior and apparent catalytic reaction rate in humid conditions and compared those to dry conditions testing. Both experiments observed a first order reaction with rate constants of 0.0847 L/g sorbent/s and 0.1202 L/g sorbent/s respectively. Such a reduction in apparent rate constant is possibly due to either water obstructing methyl iodide adsorption or product desorption limitation. Changes in the adsorption profile were also apparent between these two, with the humid conditions experiment reaching saturation sooner than the dry conditions experiment. Additionally, an experiment into the effects of sorbent storage in a controlled laboratory environment was performed. The performance of the sorbent materials that were stored with silver in the zerovalent state was slightly inferior to those materials that were stored in ionic form (Ag⁺) and reduced to zerovalent silver immediately prior to subjecting them to sorption test. The materials stored with silver in the ionic form (and reduced just prior to application) behaved essentially similarly to the freshly synthesized (and reduced) sorbents in the sorption tests. This suggests that zerovalent silver experiences some oxidation resulting in deactivation of some sites.

Eragrostis plana Nees is an invasive species in Brazilian territory, known for its high levels of lignin, cellulose, and hemicellulose, making it a valuable raw material for activated carbon (AC) production. In this study, AC derived from Eragrostis plana Nees leaves was investigated as an adsorbent for silver nanoparticles (AgNPs). Kinetics, equilibrium, and thermodynamic assays were conducted to assess AgNPs adsorption onto AC. The AC exhibited a substantial surface area of 1030 m² g⁻¹ and demonstrated significant adsorption capacity for AgNPs. Both the pseudo-second-order and Langmuir models were found to best describe the kinetics and equilibrium of adsorption, with the highest adsorption capacity observed at 55 °C, reaching 140.19 mg g⁻¹ according to the Langmuir model. Thermodynamic analysis revealed an enthalpy change (∆H°) of 60.75 kJ mol⁻¹ and an entropy change (∆S°) of 0.2711 kJ mol⁻¹ K⁻¹, indicating that the adsorption process is spontaneous and endothermic. Additionally, the AgNPs/AC composite exhibited excellent catalytic activity in the 4-nitrophenol reduction, achieving a conversion rate of 97% within 10 min.