Adsorption最新文献

In this work, we investigate the structural parameters that affect water adsorption on amorphous carbon nitride thin films synthesized by pulsed laser deposition. The study includes the case of ablation of graphite targets within molecular nitrogen and within a stream of nitrogen plasma afterglow. The results obtained showed that, the effect of Csp²-Csp² bonds concentration on the adsorption of water molecules depends strongly on the ratio and distortion of the hexagonal rings. Furthermore, analysis of the spectral data showed that, the relationship between the hydrogen bonding strength of water molecules with the film surface and the concentration of Csp²-Csp² bonds takes a specific mathematical formula in the case of structures composed mainly of hexagonal rings.

Capturing CF₄ is crucial for mitigating its substantial greenhouse effect and environmental impact in the microelectronics industry. Here we employed a hybrid approach combining grand canonical ensemble Monte Carlo molecular simulations and neural network models to screen over 100 amorphous materials for N₂/CF₄ gas adsorption storage and separation. Materials with higher adsorption capacities exhibited densities around 0.7 to 1.0 g/cm³ and pore sizes within the range of 1.4–1.6 Å. At 298 K and 1000 kPa, HCP-Colina-id0016 and aCarbon-Bhatia-id001 demonstrated the highest CF₄ adsorption, reaching 5.65 and 5.34 mmol/g, respectively. For the separation of N₂/CF₄ mixtures, considering the comprehensive CF₄ adsorption selectivity and capacity, we recommend HCP-Colina-id0016 at high pressure conditions (4500 kPa) and aCarbon-Bhatia-id001 at medium to low pressures (below 500 kPa). The separation of mixtures is more favorable at low CF₄ concentrations, becoming more challenging as CF₄ concentration increases. Additionally, the Ideal Adsorbed Solution Theory (IAST) accurately predicted the separation of the N₂/CF₄ system on amorphous materials. We found that the genetic algorithm-optimized neural network (GA-BP) outperformed the standalone backpropagation neural network (BP) in accurately predicting the relationship between material structural properties and CF₄ adsorption, showing its potential for widespread application in large-scale material screening.

Tetracyclines (TCs) constitute a group of antibiotics that are commonly used to treat bacterial diseases, in veterinary medicine and as an additive in animal feed. This broad application has led to their accumulation in food products and the environment because sewage treatment plants cannot completely remove them. Therefore, the aim of this study was to synthesize graphene oxide (GO) and evaluate its TC adsorption properties in aqueous media. The effects of pH (between 2.5 and 11) and Ca²⁺ concentration (between 0 and 1 M) were thoroughly investigated. Structural, textural, and electrokinetic properties of the prepared GO were determined by N₂ adsorption/desorption, XRD, TEM, UV–vis, FTIR, XPS, thermogravimetry and electrophoretic mobility measurements. TC adsorption on GO is an interplay between the two main roles played by Ca²⁺: competitor or bridging cation. At low pH, there is cation exchange, and Ca²⁺ behaves as a competitor of the positively charged TC species, decreasing adsorption as calcium concentration increases. At high, the formation of Ca bridges between the surface and TC (GO-Ca²⁺-TC) is favored, increasing the adsorption of the antibiotic by increasing calcium concentration. Different combinations of Ca²⁺ and pH effects are important to improve the use of GO either as a pH-dependent and reversible TC adsorbent for decontamination or as pH-independent adsorbent for TC quantification with electrochemical sensors.

This study investigates the sensitivity and selectivity of gas adsorption (SF₆, SO₂F₂, SOF₂, SO₂, and HF) on SiGe surfaces and Ca atom-decorated SiGe surfaces using Density Functional Theory (DFT). The optimized structures, bond lengths, and angles of the gas molecules are analyzed, providing valuable insights into their geometric features and bonding configurations. For every gas on both surfaces, important variables such as adsorption energy, and charge transfer are examined. In particular, there is a significant increase in charge transfer and adsorption energy when SF₆ interacts with Ca$2D-SiGe as opposed to the SiGe surface. To emphasize changes in band gap and electronic structure, the study explores electronic properties such as density of states (DOS) and projected density of states (PDOS) spectra before and after gas adsorption. Electron density differences (EDD) analysis is used to clarify the type of interactions, including accumulation and depletion of charge. The results reveal that all gases except HF/ Ca$2D-SiGe showed chemical adsorption. The study also takes into account recovery time, an important metric for sensor materials, which is calculated for the breakdown gases of SF₆ on both surfaces at different temperatures and shows potential uses for gas detection. Future research should focus on a broader range of gas molecules and their interactions with SiGe and Ca-decorated SiGe surfaces. Ultimately, the integration of SiGe-based sensor devices in real-world applications such as environmental monitoring, industrial safety, and medical diagnostics can be explored to understand the broader potential of these materials in the field of gas detection.