State‐of‐the‐art Fenton‐like reactions are crucial in advanced oxidation processes (AOPs) for water purification. This review explores the latest advancements in heterogeneous metal‐based catalysts within AOPs, covering nanoparticles (NPs), single‐atom catalysts (SACs), and ultra‐small atom clusters. A distinct connection between the physical properties of these catalysts, such as size, degree of unsaturation, electronic structure, and oxidation state, and their impacts on catalytic behavior and efficacy in Fenton‐like reactions. In‐depth comparative analysis of metal NPs and SACs is conducted focusing on how particle size variations and metal‐support interactions affect oxidation species and pathways. The review highlights the cutting‐edge characterization techniques and theoretical calculations, indispensable for deciphering the complex electronic and structural characteristics of active sites in downsized metal particles. Additionally, the review underscores innovative strategies for immobilizing these catalysts onto membrane surfaces, offering a solution to the inherent challenges of powdered catalysts. Recent advances in pilot‐scale or engineering applications of Fenton‐like‐based devices are also summarized for the first time. The paper concludes by charting new research directions, emphasizing advanced catalyst design, precise identification of reactive oxygen species, and in‐depth mechanistic studies. These efforts aim to enhance the application potential of nanotechnology‐based AOPs in real‐world wastewater treatment.
The interaction between light and molecules under quantum electrodynamics (QED) has long been less emphasized in physical chemistry, as semiclassical theories have dominated due to their relative simplicity. Recent experimental advances in polariton chemistry highlight the need for a theoretical framework that transcends traditional cavity QED and molecular QED models. Macroscopic QED is presented as a unified framework that seamlessly incorporates infinite photonic modes and dielectric environments, enabling applications to systems involving plasmon polaritons and cavity photons. This Perspective demonstrates the applicability of macroscopic QED to chemical phenomena through breakthroughs in molecular fluorescence, resonance energy transfer, and electron transfer. The macroscopic QED framework not only resolves the limitations of classical theories in physical chemistry but also achieves parameter-free predictions of experimental results, bridging quantum optics and material science. By addressing theoretical bottlenecks and unveiling new mechanisms, macroscopic QED establishes itself as an indispensable tool for studying QED effects on chemical systems.
Agnieszka Seremak, Izar Capel Berdiell, B. Arstad
et al.
The flexibility of the H-ZSM-5 zeolite upon adsorption of selected coke precursors was investigated using both theoretical and experimental approaches. Four structural models with varying active site locations were analyzed through density functional theory (DFT) simulations to determine their responses to different types and quantities of aromatic molecules. Complementary experimental analysis was performed, allowing for a direct comparison with the theoretical findings, using thermogravimetric analysis (TGA), nitrogen adsorption (N2 adsorption), solid-state NMR, and X-ray diffraction (XRD). By employing proposed flexibility descriptors, significant structural changes in the MFI-type zeolite framework were identified, particularly in the unit cell parameters and the morphology of the straight channels. These changes were driven by electrostatic repulsion between adsorbates and by electrostatic attraction between adsorbates and the zeolite framework. The observed structural changes depended on both the active site location and the size and number of coke precursors. Consistent trends in structural flexibility were observed in both experimental and theoretical studies, primarily driven by variations in organic species loading. Our findings show the critical importance of active site location in influencing the magnitude of framework flexibility, which, in turn, affects the stabilization and accommodation of different coke precursors within the zeolite structure.
Ahmed Ashour M., Essam Doaa, Kabatas Mohamed A. Basyooni-M.
et al.
This study reports the synthesis of a nanohybrid material composed of poly(2-methylaniline) (P(2MA)) and iron oxide (Fe2O3) as electrodes for supercapacitors using a simple and cost-effective method. Various characterization techniques were employed to analyze the samples. The results revealed that the Fe2O3/P(2MA) nanohybrid exhibits nanofiber structures, while pure P(2MA) displays a porous hollow sphere morphology. Furthermore, the analysis confirmed the effective dispersion of Fe2O3 nanoparticles within the polymer matrix. The electrochemical properties of the Fe2O3/P(2MA) nanohybrid were found to surpass those of pure P(2MA) in both NaCl and HCl electrolytes. Notably, the nanohybrid demonstrated longer discharge times and higher oxidation/reduction currents in HCl than NaCl. The gravimetric and areal capacitances were measured at 998.4 F g−1 and 1497.6 mF cm−2 in 0.5 M HCl at a current density of 0.6 A g−1. Furthermore, the nanohybrid retained 99.9% of its initial specific capacitance after 2,000 cycles. These findings underscore the significant potential of the Fe2O3/P(2MA) nanohybrid as a high-performance supercapacitor electrode for energy storage applications.
Muhammad Sultan Irshad, Naila Arshad, Ghazala Maqsood
et al.
The global water and energy crisis seems to be mitigated with promising prospects of emerging interdisciplinary hybrid solar-driven evaporator technology (IHSE). However, the lack of numeric standards for comparison between enormously reported systems and the synergistic effects of interdisciplinary hybridization remains a significant challenge. To entice researchers from various domains to collaborate on the design of a system for realistic, large-scale applications, this study provides a comprehensive overview of the interdisciplinary approaches to IHSE from the domains of physics, chemistry, materials science, and engineering, along with their guiding principles and underlying challenges. First, an in-depth analysis of IHSE with the basic scientific foundations and current advancements in recent years is discussed. Then, the physical principles/scientific principles alongside the overall system improvement enhancement techniques at the macro and micro scale are highlighted. Furthermore, the review analyzes the impact of significant physical factors that alter or restrict the efficiency of IHSE, as well as their connection and potential regulation. In addition, a comprehensive study of emerging sustainable applications for insight into the design and optimization of IHSE is provided for scientists from different fields. Lastly, the current challenges and future perspectives of interdisciplinary IHSE for large-scale applications are emphasized.
The enhancement of the molecular Raman signal in plasmon-assisted surface-enhanced Raman scattering (SERS) results from electromagnetic and chemical mechanisms, the latter determined to a large extent by the chemical interaction between the molecules and the hosting plasmonic nanoparticles. A precise quantification of the chemical mechanism in SERS based on quantum chemistry calculations is often challenging due to the interplay between the chemical and electromagnetic effects. Based on an atomistic description of the SERS signal, which includes the effect of strong field inhomogeneities, we introduce a comprehensive approach to evaluate the chemical enhancement in SERS, which conveniently removes the electromagnetic contribution inherent to any quantum calculation of the Raman polarization. Our approach uses density functional theory (DFT) and time-dependent DFT to compute the total SERS signal, together with the electromagnetic and chemical enhancement factors. We apply this framework to study the chemical enhancement of biphenyl-4,4′-dithiol embedded between two gold clusters. Although we find that for small clusters the total SERS enhancement is mainly determined by the chemical mechanism, our procedure enables removal of the electromagnetic contribution and isolation of the contribution of the bare chemical effect. This approach can be applied to reproduce and understand Raman line activation and strength in practical and challenging SERS configurations such as in plasmonic nano- and pico-cavities.
Polarizability (α) is a fundamental property which measures the tendency of the electron cloud of an atom, ion, or molecule to be distorted by electric field. Polarizability contributes to important physical properties such as molecular interactions or dielectric constants; thus, it is essential to have accurate polarizabilities in molecular simulations. However, it remains a challenge to develop polarizable force fields (FFs) for ions in computational chemistry. In particular, a comprehensive set of polarizabilities for ions has not been derived. Herein, we derived a systematic set of polarizabilities for atoms and ions across the periodic table based on high-level quantum mechanics calculations. These values have excellent agreement with experimental data. Furthermore, we examined the relationship between the obtained polarizabilities and the van der Waals (VDW) radii (RVDW) that we previously determined (J. Chem. Theory Comput., 2023, 19, 2064). Two relationships, RVDW ∝ α1/7 and RVDW ∝ α1/3, proposed in previous studies were examined in the present work. Our results indicated the former relationship, which was derived based on the quantum harmonic oscillator model, prevails for atoms and cations, but neither relationship provides a satisfactory fit for anions. This is consistent with the tight-binding nature of the electrons in atoms and cations, while it is more challenging to quantify the polarizabilities of anions because of their more dispersed electron clouds. Moreover, we compared different approaches to determine the dispersion coefficients, including the London equation, Slater-Kirkwood equation, symmetry-adapted perturbation theory (SAPT) calculations, and time-dependent density functional theory method, along with the approach based on VDW constants. Our results indicated that although different approaches predict deviated magnitudes for the dispersion coefficients, their predictions are highly correlated, implying that each of these approaches can be used to evaluate dispersion interactions after proper scaling. Finally, we have developed a parametrization strategy for the 12-6-4 model based on the obtained insights. We specifically compared the performance of the 12-6-4 model with SAPT and SobEDA analyses to model interactions involving Na+/Mg2+ and various ligands containing He, Ne, Ar, H2O, NH3, [H2PO4]-, and [HPO4]2-. Our results demonstrate that the 12-6-4 parameters effectively reproduce both the total interaction energy and the individual energy components (electrostatics, exchange-repulsion, dispersion, and induction), highlighting the physical robustness of the 12-6-4 model and the effectiveness of our parametrization approach. This study has significant implications for advancing the development of next-generation ion models and polarizable FFs.
Sondre G. IVELAND, Alexander WESTBYE, Jorge M. MARCHETTI
et al.
Post-combustion CO2 capture is a promising method for removing CO2 from processes where emissions cannot be mitigated by renewable energy input and where the chemical reactions required for production emit CO2, e.g. calcination of calcium carbonate (CaCO3) for cement production. One promising capture method is carbon capture in molten salts (CCMS). CCMS is a thermal swing gas-liquid process that utilizes CaO carbonation to absorb CO2. The molten salt used in this work is 15 wt% CaO in eutectic CaCl2-CaF2 (86.2 : 13.8 wt%). The CaCl2-CaF2-CaO system has been found to have high cyclic absorption capacity (0.6 g CO2/g CaO), though reaction kinetics has yet to be studied. By utilizing a novel experimental setup, data is collected, and a kinetic model is developed, which can be used in a techno-economic evaluation. The model proposes a simplified description of the CaCl2-CaF2-CaO system, with the assumption that the reaction is a first order elementary reaction where CaO and CO2 react to form CaCO3 without any solubility of CO2 in the molten salt. CO2 concentration, temperature, wt% CaO and surface area of molten salt are parameters in the proposed kinetic model. The result is a kinetic model that accurately fits the experimental data with an R2 value above 0.98. It has been found that increasing the CO2 concentration and decreasing the temperature yield a higher CaO to CaCO3 equilibrium conversion.
We have developed a gold recovery method utilizing the thiosulfate leaching and cementation onto silicon (Si) powder. In this process, copper (oxidizing agent for gold dissolution) was also recovered after gold recovery. In this work, we tried to monitor the recovery behavior in order to improve selectivity of metals. For experimentation, an ammonium thiosulfate solution containing 1 mM (M: mol dm−3) sodium gold(I) sulfite and 5 mM copper(II) sulfate was prepared (pH 13). We immersed a gold wire in the solution and measured the rest potential during the recovery process using Si powder. The potential of gold wire shifted to negative direction at the start and end of gold and copper recovery. We discussed the potential shift by measuring polarization curves of gold wire in the ammonium thiosulfate solution under various conditions. The efficient recovery of high-purity gold would be achieved by monitoring the potential of gold.
For the first time, a physicochemical model of the formation of poorly soluble compounds in the kidney nephron was developed on the basis of a mathematical description of the ideal displacement reactor. As a result of mathematical modeling, it was found that under normal physiological conditions, the formation of a solid phase is not the dominant process, which explains the absence of crystalline formations in the kidneys in healthy people. An increase in the concentration of precipitate-forming ions, corresponding to certain conditions of the human body, leads to the occurrence of local high supersaturations in certain areas of the nephron, which can lead to the formation of solid phase nuclei, their fixation and further growth. It is shown that the calculations of material balances, flow movements, as well as the concentration profiles of components in the nephron determine the possibility of predicting the behavior of the model system with variations in the parameters and conditions that affect the course of the crystallization process (concentration, fluid flow, hydrodynamic regime, etc.), which will allow developing effective methods for the prevention and treatment of urolithiasis, including the dissolution of already formed aggregates.
Abstract Multiphase flow in nanoporous media is ubiquitous in geophysics, physical chemistry, and bioengineering. The underlying mechanisms of two-phase flow are of great importance in the prediction of water and oil flow in shale nanoporous media. In this work, we use molecular dynamic simulations to investigate a laminar type oil–water two-phase flow (OW2PF) in quartz nanopores. We find that in nanochannels, due to liquid–liquid slip, the enhancement in oil phase flow may not be neglected. As water film thickness and pore size increase, such enhancement decreases gradually. According to MD results, a new hydrodynamic flow model considering fluid distributions, heterogeneous fluid properties, liquid-wall interaction, and liquid–liquid slip is proposed and compared to MD results and other hydrodynamic flow models. While previous hydrodynamic flow models generally underestimate oil phase flow in a laminar type OW2PF in quartz nanopores, our model shows an excellent agreement with MD simulations for a wide range of pore sizes. Our work could shed some lights into flow mechanism of a laminar type OW2PF in nanoporous media and provide insights into flow modeling development in shale oil exploitation.
Bayou, Naima, Aït-Amar, Hamid, Belkhiri, Samir
et al.
The present work deals with the investigation of the use of the elaborated aluminophosphate (AlPO$_{4}$-5) and silico-aluminophosphate (SAPO-5) materials, in uranium sorption from aqueous solution and real effluents obtained from Nuclear Research Center of Draria, Algiers, Algeria. The surface charge and acidic–basic character of AlPO$_{4}$-5 and SAPO-5 is investigated by the determination of point of zero charge. Batch adsorption experimental studies are carried out to evaluate the influence of initial uranium concentration, final solution pH, contact time, solid-to-liquid ratio and temperature. A maximum adsorption capacity of 61.96 and 74.10 mg/g was obtained for AlPO$_{4}$-5 and SAPO-5 respectively, at pH 7 with an adsorbent ratio of 0.1/150 g/ml and an equilibrium time of 120 min. Kinetic models (pseudo-first order, pseudo-second order and Weber–Morris) are applied to find the mechanism for the removal of uranium ions, experimental data are analyzed by equilibrium models (Langmuir, Freundlich, Dubinin–Radushkevich and Temkin). Modeling sorption results show that uranium sorption is a chemical and endothermic process. The results showed that AlPO$_{4}$-5 and SAPO-5 are effective materials for the removal of uranium (VI) ions.
Abstract Since major limitations of the Dye-Sensitized Solar Cells (DSSCs) efficiency are assumed to come from (i) the low resistivity of the generally used TiO2 (ρ = 1 Ω.cm) and (ii) the undesired electron-hole recombination at the semiconductor/dye-electrolyte interfaces, the development of N-doped TiO2 semiconductor (TiO2:N) has attracted considerable interest. However, the synthesis of this material still remains a challenge as it is difficult to monitor (i) the doping level and (ii) the position of the nitrogen atoms into the titanium oxide lattice. In this context, the combination of Reactive Magnetron Sputtering (RMS) and Ion implantation (II) recently allowed to finely control the nitrogen chemistry of N-doped TiO2 materials. However, the structural properties, such as the crystalline constitution and morphology of the implanted materials are of crucial interest for the intended application. Therefore, we performed a parametric study of the ion beam parameters on the physical and chemical properties of TiO2:N in the aim of charge transport application in DSSCs and the results were supplemented by a simulation tool (i.e. TRIDYN software), allowing to distinguish this work from the others. Briefly, we observed that the sputtering of the ion implanted layer prevails with low accelerating voltages while the ion implantation process and its intrinsic effects are observed for high accelerating voltage conditions. We also demonstrated that the sputtering effect issue can be quite easily avoided for low dose conditions.