jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: W. Saadi | Achoik Yahya | Souad Souissi-Najar | Abdelmottaleb Ouederni
Source: Research Square (preprint, 2024-02-08)
Field: Chemistry — Analytical Chemistry

2-Nitrophenol removal and regeneration studies of pomegranate peels activated carbon Abstract In this paper, activated carbon-based pomegranate peels was used as a new adsorbent for 2-Nitrophenol adsorption from an aqueous solution instead of the commercial adsorbent Chemviron. Liquid-phase adsorption experiments were conducted, and the maximum adsorptive capacity was determined. The effect of the experimental parameters, namely, initial concentration, solution pH, particle size, temperature, and contact time, were traced. The equilibrium data were mathematically modeled, using the Langmuir, Freundlich, and Temkin adsorption models. The Kinetic data suited the Pseudo-first- order and Pseudo-second-order models at different initial concentration values and particle sizes. The thermodynamic study confirmed that the adsorption process was exothermic and spontaneous and the energy relations substantiated the favorability of adsorption on the prepared activated carbon, leading us to conclude that the adsorption process of the phenolic compound from the activated carbon obtained was physical. Pomegranate peels activated carbon regeneration could be performed using hot distilled water. Regeneration (biology) ; Activated carbon ; Nitrophenol ; Chemistry ; Pulp and paper industry ; Cell biology ; Adsorption ; Biology ; Biochemistry ; Organic chemistry ; Engineering ; Catalysis Dye analysis and toxicity ; Potato Plant Research ; Adsorption and biosorption for pollutant removal
Authors: Khalida Naseem | Sana Asghar | Kiky Corneliasari Sembiring | Mohammad Ehtisham Khan | Asima Hameed | Shazma Massey | Warda Hassan | Aneela Anwar | Haneef Khan | F. H. Shair
Source: Toxicology Research (article, 2024-09-02)
Field: Materials Science — Materials Chemistry

Fabrication of bio-inorganic metal nanoparticles by low-cost lychee extract for wastewater remediation: a mini-review Different techniques such as FTIR, UV-visible, XRD, SEM, EDX, and TEM adopted for the analysis of biogenic synthesis of mNPs have also been discussed in detail. Applications of mNPs: Applications of these prepared mNPs in various fields due to their antimicrobial, antiinflammatory, anticancer, and catalytic activities have also been described in detail. Nanoparticle ; Metal ions in aqueous solution ; Nanotechnology ; Reducing agent ; Chemistry ; Wastewater ; Metal ; Environmental remediation ; Polyphenol ; Solvent ; Fourier transform infrared spectroscopy ; Materials science ; Fabrication ; Nuclear chemistry ; Chemical engineering ; Organic chemistry ; Waste management ; Biology Nanoparticles: synthesis and applications
Authors: Stevan Stupar | Pavel Otřísal | Negovan Ivanković | Dušan Mijin | Marija M. Vuksanović | Radmila Jančić Heinemann | Aleksandra Samolov
Source: Science of Sintering (article, 2024-01-01)
Field: Chemistry — Inorganic Chemistry

Sintered magnesium ferrite particles in decolorization of anthraquinone dye AV 109: Combination of adsorption and fenton process Magnesium ferrite (MgFe2O4) particles were synthetized by sol-gel method and used in the decolorization of the Acid Violet 109 (anthraquinone dye, AV109) water solutions' by combination of adsorption and heterogeneous Fenton process. The material's morphology and elemental analysis of the surface were revealed by Scanning electron microscopy and Energy Dispersive Spectroscopy (SEM/EDS). The X-Ray Diffraction (XRD) technique was used to analyze the crystallographic phase. In the first part of the decolorization experiment, the adsorption ability of the synthesized particles was investigated. During the adsorption study influence of pH was investigated. In the second part of the decolorization experiment, the effects of the various parameters on the Fenton process were studied such as the initial concentrations of hydrogen peroxide, dye, and magnesium ferrite particles. Influence of magnesium ferrite particles structure, pH value and reaction temperature were also investigated. The decolorization reaction was followed by UV-Visible (UV-Vis) spectrophotometry. At optimal conditions, the dye decolorization was 99.1% (55.4% by adsorption and 43.7% by the Fenton process). Both the adsorption and the Fenton process obey second-order kinetics. Adsorption ; Ferrite (magnet) ; Anthraquinone ; Materials science ; Magnesium ; Process (computing) ; Chemical engineering ; Metallurgy ; Chemistry ; Composite material ; Organic chemistry ; Engineering Pigment Synthesis and Properties
Source: Letters in Applied NanoBioScience (article, 2024-03-30)
Field: Chemistry — Analytical Chemistry

Removal of a Toxic Herbicide 2,4,5-trichlorophenoxyacetic Acid Using a Recycling Eco-friendly Adsorbent In this work, we are interested in the elimination of the herbicide 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) using an adsorption process onto an eco-friendly material named LDH [Zn2-Al-CO3] calcined at 500 °C. Indeed, dissolving calcined LDH in a pollutant solution allows the retention of herbicide in its anionic form. The choice of LDH based on Zn and Al was conditioned by their low cost, ease of synthesis, not toxic to the environment, and not generating sludge. Several parameters were considered: the retention of pollutants by LDH nanomaterial is improved for a pH range between 5 and 6, the equilibrium retention is obtained after 6 hours, and retention kinetics follows the pseudo-second-order model. The isotherms are of L-type, and they follow the Freundlich model; retention capacity reaches 75 % for a mass ratio 2,4,5-T/CLDH of 0.66, and the maximum amount retained of the dye is 590 mg/g. X-ray diffraction showed that the synthesized matrix is crystallized in a lamellar structure; the adsorption is governed by intercalation of the herbicide in its anionic form between the reconstructed LDH sheets. Infrared analysis indicated the appearance of the characteristic bands of pollutants in the matrix spectrum, thus confirming his retention. Additionally, SEM analysis exposed the lamellar character of the phase achieved before and after the intercalation of the pollutant. LDH adsorbent can be considered a better nanomaterial with a high capacity of retention, has a low cost, and is eco-friendly. Adsorption ; Environmentally friendly ; Chemistry ; Waste management ; Environmental chemistry ; Environmental science ; Biology ; Organic chemistry ; Ecology ; Engineering Dye analysis and toxicity ; Water Quality Monitoring and Analysis ; Inorganic and Organometallic Chemistry
Authors: Alexander Schlaich | Jean‐Louis Barrat | Benoît Coasne
Source: arXiv (Cornell University) (preprint, 2024-06-05)
Field: Materials Science — Materials Chemistry

Theory and Modeling of Transport for Simple Fluids in Nanoporous Materials: From Microscopic to Coarse-Grained Descriptions We present the state-of-the-art theoretical modeling, molecular simulation, and coarse-graining strategies for the transport of gases and liquids in nanoporous materials (pore size 1-100 nm). Special emphasis is placed on the transport of small molecules in zeolites, active carbons, metal-organic frameworks, but also in nanoporous materials with larger pores such as ordered and disordered mesoporous oxides. We present different atomistic and mesoscopic methods as well as the theoretical formalisms. Attention is given to the investigation of different molecular transport coefficients - including the self, collective and transport diffusivities - but also to the determination of free energy barriers and their role in overall adsorption/separation process rates. We also introduce other available approaches such as hierarchical simulations and upscaling strategies. This review focuses on simple fluids in prototypical nanoporous materials. While the phenomena covered here capture the main physical mechanisms in such systems, complex molecules will exhibit additional specific features. For the sake of clarity and brevity, we also omit multicomponent systems (e.g. fluid mixtures, electrolytes, etc.) and electrokinetic effects arising when charged systems are considered (ionic species, charged surfaces, etc.), both of which add to the complexity. Nanoporous ; Materials science ; Computer science ; Nanotechnology Nanoporous metals and alloys
Authors: Juan Carlos Gallegos | J. Manríquez | R. Rodrı́guez | S. Vargas | Domingo Rangel
Source: Journal of Electrochemical Science and Technology (article, 2024-02-06)
Field: Materials Science — Polymers and Plastics

Steady-State and Transient Response Analysis of DSSC Based on Electron Diffusion Coefficient and Chemical Capacitance &lt;p&gt;A study of the transition from transitory state to steady state in DSSCs based on natural dyes is presented; cochineal was used as dye and &lt;italic&gt;Li&lt;/italic&gt;&lt;sup&gt;+&lt;/sup&gt;, &lt;italic&gt;Na&lt;/italic&gt;&lt;sup&gt;+&lt;/sup&gt;, and &lt;italic&gt;K&lt;/italic&gt;&lt;sup&gt;+&lt;/sup&gt; were the ions added to the electrolyte. The photocurrent profiles were obtained as a function of time. Several DSSCs were prepared with different cations and their role and the transitory-to-steady transition was determined. A novel hybrid charge carrier source model based on the Heaviside function &lt;italic&gt;H&lt;/italic&gt;(&lt;italic&gt;t&lt;/italic&gt;) and the Lambert-Beer law, was developed and applied to analysis of the transient response of the output photocurrent. Additionally, the maximum effective light absorption coefficient &lt;italic&gt;α&lt;/italic&gt; and the electronic extraction rate &lt;italic&gt;κ&lt;/italic&gt; for each ion were determined: &lt;italic&gt;α&lt;/italic&gt;&lt;italic&gt;&lt;sub&gt;Li&lt;/sub&gt;&lt;/italic&gt;&lt;sub&gt;&lt;sup&gt;+&lt;/sup&gt;&lt;/sub&gt;, &lt;italic&gt;&lt;sub&gt;Na&lt;/sub&gt;&lt;/italic&gt;&lt;sub&gt;&lt;sup&gt;+&lt;/sup&gt;&lt;/sub&gt;, &lt;italic&gt;&lt;sub&gt;K&lt;/sub&gt;&lt;/italic&gt;&lt;sub&gt;&lt;sup&gt;+&lt;/sup&gt;&lt;/sub&gt; = (0.486, 0.00085, 0.1126) cm&lt;sup&gt;−1&lt;/sup&gt;, and also the electronic extraction rate &lt;inline-formula&gt;&lt;mml:math id="m1" display="inline"&gt;&lt;mml:semantics id="sm1"&gt;&lt;mml:mrow&gt;&lt;mml:msubsup&gt;&lt;mml:mrow&gt;&lt;mml:mi&gt;κ&lt;/mml:mi&gt;&lt;/mml:mrow&gt;&lt;mml:mrow&gt;&lt;mml:mi&gt;e&lt;/mml:mi&gt;&lt;mml:mi&gt;x&lt;/mml:mi&gt;&lt;mml:mi&gt;t&lt;/mml:mi&gt;&lt;mml:mo&gt;.&lt;/mml:mo&gt;&lt;/mml:mrow&gt;&lt;mml:mrow&gt;&lt;mml:mi&gt;L&lt;/mml:mi&gt;&lt;mml:msup&gt;&lt;mml:mrow&gt;&lt;mml:mi&gt;i&lt;/mml:mi&gt;&lt;/mml:mrow&gt;&lt;mml:mo&gt;+&lt;/mml:mo&gt;&lt;/mml:msup&gt;&lt;/mml:mrow&gt;&lt;/mml:msubsup&gt;&lt;/mml:mrow&gt;&lt;/mml:semantics&gt;&lt;/mml:math&gt;&lt;/inline-formula&gt;, &lt;italic&gt;Na&lt;/italic&gt;&lt;sup&gt;+&lt;/sup&gt;, &lt;italic&gt;K&lt;/italic&gt;&lt;sup&gt;+&lt;/sup&gt; = (1410, 19.07, 19.69) cm s&lt;sup&gt;−1&lt;/sup&gt;. The impedance model using Fick&lt;italic&gt;’&lt;/italic&gt;s second law was developed for carrier recombination to characterize the photocurrent.&lt;/p&gt; Chemistry Conducting polymers and applications ; Electrochemical Analysis and Applications ; Photochromic and Fluorescence Chemistry
Authors: Daegwon Noh | Eunsoon Oh
Source: Polymers (article, 2024-03-26)
Field: Materials Science — Materials Chemistry

Estimation of Environmental Effects and Response Time in Gas-Phase Explosives Detection Using Photoluminescence Quenching Method Detecting the presence of explosives is important to protect human lives during military conflicts and peacetime. Gas-phase detection of explosives can make use of the change of material properties, which can be sensitive to environmental conditions such as temperature and humidity. This paper describes a remote-controlled automatic shutter method for the environmental impact assessment of photoluminescence (PL) sensors under near-open conditions. Utilizing the remote-sensing method, we obtained environmental effects without being exposed to sensing vapor molecules and explained how PL intensity was influenced by the temperature, humidity, and exposure time. We also developed a theoretical model including the effect of exciton diffusion for PL quenching, which worked well under limited molecular diffusions. Incomplete recovery of PL intensity or the degradation effect was considered as an additional factor in the model. Photoluminescence ; Explosive material ; Materials science ; Peacetime ; Quenching (fluorescence) ; Humidity ; Diffusion ; Shutter ; Environmental science ; Gas phase ; Exciton ; Intensity (physics) ; Analytical Chemistry (journal) ; Optoelectronics ; Optics ; Meteorology ; Environmental chemistry ; Fluorescence ; Thermodynamics ; Chemistry ; Physics Luminescence and Fluorescent Materials ; Advanced Chemical Sensor Technologies ; Spectroscopy Techniques in Biomedical and Chemical Research
Authors: R. L. Nkepsu Mbitou | F. Goujon | Alain Dequidt | Benoit Latour | Julien Devémy | Nicolas Martzel | Patrice Hauret | Patrice Malfreyt
Source: ChemPhysChem (article, 2024-04-26)
Field: Materials Science — Materials Chemistry

Autohesion Mechanisms at Interfaces Between Random Copolymer Melts: Mesoscopic Simulations with Realistic Coarse‐Grained Models The increase in welding time during the interdiffusion of a pair of non reacting random copolymer melts favors the strength rate of healing at the interface. Furthermore, the diffusion kinetic during the interpenetration of copolymer chains across the interface is strongly dependent on molecular weight. In this paper we perform mesoscopic simulations with realistic coarse grain models to study the autohesion mechanism across the interface between slightly entangled styrene-butadiene random copolymer melts. Mesoscopic physics ; Copolymer ; Materials science ; Statistical physics ; Chemical physics ; Nanotechnology ; Chemistry ; Physics ; Condensed matter physics ; Polymer ; Composite material Block Copolymer Self-Assembly ; Material Dynamics and Properties ; Polymer crystallization and properties
Authors: Howard E. Sims | Robin M. Orr
Source: Frontiers in Nuclear Engineering (article, 2024-04-17)
Field: Chemistry — Inorganic Chemistry

Radiation chemical processes in the water layer on the surface of PuO2 It is generally accepted that radiolysis of water on the surface of PuO 2 by alpha particles is the source of H 2 which can cause pressurisation in sealed storage containers if the material is not adequately conditioned before packing. The mechanisms for this have not been discussed in detail previously. Radiolysis mechanisms of bulk water are summarised and then applied to water at the surface of PuO 2 . It is shown that the radiolysis processes occurring on timescales of less than 1 ps after energy deposition could have an impact on the storage behaviour of the PuO 2 and the potential gas volume generated. Some of the radiolysis products are highly reactive and would be expected to react with plutonium at the surface, affecting the usual water radiolysis processes. A corollary of this observation is that the surface should not be considered a completely crystalline PuO 2 solid. It is also highlighted that whilst there are significant uncertainties in the radiolysis process at the PuO 2 surface there are also significant uncertainties in H 2 formation mechanisms in bulk water. Finally, methods to model the radiolysis process at the surface and the prospects for predictive models are briefly discussed with suggestions for future areas of development. Radiolysis ; Chemistry ; Plutonium ; Surface layer ; Surface water ; Radiochemistry ; Layer (electronics) ; Radical ; Environmental science ; Organic chemistry ; Environmental engineering Radioactive element chemistry and processing ; Nuclear Materials and Properties ; Radioactive contamination and transfer
Authors: Aleksey Kudreyko | Vladimir G. Chigrinov | Arina Perestoronina
Source: Crystals (article, 2024-12-28)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Photoinduced Interactions in Thin Films of Azo Dyes and Planar-Aligned Nematic Liquid Crystal Properties of surface anchoring depend on the absorbed exposure energy and various potential interactions associated with liquid crystal and azo dye layers. In this study, we investigate a model of dispersion, steric and photoinduced interactions with the goal of providing a qualitative and quantitative description of orientationally ordered hard uniaxial liquid crystals and azo dye molecules. By using the Onsager theory, we estimated the effect of excluded volume. Typical repulsive potentials between liquid crystal and azo dye molecules are displayed graphically. The presence of statistical dispersion in molecular alignment of liquid crystals leads to potential wells in dipole–dipole interactions. Our mean field theory investigation of dipole–dipole interactions shows that the anchoring free energy is governed by the net interaction energy associated with the averaged dipole moments of liquid crystal and azo dye molecules, photoaligned surface dipole moments, and local charge densities. We also use the Fokker–Planck equation to show that rotational diffusion is described by the effective mean field potential, which includes photoinduced and van der Waals interactions. Our findings underscore the potential of mean field theory for intermolecular couplings in photoaligned surfaces, opening up new pathways of molecular design for a broad range of parameters. Liquid crystal ; Materials science ; Planar ; Thin film ; Optoelectronics ; Optics ; Crystallography ; Nanotechnology ; Chemistry ; Physics ; Computer graphics (images) ; Computer science Liquid Crystal Research Advancements ; Photonic Crystals and Applications ; Photochemistry and Electron Transfer Studies
Authors: Sujeet Dutta | Andréi Nossov | Anne Galarneau | Youcef Didi | Bilel Said | Renaud Denoyel | Véronique Wernert | Benoît Coasne | Flavien Guenneau
Source: The Journal of Physical Chemistry Letters (article, 2024-03-15)
Field: Chemistry — Inorganic Chemistry

Apparent Anomalous Temperature Dependence of Self-Diffusion Studied by Pulsed-Field Gradient Nuclear Magnetic Resonance and Thermodynamic Modeling The self-diffusivity of cyclohexane and <i>n</i>-octane adsorbed in hierarchical zeolite monoliths has been investigated by using PFG-NMR. In these samples, the intrinsic FAU-X zeolite microporosity combines with a complex macroporous network composed of aggregated zeolite nanocrystals. As temperature is increased, cyclohexane self-diffusivity apparently decreases, reaches a minimum, and then starts increasing upon further increasing the temperature. Such striking, i.e., non-Arrhenius, temperature dependence is not observed for <i>n</i>-octane in the same samples and for cyclohexane adsorbed in purely microporous FAU-X. Through thermodynamic modeling, we show that this anomalous behavior can be rationalized by considering the evolution in the adsorbate populations when changing the temperature. In more detail, we show that the slow and fast diffusing species present in the microporosity and secondary porosity arising from the packing of zeolite nanocrystals vary significantly with a strong impact on the effective diffusivity. Applying the temperature evolution of their relative fractions to a simple two-phase diffusion model helps obtain insights into the physicochemical factors responsible for the complex behavior of effective self-diffusivity in hierarchical zeolites. Thermal diffusivity ; Cyclohexane ; Microporous material ; Zeolite ; Diffusion ; Pulsed field gradient ; Arrhenius equation ; Thermodynamics ; Nanocrystal ; Adsorption ; Porosity ; Octane ; Materials science ; Chemical physics ; Chemistry ; Physical chemistry ; Activation energy ; Nanotechnology ; Organic chemistry ; Catalysis Zeolite Catalysis and Synthesis ; Advanced NMR Techniques and Applications ; NMR spectroscopy and applications
Authors: Mangesh Bhendale | Jayant K. Singh | Alessio Zaccone
Source: arXiv (Cornell University) (preprint, 2024-03-27)
Field: Materials Science — Materials Chemistry

Shear-induced diffusivity in supercooled liquids The Taylor-Aris theory of shear diffusion predicts that the effective diffusivity of a tracer molecule in a sheared liquid is enhanced by a term quadratic in the shear rate. In sheared supercooled liquids, instead, the observed enhancement is linear in the shear rate. This is a fundamental observation for the physics of nonequilibrium liquids. Here, we derive a formula for the effective molecular diffusivity in supercooled liquids under shear flow based on the underlying Smoluchowski equation with shear (Smoluchowski diffusion-convection equation) with an energy barrier due to the crowded energy landscape. The obtained formula recovers the effective diffusivity with a correction term linear in the shear rate, in reasonable agreement with results from numerical simulations of different liquids as well as with earlier experimental results on shear melting of colloidal glass. The theory predictions are compared with molecular simulations of supercooled water and supercooled Lennard-Jones liquids. The comparison suggests that the predicted enhancement of diffusivity is inversely proportional to temperature and directly proportional to the zero shear viscosity. Supercooling ; Thermal diffusivity ; Shear (geology) ; Materials science ; Thermodynamics ; Geology ; Statistical physics ; Physics ; Composite material Material Dynamics and Properties
Authors: Xudong Wang | Emma Norgate | Junxiao Dai | Florian Benoit | Jason M. D. Kalapothakis | Anthony W. T. Bristow | R. England | Perdita E. Barran
Source: ChemRxiv (preprint, 2024-02-07)
Field: Chemistry — Spectroscopy

Conformational landscapes of rigid and flexible molecules explored with variable temperature ion mobility-mass spectrometry Understanding the effect of temperature to the structural integrity and dynamics of proteins has relevance for many areas including biotechnology and the maintenance of a stable food supply for the climate emergency. The methods that can explore changes in structure as a function of sub-ambient temperature are scant, and yet many drugs are stored at such temperatures. Here we show how variable temperature ion mobility-mass spectrometry (VT-IM-MS) can provide the role of temperature on conformational landscapes in the form of collision cross sections at discrete temperatures. To delineate collision effects from structural change we report measurements made on four molecules that possess different degrees of rigidity namely: poly (L-lysine) (PLL) dendrimer, ubiquitin, β-casein and α-synuclein from 190-350K. We show that the PLL dendrimer varies with temperature consistent with collision theory, and conclude, as expected, its structure does not alter significantly over this range. By contrast, the structure of each protein is altered by the temperature of the drift gas, with notable unfolding to all charge states at 350 K and also at 250 K, following predicted in vitro stability curves, and with conformational variation that gives qualitative insights to the effect of temperature on the free energy landscape of these proteins. We also show that we can kinetically trap unfolding intermediates at drift temperatures of 210 K and 190 K on a millisecond experimental time scale. For alpha-synuclein, the 13+ ions present two distinct conformers and VT-IM-MS measurements allow us to calculate the transition rate and activation energies for conversion between these. These data exemplify the capability of VT-IM-MS to provide insights to thermodynamics involved in conformational restructuring. Ion-mobility spectrometry ; Chemistry ; Energy landscape ; Mass spectrometry ; Chemical physics ; Conformational isomerism ; Molecule ; Atmospheric temperature range ; Ion ; Millisecond ; Conformational change ; Biophysics ; Thermodynamics ; Analytical Chemistry (journal) ; Physics ; Stereochemistry ; Organic chemistry ; Chromatography ; Biochemistry Mass Spectrometry Techniques and Applications ; Forensic Toxicology and Drug Analysis ; Metabolomics and Mass Spectrometry Studies