jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Cristina E. Almeida‐Naranjo | Jeniffer Cuestas | Víctor H. Guerrero | Cristina Alejandra Villamar
Source: Water (article, 2024-01-05)
Field: Materials Science — Materials Chemistry

Efficient Decontamination: Caffeine/Triclosan Removal using Rice Husk in Batch and Fixed-Bed Columns Abundant, easily accessible, and low-cost agro-industrial residues represent attractive alternatives for removing emerging contaminants from water. In this work, the aqueous adsorption of caffeine/triclosan onto rice husk (RH) was studied in batch and continuous processes. For this purpose, adsorbents with three particle size ranges (120–150, 300–600, 800–2000 µm) were prepared and evaluated. The composition, structure, surface morphology, functionality, and specific surface area of the RH biosorbents were determined. This characterization revealed that RH primarily consists of lignin, cellulose, and hemicellulose, making up to 80.1% of its composition. RH also exhibited an irregular surface, with several functional groups (OH, C=O, CH, C=C, C-OH), and a relatively small specific surface area (1.18 m2/g). Batch tests were carried out using different RH sizes, doses (1–50 g/L), and contact times (5–300 min), using 20 mL of caffeine/triclosan solutions (30 mg/L). Tests were conducted to fit the most adequate kinetics and isotherm models. The optimal doses (g/L) for caffeine and triclosan removal were 4.5 and 1.5 with small RH, 8.5 and 2.5 with medium RH, and 50.0 and 10.0 with large RH, respectively. The optimal contact times for all three particle sizes were 180 and 60 min. Triclosan removal was greater than that of caffeine (2.5–25.5%) with all three particle sizes, requiring less adsorbent (2.5–5.0 times) and shorter times (3 times). The experimental data fit better the Sips isotherm and Elovich kinetics models. The small (120–150 µm) particles achieved the highest caffeine/triclosan batch adsorption capacities (6.3/28.6 mg/g). Continuous tests were performed on fixed-bed columns of 1 cm in diameter, packed with 4, 5, and 8 cm of RH, operated with hydraulic loading rates between 2 and 4 m3/m2day. Small particles also reached the highest adsorption capacity in the removal of caffeine (352.7 mg/L) and triclosan (3797.2 mg/L), and the experimental data were well-fitted to the Bohart–Adams model. The research results not only demonstrate the effective removal of contaminants but also illustrate the versatility and applicability of rice husk in various conditions and systems. Husk ; Triclosan ; Adsorption ; Chemistry ; Aqueous solution ; Human decontamination ; Cellulose ; Particle size ; Hemicellulose ; Response surface methodology ; Langmuir adsorption model ; Caffeine ; Specific surface area ; Nuclear chemistry ; Chromatography ; Waste management ; Organic chemistry ; Catalysis ; Botany Covalent Organic Framework Applications ; Adsorption and biosorption for pollutant removal ; Microplastics and Plastic Pollution
Authors: Angela Yang | Brian E. McKenzie | Benjamin Pavlat | Eric S. Johnson | Aditya S. Khair | Stephen Garoff | Robert D. Tilton
Source: Langmuir (article, 2024-05-01)
Field: Chemistry — Physical and Theoretical Chemistry

Diffusiophoretic Transport of Charged Colloids in Ionic Surfactant Gradients Entirely below versus Entirely above the Critical Micelle Concentration When placed in an ionic surfactant gradient, charged colloids will undergo diffusiophoresis at a velocity, <i>u</i><sub>DP</sub> = <i>M</i><sub>DP</sub>∇ ln <i>S</i>, where <i>M</i><sub>DP</sub> is the diffusiophoretic mobility and <i>S</i> is the surfactant concentration. The diffusiophoretic mobility depends in part on the charges and diffusivities of the surfactants and their counterions. Since micellization decreases surfactant diffusivity and alters charge distributions in a surfactant solution, <i>M</i><sub>DP</sub> of charged colloids in ionic surfactant gradients may differ significantly when surfactant concentrations are above or below the critical micelle concentration (CMC). The role of micelles in driving diffusiophoresis is unclear, and a previously published model that accounts for micellization suggests the possibility of a change in the sign of <i>M</i><sub>DP</sub> above the CMC [Warren, P. B.; . <i>Soft Matter</i> 2019, 15, 278-288]. In the current study, microfluidic channels were used to measure the transport of negatively charged polystyrene colloids in sodium dodecyl sulfate (SDS) surfactant gradients established at SDS concentrations that are either fully above or fully below the CMC. Interpretation of diffusiophoresis was aided by measurements of the colloid electrophoretic mobility as a function of SDS concentration. A numerical transport model incorporating the prior diffusiophoretic mobility model for ionic surfactant gradients was implemented to elucidate signatures of positive and negative diffusiophoretic mobilities and compare with experiments. The theoretically predicted sign of the diffusiophoretic mobility below the CMC was determined to be particularly sensitive to uncertainty in colloid and surfactant properties, while above the CMC, the mobility was consistently predicted to be positive in the SDS concentration range considered in the experiments conducted here. In contrast, experiments only showed signatures of a negative diffusiophoretic mobility for these negatively charged colloids with no change of sign. Colloid diffusiophoretic transport measured in micellar solutions was more extensive than that below the CMC with the same ∇ ln <i>S</i>. Pulmonary surfactant ; Micelle ; Colloid ; Ionic bonding ; Critical micelle concentration ; Chemistry ; Chemical engineering ; Concentration gradient ; Chemical physics ; Chromatography ; Ion ; Organic chemistry ; Aqueous solution ; Biochemistry Electrostatics and Colloid Interactions ; Nanopore and Nanochannel Transport Studies ; Microfluidic and Bio-sensing Technologies
Authors: Wipoo Sriseubsai | Ariya Praemettha
Source: Polymers (article, 2024-12-30)
Field: Materials Science — Polymers and Plastics

Hybrid Natural Fiber Composites of Polylactic Acid Reinforced with Sisal and Coir Fibers This study explored the tensile and impact strength of polylactic acid (PLA) through the incorporation of sisal and coir fibers. Hybrid natural fiber composites were prepared using PLA as the matrix and sisal and coir fibers as the reinforcements. The hybrid composites were prepared with an internal mixer, followed by compression molding. A constrained mixture design was employed to determine the optimal material combinations and their effects on the tensile and impact strength. Confirmatory experiments based on response surface methodology revealed no significant differences in the data means at the 0.05 significance level. PLA reinforced with sisal fibers alone exhibited the highest tensile strength of 75.36 MPa but demonstrated a low impact resistance of 12.94 kJ/m<sup>2</sup> at a 95.22:4.78 (PLA:sisal by volume) ratio. Conversely, the maximum impact resistance of 36.71 kJ/m<sup>2</sup> was achieved with PLA and coir at the same ratio. An optimal blend, consisting of 95.22% PLA, 0.78% sisal, and 4.0% coir by volume, resulted in a tensile strength of 51.08 MPa and an impact strength of 26.59 kJ/m<sup>2</sup>, outperforming other mixtures and pure PLA in the mechanical properties. Additionally, water absorption tests showed that reinforcement with sisal and coir fibers increased both water absorption and stability over 60 h. SISAL ; Coir ; Ultimate tensile strength ; Materials science ; Composite material ; Polylactic acid ; Absorption of water ; Compression molding ; Izod impact strength test ; Fiber ; Natural fiber ; Polymer Natural Fiber Reinforced Composites ; biodegradable polymer synthesis and properties ; Additive Manufacturing and 3D Printing Technologies
Authors: G. Tamil Elakkiya | G. Sundararajan | R. Lakshmipathy | P. Anitha | N. Muruganantham
Source: Bulletin of the Chemical Society of Ethiopia (article, 2024-03-12)
Field: Chemistry — Organic Chemistry

Prolific application of green synthesised CdS nanoparticles for the sequestration of cationic dyes from aqueous solution Synthesis of cadmium sulfide (CdS) nanoparticles using watermelon rind aqueous extract was explored for its effectiveness in eliminating Methylene Blue (MB) and Crystal Violet (CV) dyes from water. The synthesised CdS nanoparticles were characterised with XRD, TEM and EDX and found to be around 10 nm in size with spherical shape. A central composite design was developed to optimise independent variables such as pH, contact time and initial concentrations. The developed quadratic model was found to be significant with p-value &lt;0.0001 and lack of fit &gt;0.005 suggesting the reliability of the model. Isotherm modelling analysis revealed that Langmuir and Freundlich's isotherms provided better explanation for the equilibrium data. The loading capacities of the CdS nanoparticles were found be 227.3 and 185.1 mg g-1, respectively for MB and CV. The experimental data showed a good fit with the pseudo-second-order kinetic model, indicating that chemical reactions were the determining factor in controlling the rate-limiting step. Thermodynamic analyses indicated that the process was spontaneous and exothermic. Desorption and regeneration investigations demonstrated that CdS nanoparticles could be successfully regenerated up to 5 times and reused in the adsorption process. The results conclude that the CdS nanoparticles are capable of remediating water containing cationic dyes. KEY WORDS: Watermelon rind, CdS nanoparticles, Synthetic dyes, Adsorption, RSM Bull. Chem. Soc. Ethiop. 2024, 38(3), 631-645. DOI: https://dx.doi.org/10.4314/bcse.v38i3.7 Chemistry ; Aqueous solution ; Cationic polymerization ; Nanoparticle ; Green chemistry ; Chemical engineering ; Nanotechnology ; Organic chemistry ; Catalysis ; Reaction mechanism Nanomaterials for catalytic reactions ; Chemical Synthesis and Reactions
Authors: Esat Pehlivan | Claes G. Granqvist | Gunnar A. Niklasson
Source: Solar Energy Materials and Solar Cells (article, 2024-03-05)
Field: Materials Science — Polymers and Plastics

Electrochromic nickel-oxide-based thin films in KOH electrolyte: Ionic and electronic effects elucidated by impedance spectroscopy Ni-oxide-based thin films, prepared by sputtering, are investigated by electrochemical impedance spectroscopy in a KOH electrolyte. The films are electrochromic, and an increase of the applied potential leads to a variation from a bleached to a colored state as a result of proton (H+) extraction together with extraction of electrons from the valence band. The complex frequency-dependent impedance displays different features in different potential ranges. At low potentials, where coloration is weak, the spectra give evidence for a constant-phase element in parallel with a leak resistance. At intermediate and high potentials, the impedance spectra indicate the presence of a diffusion process, and a model for anomalous diffusion gives excellent fits to the spectra except in a crossover region. The applicability of this model in a significant part of the studied potential range suggests the presence of a multiple-trapping process for the ions. The potential dependence of the chemical capacitance, as well as the diffusion coefficient of un-trapped ions, are analyzed. The electrochemical density-of-states of the charge-compensating electrons gives indications of the top of the valence band and of a band tail extending into the band gap. Diffusion coefficients are found to increase steeply in the crossover potential region to very high values at high potentials. These features are discussed and related to the electrochromic behavior of Ni-oxide-based thin films. Electrochromism ; Dielectric spectroscopy ; Analytical Chemistry (journal) ; Electrolyte ; Chemistry ; Oxide ; Band gap ; Ionic bonding ; Ion ; Materials science ; Chemical physics ; Electrochemistry ; Optoelectronics ; Physical chemistry Transition Metal Oxide Nanomaterials ; Conducting polymers and applications ; Advanced Memory and Neural Computing
Authors: Tomáš Kročil | Nikola Macháčková | Tomáš Prošek | Thomas Steck | Reza Sharif
Source: Metals (review, 2024-11-12)
Field: Materials Science — Materials Chemistry

Hydrogen Embrittlement of Galvanized Press-Hardened Steels: A Review Press-hardened steels (PHS), as an alternative to traditional steels and aluminum alloys, combine great mechanical performance with low manufacturing costs. PHS are martensitic steels with ultimate tensile strength (UTS) up to 2000 MPa. These steels are commonly coated with zinc-based coatings (PHS GI) consisting of multiple Zn–Fe phases to enhance corrosion resistance. However, similar to all high-strength steels, PHS are known for their elevated susceptibility to hydrogen embrittlement (HE). Absorption of atomic hydrogen into the steel lattice can lead to a transition from a ductile to a brittle fracture mechanism and decrease the stress necessary for fracture initiation. This review examines the microstructure of PHS GI with a focus on how the manufacturing process influences key parameters of the coating. The material’s susceptibility to HE is discussed in the following sections, along with the potential for hydrogen introduction through corrosion in atmospheric environments. The relationship between the content of hydrogen and its effects on fracture behavior is discussed, along with the corrosion behavior of PHS GI. The potential areas for future research and development of PHS GI with increased HE resistance are proposed. Galvanization ; Hydrogen embrittlement ; Metallurgy ; Embrittlement ; Materials science ; Hydrogen ; Forensic engineering ; Engineering ; Composite material ; Corrosion ; Chemistry Material Properties and Failure Mechanisms ; Hydrogen embrittlement and corrosion behaviors in metals ; Welding Techniques and Residual Stresses
Authors: Masatoshi Kimura | Masahiro Ochiai | Xinyi He | Takayoshi Katase | Hidenori Hiramatsu | Hideo Hosono | Toshio Kamiya
Source: EcoEnergy (article, 2024-12-25)
Field: Materials Science — Materials Chemistry

Thermoelectric performance enhancement of environmentally‐friendly SrTiO<sub>3</sub> epitaxial films by hydrogen substitution Abstract Developing high‐efficiency and environmentally‐friendly thermoelectric materials has been a significant challenge. Conventional thermometric materials consist of heavy (toxic) elements to reduce thermal conductivity ( κ ), while we demonstrated light‐element hydride anion (H − ) substitution in SrTiO 3 can largely reduce κ and enhance thermometric efficiency ( ZT ) without heavy elements. In this paper, we succeeded in maximizing the ZT of SrTiO 3− x H x by applying topochemical reaction directly to SrTiO 3 epitaxial films with CaH 2 , which realized wide‐range control of carrier concentration ( n e ) from 1.5 × 10 20 cm −3 to 4.1 × 10 21 cm −3 . The power factor (PF) showed a dome‐shaped behavior with respect to n e , and the maximum PF = 22.5 μW/(cmK 2 ) was obtained at the optimal n e = 3.4 × 10 20 cm −3 . Carrier transport analyses clarified that the carrier mobility was limited by impurity scattering of H‐related impurities in the SrTiO 3− x H x films, while the hydrogen substitution induced a much lower κ of 4.6 W/(mK) than other heavy‐element substituted Sr 1− x La x TiO 3 and SrTi 1− x Nb x O 3 films in the wide n e range, resulting in the higher ZT value of 0.14 in maximum at room temperature. In addition, the ZT increased to 0.17 at 373 K due to the large decrease in κ for a SrTiO 3− x H x film with the hydrogen concentration of 1.2 × 10 21 cm −3 . Further study on H − substitution approach and modulation of the H state in transition metal oxides would lead to development of high ZT environmentally‐friendly thermoelectric materials. Materials science ; Hydride ; Thermoelectric effect ; Impurity ; Hydrogen ; Epitaxy ; Analytical Chemistry (journal) ; Thermoelectric materials ; Thermal conductivity ; Atmospheric temperature range ; Electron mobility ; Nanotechnology ; Optoelectronics ; Metallurgy ; Metal ; Chemistry ; Thermodynamics ; Composite material ; Organic chemistry Advanced Thermoelectric Materials and Devices ; Perovskite Materials and Applications ; Thermal Expansion and Ionic Conductivity
Authors: Junhong Yu | Yadong Han | Yunfan Yang | Hang Zhang | Siyu Fang | Zhengbang Wang | Jianbo Hu
Source: Advanced Optical Materials (article, 2024-05-16)
Field: Chemistry — Inorganic Chemistry

Optical Control of Directional Exciton Migration in Porphyrin‐Based Metal−Organic Frameworks Abstract Porphyrin‐based metal‐organic frameworks (MOFs) have received great attention for solar photochemistry applications. Manipulating the direction of energy (exciton) migration plays an essential role in boosting the light‐harvesting efficiency of porphyrin‐based MOFs. Here, based on the time‐dependent exciton‐exciton annihilation rate, an optical control of directional exciton migration is demonstrated in cobalt‐porphyrin surface‐supported MOF nanofilms (Co‐TCPP SURMOFs). Utilizing photocarrier densities or lattice temperature as the control knob, the dynamic form of exciton migration in Co‐TCPP SURMOFs can be switched between the nearest‐neighbor 1D interaction and the quasi‐isotropic 2D interaction, which is well explained using a diffusion model of exciton‐exciton scattering. This results provide an optical approach to regulating exciton migration in MOFs, which enhances understanding of the excitonic behavior in artificial light harvesters. Porphyrin ; Materials science ; Exciton ; Metal-organic framework ; Metal ; Optical materials ; Optoelectronics ; Nanotechnology ; Photochemistry ; Condensed matter physics ; Physical chemistry ; Metallurgy Metal-Organic Frameworks: Synthesis and Applications ; Porphyrin and Phthalocyanine Chemistry ; Luminescence and Fluorescent Materials
Authors: Roselle Ngaloy | Bing Zhao | Soheil Ershadrad | Rahul Gupta | Masoumeh Davoudiniya | Lakhan Bainsla | Lars Sjöström | Md. Anamul Hoque | Alexei Kalaboukhov | Peter Svedlindh | Biplab Sanyal | Saroj P. Dash
Source: ACS Nano (article, 2024-02-08)
Field: Materials Science — Materials Chemistry

Strong In-Plane Magnetization and Spin Polarization in (Co<sub>0.15</sub>Fe<sub>0.85</sub>)<sub>5</sub>GeTe<sub>2</sub>/Graphene van der Waals Heterostructure Spin-Valve at Room Temperature Van der Waals (vdW) magnets are promising, because of their tunable magnetic properties with doping or alloy composition, where the strength of magnetic interactions, their symmetry, and magnetic anisotropy can be tuned according to the desired application. However, so far, most of the vdW magnet-based spintronic devices have been limited to cryogenic temperatures with magnetic anisotropies favoring out-of-plane or canted orientation of the magnetization. Here, we report beyond room-temperature lateral spin-valve devices with strong in-plane magnetization and spin polarization of the vdW ferromagnet (Co<sub>0.15</sub>Fe<sub>0.85</sub>)<sub>5</sub>GeTe<sub>2</sub> (CFGT) in heterostructures with graphene. Density functional theory (DFT) calculations show that the magnitude of the anisotropy depends on the Co concentration and is caused by the substitution of Co in the outermost Fe layer. Magnetization measurements reveal the above room-temperature ferromagnetism in CFGT and clear remanence at room temperature. Heterostructures consisting of CFGT nanolayers and graphene were used to experimentally realize basic building blocks for spin valve devices, such as efficient spin injection and detection. Further analysis of spin transport and Hanle spin precession measurements reveals a strong in-plane magnetization with negative spin polarization at the interface with graphene, which is supported by the calculated spin-polarized density of states of CFGT. The in-plane magnetization of CFGT at room temperature proves its usefulness in graphene lateral spin-valve devices, thus revealing its potential application in spintronic technologies. Spintronics ; Condensed matter physics ; Magnetization ; Materials science ; Spin polarization ; Ferromagnetism ; Spin valve ; Magnetic anisotropy ; Graphene ; Density functional theory ; Magnetocrystalline anisotropy ; van der Waals force ; Magnetic field ; Nanotechnology ; Physics 2D Materials and Applications ; Graphene research and applications ; Magnetic properties of thin films
Authors: Neani Tshilande | Лилиана Маммино | Mireille K. Bilonda
Source: Computation (article, 2024-04-09)
Field: Chemistry — Physical and Theoretical Chemistry

The Study of Molecules and Processes in Solution: An Overview of Questions, Approaches and Applications Many industrial processes, several natural processes involving non-living matter, and all the processes occurring within living organisms take place in solution. This means that the molecules playing active roles in the processes are present within another medium, called solvent. The solute molecules are surrounded by solvent molecules and interact with them. Understanding the nature and strength of these interactions, and the way in which they modify the properties of the solute molecules, is important for a better understanding of the chemical processes occurring in solution, including possible roles of the solvent in those processes. Computational studies can provide a wealth of information on solute–solvent interactions and their effects. Two major models have been developed to this purpose: a model viewing the solvent as a polarisable continuum surrounding the solute molecule, and a model considering a certain number of explicit solvent molecules around a solute molecule. Each of them has its advantages and challenges, and one selects the model that is more suitable for the type of information desired for the specific system under consideration. These studies are important in many areas of chemistry research, from the investigation of the processes occurring within a living organism to drug design and to the design of environmentally benign solvents meant to replace less benign ones in the chemical industry, as envisaged by the green chemistry principles. The paper presents a quick overview of the modelling approaches and an overview of concrete studies, with reference to selected crucial investigation themes. Management science ; Data science ; Computer science ; Nanotechnology ; Materials science ; Engineering Various Chemistry Research Topics ; Free Radicals and Antioxidants ; Photochemistry and Electron Transfer Studies