Mechanisms of isomerization and hydration reactions of typical β-diketone at the air-droplet interface

Acetylacetone (AcAc) is a typical class of β-diketones with broad industrial applications due to the property of the keto-enol isomers, but its isomerization and chemical reactions at the air-droplet interface are still unclear. Hence, using combined molecular dynamics and quantum chemistry methods, the heterogeneous chemistry of AcAc at the air-droplet interface was investigated, including the attraction of AcAc isomers by the droplets, the distribution of isomers at the air-droplet interface, and the hydration reactions of isomers at the air-droplet interface. The results reveal that the preferential orientation of two AcAc isomers (keto- and enol-AcAc) to accumulate and accommodate at the acidic air-droplet interface. The isomerization of two AcAc isomers at the acidic air-droplet interface is more favorable than that at the neutral air-droplet interface because the "water bridge" structure is destroyed by H3O+, especially for the isomerization from keto-AcAc to enol-AcAc. At the acidic air-droplet interface, the carbonyl or hydroxyl O-atoms of two AcAc isomers display an energetical preference to hydration. Keto-diol is the dominant products to accumulate at the air-droplet interface, and excessive keto-diol can enter the droplet interior to engage in the oligomerization. The photooxidation reaction of AcAc will increase the acidity of the air-droplet interface, which indirectly facilitate the uptake and formation of more keto-diol. Our results provide an insight into the heterogeneous chemistry of β-diketones and their influence on the environment.

Electrochemical and computational insights into the utilization of 2, 2- dithio bisbenzothiazole as a sustainable corrosion inhibitor for mild steel in low pH medium

Industries today place a high premium on environmentally friendly supplies that may effectively inhibit metal dissolution at a reasonable cost. Hence, in this paper, we assessed the corrosion inhibition effectiveness of the Thiazole derivative namely, 2, 2-Dithio Bisbenzothiazole (DBBT) against mild steel (MS) corrosion in 1 M HCl. Several experimental approaches, including gravimetric analysis, potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), and surface exploration using scanning electron/atomic force microscopy (SEM/AFM) and contact angle (CA), were utilized to conduct the measurements. In 1 M HCl corrosive medium at 298 K in the subsistence of 800 ppm of DBBT, this experiment indicated DBBT as an environment-friendly and sustainable corrosion inhibitor (CI) for MS, demonstrating an inhibition efficiency (IE %) of 97.71%. To deliver a deeper knowledge of the mechanism behind inhibitive behavior, the calculated thermodynamic and activation characteristics were applied. The calculated Gibbs free energy values indicated that the CI interacted physically and chemically with the MS surface, validating physio-chemical adsorption. The findings of the EIS research revealed that an upsurge in the doses of the CI is escorted by an upsurge in polarization resistance (Rp) from (88.05 → 504.04) Ωcm2, and a diminution in double layer capacitance (Cdl) from (97.46 → 46.33) μFcm-2 at (50 → 800) ppm respectively, affirming the inhibitive potential of DBBT. Additionally, the greatest displacement in Ecorr value being 76.13 mV < 85 mV, indicating that DBBT act as a mixed-form CI. To study the further impacts of DBBT on the inhibition capabilities of the compound under investigation, density functional theory (DFT) and molecular dynamics (MD) simulation were employed. Chemical and electrochemical approaches are in agreement with the computational analysis indicating DBBT is the most efficient CI.

Anti-reflection effect of high refractive index polyurethane with different light trapping structures on solar cells

The textured surfaces to reduce light reflectivity by using acid-alkali chemical etching and SiNx films are generally necessary for commercial crystalline silicon solar cells. However, this etching process requires a large amount of environmentally harmful acid-alkali solution and has limited options for texture and size. To overcome these disadvantages, a new anti-reflection strategy is proposed in this study, which is using soft nanoimprint lithography to prepare the textured structures on the outside of the SiNx films. The polyurethane with a high refractive index of 1.64 is selected as the texture material, and different templates are selected to prepare it into different light trapping structures, including positive-inverted pyramids, inverted lace cones, and positive-inverted moth-eye nanostructures allowing for easy customization of the textured structures. The finite element simulation and experiments demonstrate that these light trapping structures have a wide spectrum anti-reflection performance in visible and near-infrared bands. With the back surface of the commercial passivated emitter rear contact (PERC) bi-facial solar cells as the imprint substrates, some light trapping structures can reduce the surface weighted average light reflectivity (Rw) at the band of 300-1200 nm from 18.31% to less than 10% and the optimal structures can reduce Rw to 8.71%. This anti-reflection strategy can also be applied to thin-film solar cells and crystalline silicon solar cells of other structures, such as HIT, Topcon, Perovskite/c-Si tandem, and so forth, which shows great development potential.

Yolk-like non-stoichiometric nickel sulfide-based Janus hydrogel photothermal film for enhanced solar-driven water evaporation and multi-media purification

Solar-driven interface water evaporation is a promising strategy for desalination and wastewater treatment. However, it remains a huge challenge to simultaneously achieve a high light-to-heat conversion efficiency (η) and multi-media evaporation applications. In this study, a highly efficient Janus hydrogel photothermal film was developed using yolk-like non-stoichiometric nickel sulfide (NiS_2-x) microspheres and agar hydrogel. The NiS_2-x immobilized in the agar hydrogel has full-spectrum absorption characteristics at 200-2500 nm, which can perform efficient light-to-heat conversion and regulate water transport channels. Additionally, the pure agar in the bottom can transport water effectively and avoid heat loss. By the pouring method, the Janus hydrogel film can be easily prepared into various shapes; hence, it can be adjusted depending on the environment in which it is used. The optimized Janus hydrogel film (Janus hydrogel-1) possessed good hydrophilicity and showed an excellent solar evaporation rate of 1.45 kg m^-2h^-1, and a high η of 97% under one-sun irradiation. Theoretical simulation results showed that the outstanding water evaporation performance of Janus hydrogel-1 was mainly due to its relatively free water transport channels. Janus hydrogel-1 can be used for water evaporation applications in various media, including seawater, heavy metal ion/organic wastewater, and domestic sewage. Our work highlights the great potential of Janus hydrogel-1 for realizing a highly effective solar energy-driven interface water evaporation and multi-media purification.

Patterned separator membranes with pillar surface microstructures for improved battery performance

In order to improve battery performance by tuning battery separator membranes, this work reports on porous poly(vinylidene fluoride-co-trifluoroethylene) - P(VDF-TrFE)- membranes with surface pillar microstructures. Separators with tailored pillar diameter, height and bulk thickness were fabricated by template patterning and computer simulations, allowing to evaluate the effect of the pillar microstructure characteristics on battery performance. It is shown that the different pillar microstructures of the separators affect the uptake value (150-325%), ionic conductivity value (0.8-1.6 mS·cm^-1) and discharge capacity of the lithium ion batteries (LIB) when compared with the separator without pillars. The experimental charge-discharge behavior demonstrates that the pillar parameters affect battery performance and the best microstructure leading to 80 mAh·g^-1 at 2C. Battery performance can be thus optimized by adjusting pillar diameter, height and bulk thickness of the separators keeping its volume constant, as demonstrated also by the simulation results. The parameter with most influence in battery performance is the bulk thickness of the separator, allowing to obtain a maximum discharge capacity value of 117.8 mAh·g^-1 at 90C for a thickness of 0.01 mm. Thus, this work shows that the optimization of the pillar microstructure of the separator membranes allows increasing the capacity towards a new generation of high-performance LIBs.

Theoretical electronic circular dichroism investigations of chiral amino acids and development of separation and identification methods independent of standards

Through an appropriate computational protocol and environmental simulation, a satisfactory fit was observed for the theoretical electronic circular dichroism (ECD) spectra of 19 chiral amino acids (AAs), which correspondeds to the forms of the AAs in aqueous solution. Methods for enantioseparation of these chiral AAs by capillary electrophoresis (CE) and high-performance liquid chromatography (HPLC) were developed. Combining ECD with chromatographic separation methods, enantiomers were identified and quantified independent of a single enantiomer standard.

High efficient adsorption and storage of iodine on S, N co-doped graphene aerogel

High efficient adsorption of radioiodine in nuclear waste has attracted extensive attentions all over the world. In this work, we fabricated sulfur and nitrogen co-doped graphene aerogels (SN-GA) through one-step hydrothermal method, and investigated its iodine adsorption behavior including adsorption kinetics and isotherms in water. Our results reveal that SN-GA exhibits a 3D porous architecture with thiophene-S, oxidized-S, pyridine-N, pyrrole-N and graphite-N co-doped into the sp² carbon frameworks. The adsorption experiment showed SN-GA has a maximum iodine adsorption capacity of 999 mg g^-1 determined by Langmuir isotherm, and the adsorption process could be better described by the pseudo-second-order model.

Macroscopic, theoretical simulation and spectroscopic investigation on the immobilization mechanisms of Ni(II) at cryptomelane/water interfaces

In the present study, the macroscopic sorption behaviors and microscopic immobilization mechanisms of Ni(II) at cryptomelane/water interfaces were explored using the combination of batch sorption technique, desorption procedure, theoretical simulation, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and extended X-ray absorption fine structure (EXAFS) analyses. The good simulation of the pseudo-second-order model on the sorption kinetics data suggests a driving force of chemical sorption rather than mass transport or physical interaction. The sorption trends and uptake mechanisms are obviously related to the solution pH, with cation exchange or outer-sphere surface complexation at an acidic pH of 4.0, inner-sphere surface complexation in both the edge-shared (ES) and double corner-shared (DCS) modes at a neutral pH of 7.0, and precipitation of α-Ni(OH)₂(s) phase at a highly alkaline pH of 10.0. The gradual increase of Ni(II) sorption amount with solution temperature rising from 293 K to 333 K is consistent with the increased ratio of the weak DCS configuration. The research findings herein can help us better understand the migration and transformation trends of Ni(II) in the manganese mineral-riched aquatic environment.

Synthesis, in silico and in vivo blood brain barrier permeability of ginkgolide B cinnamate

Ginkgolide B, one of the important components of Ginkgo biloba extracts, has been revealed to exhibit great potential in therapy of cerebrovascular diseases. However the lack of permeability greatly limited it from further clinical application. Based on the prediction model for blood brain barrier (BBB) permeation, herein a potential brain-targeting analog ginkgolide B cinnamate (GBC) was successfully synthesized and characterized. After intravenous administration of GBC or GB, liquid chromatography tandem mass spectrometry (LC-MS/MS) was conducted to determine the analog in rat plasma and brain. The results showed that GBC had a significant increase in BBB permeability. A significant 1.61-times increase in half-life was observed for GBC and the drug targeting index (DTI) value was calculated to be 9.91. The experiment results matched well with the predicted one, which revealed that BBB permeability prediction model combined with in vivo study could be used as a quick, feasible and efficient tool for brain-targeting drug design.

Graphene-based liquid-gated field effect transistor for biosensing: Theory and experiments

We present an experimental and theoretical characterization for reduced Graphene-Oxide (rGO) based FETs used for biosensing applications. The presented approach shows a complete result analysis and theoretically predictable electrical properties. The formulation was tested for the analysis of the device performance in the liquid gate mode of operation with variation of the ionic strength and pH-values of the electrolytes in contact with the FET. The dependence on the Debye length was confirmed experimentally and theoretically, utilizing the Debye length as a working parameter and thus defining the limits of applicability for the presented rGO-FETs. Furthermore, the FETs were tested for the sensing of biomolecules (bovine serum albumin (BSA) as reference) binding to gate-immobilized anti-BSA antibodies and analyzed using the Langmuir binding theory for the description of the equilibrium surface coverage as a function of the bulk (analyte) concentration. The obtained binding coefficients for BSA are found to be same as in results from literature, hence confirming the applicability of the devices. The FETs used in the experiments were fabricated using wet-chemically synthesized graphene, displaying high electron and hole mobility (µ) and provide the strong sensitivity also for low potential changes (by change of pH, ion concentration, or molecule adsorption). The binding coefficient for BSA-anti-BSA interaction shows a behavior corresponding to the Langmuir adsorption theory with a Limit of Detection (LOD) in the picomolar concentration range. The presented approach shows high reproducibility and sensitivity and a good agreement of the experimental results with the calculated data.