Forrestcolon1879

In this paper, we present a detailed evaluation of changes in the oil residue in soil following a spill using weathering indices obtained from analytical instruments such as UV, IR, GC, and 1H NMR, and chemometrics based on the time of spill in the Niger Delta region of Nigeria. UV, IR and 1H NMR spectra of eight (8) oil residue samples were analyzed. learn more The PCA of the UV and IR spectrometric index showed that the first two PCs accounted for 87 and 71% of the variance of the index, respectively. The detailed results suggested that the absorption ratios A 225/256 and A 248/278 from UV were good estimators for petroleum of different weathering profiles and the presence of different types of di- and poly-aromatics, nitrogen, sulphur, and oxygen (NSO) containing compounds. Similarly, sulphoxide, aromatic, and carbonyl index obtained from IR would be more valuable in evaluating changes in oil residue over time. An 84% PC obtained for NMR indicators described for weathered crude oil was the best at explaining structural changes compared to the region defined for fresh heavy crude oil. These models showed good predictive ability for the crude-oil residue composition and could be used to provide a rapid assessment of compositional differences in crude-oil residue following a spill.[This corrects the article DOI 10.1039/D2RA00574C.].A sulfonated porous polymer monolith (PPM-SO3H) has been prepared via the polymerisation of styrene (St) and divinyl benzene (DVB) with organic microspheres as pore-forming agents, followed by sulfonation with concentrated sulfuric acid. It was characterized by acid-base titration in order to determine its acid density, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, mercury intrusion porosimetry (MIP) and thermogravimetric analysis (TG). The PPM-SO3H showed an acid density of 1.89 mmol g-1 and pore cavities with an average diameter of 870 nm. The catalytic activity of PPM-SO3H in practical biodiesel synthesis from waste fatty acids was investigated and the main reaction parameters were optimized through orthogonal experiment. The best reaction conditions obtained for the optimization of methanol to oil ratio, catalyst concentration, reaction temperature and reaction time were 1  1, 20%, 80 °C and 8 h, respectively. PPM-SO3H showed excellent catalytic activity. In biodiesel synthesis, the esterification rate of PPM-SO3H is 96.9%, which is much higher than that of commercial poly(sodium-p-styrenesulfonate) (esterification rate 29.0%). The PPM-SO3H can be reused several times without significant loss of catalytic activity; the esterification rate was still 90.8% after 6 cycles. The pore size of this porous polymer monolith can be controlled. The dimension and shape of this porous polymer monolith were also adjustable by choosing a suitable polymerisation container.Nuclear Magnetic Resonance (NMR) spectroscopy and Magnetic Resonance Imaging (MRI) are analytical and diagnostic tools that are essential for a very broad field of applications, ranging from chemical analytics, to non-destructive testing of materials and the investigation of molecular dynamics, to in vivo medical diagnostics and drug research. One of the major challenges in their application to many problems is the inherent low sensitivity of magnetic resonance, which results from the small energy-differences of the nuclear spin-states. At thermal equilibrium at room temperature the normalized population difference of the spin-states, called the Boltzmann polarization, is only on the order of 10-5. Parahydrogen induced polarization (PHIP) is an efficient and cost-effective hyperpolarization method, which has widespread applications in Chemistry, Physics, Biochemistry, Biophysics, and Medical Imaging. PHIP creates its signal-enhancements by means of a reversible (SABRE) or irreversible (classic PHIP) chemical reaction between the parahydrogen, a catalyst, and a substrate. Here, we first give a short overview about parahydrogen-based hyperpolarization techniques and then review the current literature on method developments and applications of various flavors of the PHIP experiment.A facile two-step strategy to prepare flexible graphene electrodes has been developed for supercapacitors using thermal reduction of graphene oxide (GO) and thermally reduced graphene oxide (TRGO) composite films. The tunable porous structure of the GO/TRGO film provided channels to release the high pressure generated by CO2 gas. The graphene electrode obtained from reduced-GO/TRGO (1  1 in mass ratio) film showed great flexibility and high film density (0.52 g cm-3). Using the EMI-BF4 electrolyte with a working voltage of 3.7 V, the as-fabricated free-standing reduced-GO/TRGO (1  1) film achieved a great gravimetric capacitance of 180 F g-1 (delivering a gravimetric energy density of 85.6 W h kg-1), a volumetric capacitance of 94 F cm-3 (delivering a volumetric energy density of 44.7 W h L-1), and a 92% retention after 10 000 charge/discharge cycles. In addition, the solid state flexible supercapacitor with the free-standing reduced-GO/TRGO (1  1) film as the electrodes and the EMI-BF4/poly (vinylidene fluoride hexafluopropylene) (PVDF-HFP) gel as the electrolyte also demonstrated a high gravimetric capacitance of 146 F g-1 with excellent mechanical flexibility, bending stability, and electrochemical stability. The strategy developed in this study provides great potentials for the synthesis of flexible graphene electrodes for supercapacitors.A new epoxy ergostane sterol, named versisterol, was isolated from Aspergillus versicolor, an endophytic fungus from Avicennia marina. The structure of the isolated compound was deduced by means of one- and two-dimensional NMR and high-resolution mass spectrometry. The absolute stereochemistry was elucidated by NOESY analysis, and experimental and calculated time-dependent density functional theory (TD-DFT) circular dichroism spectroscopy. Versisterol inhibited 3CL protease (3CLpro) with an IC50 value of 2.168 ± 0.09 μM. Binding affinities and molecular interactions of versisterol towards 3CLpro were scrutinized and compared to lopinavir with the help of the combination of docking computations and molecular dynamics (MD) simulation. In silico calculations demonstrated a comparable binding affinity of versisterol with a docking score of -9.4 kcal mol-1, and MM-GBSA binding energy over 200 ns MD simulation of -29.1 kcal mol-1, with respect to lopinavir (-9.8 and -32.2 kcal mol-1, respectively). These findings suggested that versisterol can be an auspicious prototype for developing new 3CLpro drug candidates against COVID-19.Shear thickening fluid (STF) is investigated to strength soft armor; however, its impact resistance still does not meet practical needs. In this work, a small amount of hydroxylated fullerene (C60) was mixed with STF to improve the thickening ratio. First, furfuryl alcohol (FA) was grafted onto C60 through a Diels-Alder (D-A) reaction to improve the dispersity of C60 in the STF. Sheath-core composite fibers (polyketone (PK) as the sheath and STF as the core) were then fabricated by coaxial electrospinning. Finally, composite fibers containing STF and C60 were wrapped on the surface of aramid yarns to fabricate a core-spun yarn. Under impact, these core-spun yarns manifested the characteristics of aramid fibers and the thickening advantages of the STF, solving problems of the hygroscopicity, migration, and leakage of STF. In addition, the content of STF was also greatly increased. The spike punching resistance of the core-spun yarn fabric is about 2.8 times that of the aramid fabric (AF) under the same area density. Impact-resistant core-spun yarn fabrics could provide a new direction for the development of soft armor.Formaldehyde (HCHO) oxidation to improve indoor air quality has attracted extensive attention. Designing efficient catalysts for HCHO removal at room temperature still remains challenging. Herein, we report a novel strategy to boost HCHO oxidation by the synergistic effect of Pt nanoparticles and C3N4. The pyridine nitrogen of C3N4 can create Lewis base sites, which function in adsorbing and activating O2 molecules. As the preparation temperature increased, the pyridine nitrogen content increased on the C3N4 surface, leading to a more significant synergistic effect. The mechanism study by in situ DRIFTS indicated that the adsorbed O2 molecules were activated by Pt/C3N4. As a result, the Pt/C3N4-650 has the most outstanding performance for HCHO oxidation at room temperature. HCHO can be completely eliminated with a concentration of 80 ppm at room temperature at a GHSV of 50 000 ml g-1 h-1. This study will provide a new perspective to design efficient HCHO oxidation catalysts.Metal sulfides are gaining prominence as conversion anode materials for lithium/sodium ion batteries due to their higher specific capacities but suffers from low stability and reversibility issues. In this work, the electrochemical properties of CuS anode material has been successfully enhanced by its composite formation using graphitic carbon nitride (g-C3N4). The CuS nanoparticles are distributed evenly in the exfoliated g-C3N4 matrix rendering higher electronic conductivity and space for volume alterations during the repeated discharge/charge cycles. The 0.8CuS0.2g-C3N4 composite when used as an anode for lithium ion coin cell exhibits a reversible capacity of 478.4 mA h g-1 at a current rate of 2.0 A g-1 after a run of 1000 cycles which is better than that reported for CuS composites with any other carbon-based matrix. The performance is equally impressive when 0.8CuS0.2g-C3N4 composite is used as an anode in a sodium ion coin cell and a reversible capacity of 408 mA h g-1 is obtained at a current rate of 2.0 A g-1 after a run of 800 cycles. A sodium ion full cell with NVP cathode and 0.8CuS0.2g-C3N4 composite anode has been fabricated and cycled for 100 runs at a current rate of 0.1 A g-1. It can be inferred that the g-C3N4 matrix improves the ion transfer properties, alleviates the volume alteration happening in the anode during the discharge/charge process and also helps in preventing the leaching of polysulfides generated during the electrochemical process.Reprocessing of spent nuclear fuel aims at improving resource efficiency and reducing its radiotoxicity and heat production in the long term. The necessary separation of certain metal ions from the spent fuel solutions can be achieved using different solvent extraction processes. For the scenario of the EURO-GANEX process, the use of the new, modified diglycolamide 2,2'-oxybis(N,N-didecylpropanamide) (mTDDGA) was recently proposed to simplify the current solvent composition and reduce extraction of fission products. Before further developing the process based on this new ligand, its stability under ionizing radiation conditions needs to be studied. For this reason, gamma irradiation experiments were conducted followed by analyses with high performance liquid chromatography coupled to a mass spectrometer (HPLC-MS). The determined degradation rate of mTDDGA was found to be lower than that of the reference molecule N,N,N',N'-tetra-n-octyl-diglycolamide (TODGA). Many identified degradation compounds of both molecules are analogues showing the same bond breaking, although also unreported de-methylation, double/triple de-alkylation and n-dodecane addition products were observed.