Physical Chemistry Research
Volume:10 Issue: 3, Summer 2022

Biochar is an adsorbent material widely used to remove pollutants from industrial discharges. This research focuses on the adsorption capacity of Biochar, obtained by thermal decomposition of Argan shells, to remove methylene blue from aqueous solutions. The influence of some parameters such as carbonization time and temperature on the burn-off and adsorption capacities of this material was studied. A temperature of carbonization of 900 °C and a carbonization time of 2 hours are considered as the optimum conditions for the preparation of this adsorbent. The burn-off, methylene blue adsorption amount, and iodine number of the prepared activated carbon under the optimal conditions were 84.6 %, 19.9 mg g-1 and 431.8 mg g-1, respectively. The powder obtained was characterized by performing the following analyses : pHpzc, SEM, FT-IR, DRX, and TGA-DTG. It was then tested for its ability to remediate methylene blue in water by varying the carbon dosage, contact time, initial concentration and pH. The adsorption kinetics was consistent with the pseudo-second-order model. To analyze the experimental data, Langmuir, Freundlich, and Temkin models were studied. The equilibrium data are in agreement with the Langmuir model with a monolayer maximum adsorption capacity of 31 mg g-1.

ABSTRACTChloroxylon Swietenia tree bark was being used as an eco-friendly bio-adsorbent in our research work. This research work has investigated the adsorption efficiency of nickel by using a batch adsorption technique. Chloroxylon swietenia is commonly known as East Indian satinwood, which is popularly known as Porasu in Tamil. Chloroxylon swietenia activated carbon (CSAC) has been prepared from Chloroxylon swietenia tree bark as an adsorbent. Effective experimental parameters like carbon dosage, effect of pH parameter, contact time, pseudo-first order kinetic model, and Elovich model have been employed for the removal of nickel from an aqueous solution. The equilibrium data was calculated using adsorption isotherm models such as Langmuir and Freundlich. The percentage removal of nickel was calculated by thermodynamic parameters. The research studies proved that the removal of nickel by CSAC was endothermic as well as spontaneous in nature. The adsorption of nickel on CSAC has been determined by using the Fourier transform infrared spectroscopy technique.

In this work, a simple method was employed to prepare MnO2 nanoparticles and characterized by various techniques, including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and atomic force microscope (AFM). The diffraction peak of MnO2 nanoparticles matched well with standard data. The AFM and SEM images prove the growth of MnO2 nanorods from the MnO2 nano spherical shape. An ultra-low dielectric constant PVA (P)-pentaerythritol (Ery) /MnO2 nanocomposite films are fabricated by evaporating casting method. The dielectric constant and losses of P-Ery/MnO2 films were measured between 10 kHz and 1 MHz using LCR, as the content of MnO2 increased, the dielectric constant decreased from 1.6 to 1.3 and the loss tangent of P-Ery at 400 KHz was very low and increase with increase of MnO2 content. Thermogravimetric analysis (TGA) and Scanning electron microscope (SEM) were used to investigate the thermal stability and surface analysis of films.

Our present study provides a detailed knowledge on structure and spectroscopic properties of 2-ethyl-2-phenyl malonamide. The optimized geometrical parameters, vibrational wavenumbers and electronic spectra have been theoretically done by Density Functional Theory (DFT) employed with B3LYP 6-311++G(d,p) basis set. The experimental vibrational wavenumbers were characterized by Fourier transform infrared (FT-IR) and Fourier Transform Raman (FT-Raman) spectroscopy were recorded in the region 4000-400 cm-1. The 1H and 13C nuclear magnetic resonance (NMR) chemical shifts have been calculated using Gauge Independent Atomic Orbital (GIAO) method. The UV-Vis spectrum was recorded in gas phase and compared with theoretical spectrum. Other molecular properties such as Natural Bond Orbital (NBO) analysis was also carried out to determine stability and charge delocalization, molecular electrostatic potential surface was generated to study the electrophilic and nucleophilic sites of the title compound, Finally the calculated theoretical findings show good agreement with observed spectra to confirm the structure of 2-ethyl-2-phenyl malonamide.

3D-QSAR has indeed established itself as a very useful component in the design of compounds with biological potential. The use of this tool will therefore make it possible to more easily target the modulations to be carried out in order to improve the inhibitory capacity of the series studied.Statistical analyses of CoMFA and CoMSIA molecular interaction field descriptors and the model validation methods they generate are presented and applied to the three-dimensional quantitative structure-activity relationships study of a series of 32 wild-type HCT 116 p53 inhibitor styrylquinolines. The selected CoMFA and CoMSIA models were generated by the partial least squares "PLS" method and all had very good internal prediction and cross-validation coefficient values Q² of 0.601 and 0.6 respectively. In view of the results obtained by the contour maps of the developed models as well as the results of molecular docking, new analogues of styrylquinoline were designed.The study of the physicochemical, pharmacokinetic and potential toxicity properties shows that the two newly predicted compounds T1 and T3 presented a better ADMET profile, in particular a good gastrointestinal absorption, compared to the most active compound taken from the literature,

The density, refractive index, and electrical conductivity of binary and ternary mixtures containing sulfolane (2) + 1, 3-butanediol (1) + lithium perchlorate or sodium perchlorate or ammonium perchlorate were measured at temperatures between 293.15-313.15 K. From the density data, the excess molar volume〖 V〗_m^E, the partial molar volume ( V) ̅_(m,i), the excess partial molar volume V ̅_(m,i)^Ewere obtained. The excess molar volumes were correlated using the Redlich-Kister equation to estimate the respected coefficients and standard deviations. Using the Reis equation, the excess refractive index n_D^E was obtained and fitted by the Redlich-Kister equation. Moreover, the values of the specific electrical conductivity have been fitted by polynomial equation to calculate the adjustable parameters constants. The sign and magnitude of excess quantities have been discussed in terms of the nature of molecular interactions between the components. The impacts of the electrolyte and solvation effects on the volumetric, optical properties and conductivity behavior were also addressed.

Speeds of sound and density of the mixtureswere measured in the binaries of 2-methoxy ethanol (2-ME) with selected amines (diethylamine (DEA), triethylamine (TEA), tert-butylamine (TBA)) at 298.15, 303.15, 308.15 and 313.15 K at 0.1MPa. We used the measured data to calculatethe excess speeds of sound, , excess molar isentropic compressibility, .The computed quantities were fitted to the Redlich-Kister polynomial equation to derive the coefficients and estimate the standard error values. The excess speed of sound values vary from 18.41 ms-1 to 45.06 ms-1 and in case of excess molar compressibility, the observed range is -1.0270 x 1014 m5N-1mol-1 to -0.4070 x 1014 m5N-1mol-1 among all the systems considered. The excess partial molar volume and isentropic compressibility of the constituents at infinite dilution were also calculated. The consolidation of all the results and information drawn from them indicate that there exist strong interactions between the selected alcohol and the molecules of aliphatic amines.

Thymidine and thymidine-mimicking derivatives were found promising against microorganisms which may inhibit the growth of microorganisms providing effective therapies for several diseases. In this present study, it has been investigated the antimicrobial activities of thymidine and some of its designed derivatives by employing quantum chemical calculations. The antimicrobial tests demonstrated that the compounds 3, 4, and 14 were the most active against Pseudomonas aeruginosa, Salmonella abony, and Staphylococcus aureus strains, with the calculated MIC values ranging from 0.32 ± 0.01 to 1.25 ± 0.03 mg ml-1 and MBC values ranging from 0.32±0.01 to 2.5±0.06 mg ml-1. These derivatives exhibited much stronger biochemical activities than the standard antibacterial drugs. SAR study including in vitro and in silico analysis revealed that the lauroyl and myristoyl in combination with ribose sugar were found to be the most potential activates. PASS and quantum calculations respectively revealed excellent antimicrobial and thermodynamic properties of the designed thymidine derivatives. A molecular docking study has been performed against SARS-CoV main protease protein to investigate their binding energies and binding modes and observed that, designed derivatives exhibited improved binding affinities. In addition, the ADMET studies predicted the pharmacokinetic properties with lower acute oral toxicity i.e, noncarcinogenic of all compounds.

In current study, ternary phase equilibria of (water + n-butyric acid + 2-methylcyclohexanol) were considered. Experimental tie-line data were measured at T = 298.2, 308.5 and 318.2 K and 102.1 kPa. Type I LLE behavior was observed for the studied mixtures. Karl-Fischer and acid-base titrations were applied to analyze separated phases. The Hand and Othmer-Tobias equations were used to test the validity of obtained tie-line data. Regression coefficients of both equations were bigger than 0.99. Calculated separation factors (14.6 to 32.6) and distribution coefficients (1.5 to 4.8) proved that the studied solvent is very efficient for extraction of n-butyric acid from water. Thermodynamic modeling was performed by NRTL equation and root mean square deviations (3.54 to 4.11 %) were calculated to investigate the quality of modeling.

Deep eutectic solvents (DESs) and ionic liquids have been considered organic solvents and applied in numerous chemical procedures. DESs usually are produced by combining 2 or 3 organic components. DES can be formed in a mixture by combining hydrogen bond donors like urea, polyols, and carboxylic acids with hydrogen bond acceptors. In the present study, deep eutectic solvents as a green solvent -minimized extraction method known as Headspace-solvent microextraction was established.

Deep eutectic solvents hydrodistillation single drop microextraction (DES-HS-SDME) was presented for extracting essential oils compounds through DESs as extraction solvents prepared via combining choline chloride and p-Chlorophenol. They were used to extract volatile compounds from Satureja hortensis L. leaves. To avoid the time-consuming and traditional hydrodistillation, the volatile components in Satureja hortensis L.’s aerial parts were analyzed through a simple distillation with headspace single-drop microextraction along with gas chromatography. According to the experimental findings, DESs-HS–SDME is a rapid, low-cost, simple, and reliable technique to determine volatile fractions in Satureja hortensis L.

The electrostatic potential (V(r)), the average local ionization energy (I(r)), the relative hardness (ηrel), the electron affinity (EA), the ionization potential (IP), the electronegativity (χ), the hardness (η) and the electrophilicity (ω) were tested as theoretical descriptors of the reported in-vitro antiviral activities against SARS-CoV-2 for seven different compounds with the same set of controlled variables: chloroquine, favipiravir, nafamostat, nitazoxanide, penciclovir, remdesivir, rivabirin, in order to obtain information about the electronic nature of the hosting sites in the virus. Results indicate that the hardness of the studied drugs correlates moderately well with the biological activity, which gives some insights to infer in terms of the HSAB principle of Pearson, that the electrostatic interactions must predominate in the virus hosting sites and that these areas have low polarizability. A multiple correlation analysis was performed and the correlation improves when the conceptual hardness (η), Vmin and the molecular volume are considered, which suggests that the interaction of the molecules with the preferred hard hosting sites should be negatively affected by the volume of the selected drug and that Vmin contributes to the correlation.

Excess thermodynamic properties such as viscosity deviation (ln ∆ƞ), excess isentropic compressibility (KsE), excess molar volume (VmE), excess intermolecular free length (LfE), excess free volume (VfE), excess acoustic impedance (ZE) and excess internal pressure (ΠiE) were evaluated from the experimentally measured values of density (ρ), ultrasonic velocity (u) and viscosity (ƞ) for the binary mixtures of acetonitrile (AN) with dimethyl sulfoxide (DMSO) and with N, N-dimethylacetamide (DMA) as a function of mole fraction at temperatures- 298 K, 308 K, 318 K and 328 K. The excess values were further fitted to Redlich-Kister polynomial equation to ascertain the fitting parameters and standard deviations. The variations of excess parameters with composition and with temperature were further discussed with regard to the nature and extent of molecular interactions among the dissimilar component molecules of the investigated solvent systems. Overall positive deviation in ZE values and negative deviations in the values of LfE, VfE and KsE over the entire solvent composition range suggested the existence of strong molecular interactions between unlike molecules of the components. AN-DMA solvent system was found to exhibit a deviation more towards a stronger interaction mode as compared to AN-DMSO solvent system.