Physical Chemistry Research
Volume:12 Issue: 2, Spring 2024

This research presents a novel approach for the production of Rice Bran fatty acid ethyl esters as biodiesel by utilizing Rice Bran Fatty Acid Distillate (FAD) and Ethanol from Sugar factories. The use of Aspergillus Oryzae based Liquid Lipase (Eversa® Transform 2.0 FG) as a catalyst, along with the recycling of the separated emulsion layer, showcases a unique methodology. Additionally, the incorporation of ethanol as a solvent and the implementation of a top-up dosage of lipase in consecutive experiments demonstrate an innovative strategy for enzyme recycling, achieving high conversion rates. The surprising by-product of non-contaminated water, easily reusable in other applications, further distinguishes this research, contributing to a more sustainable and cost-effective biodiesel production process.

In this work, the ZnS/montmorillonite/graphitic carbon nitride (ZnS/MMT/g-C3N4) as a novel composite was synthesized through simple strategy. The addition of MMT showed positive impact for increasing the specific surface area of g-C3N4, and the photocatalytic activity of g-C3N4 was achieved higher by using ZnS as a semiconductor. Several techniques were applied to evidence the formation of the as-synthesized composite such as X-ray powder diffraction, Fourier transform infrared spectroscopy, Field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, Ultraviolet-visible light diffuse reflectance spectroscopy, Brunauer-Emmett-Teller analysis, high-resolution transmission electron microscopy, and photoluminescence spectroscopy. The adsorption and photocatalytic activities of ZnS/MMT/g-C3N4 were evaluated for the removal of Rhodamine B (Rh. B). Response surface methodology was used to study the important parameters and their interaction in the adsorption process. The pH, adsorbent dose, and dye concentration were shown the effect on the adsorption process, and the adsorption process was corresponded to Freundlich isotherm and pseudo-second-order kinetic models. The photocatalytic activity of ZnS/MMT/g-C3N4 was studied under several condition, which the best results were obtained 93% yield under ultra violet irradiation. This study presents a novel adsorbent and photocatalyst composite with high yield for the removal of Rh. B dye.

Given the pandemic of COVID-19, the new generation of coronavirus noted SARS-CoV-2 still remains a global health threat to this day, the absence of effective and reliable treatments against its severe acute respiratory syndromes implies day after day forced and relentless research in order to delimit the degree of danger of this virus. In this work, we performed in silico studies on some Eugenol derivatives in order to suggest promising molecules that could be anti- SARS-CoV-2 drugs, in a first step, a molecular docking study was conducted on a set of 59 compounds derived from Eugenol as inhibitors of the main protease SARS-CoV-2, based on the results, six compounds were distinguished by the best energy scores, have been chosen to show the binding mode of eugenol derivative inhibitors, subsequently, we proceeded to the prediction of pharmacokinetics and ADMET properties on six compounds that showed good affinity towards the main protease, only one compound, according to the selection criteria of Lipinski and Veber, showed pharmacological properties suitable for human administration. In addition, the binding stability of the selected compound with our base protein was evaluated by performing molecular dynamics simulations which consequently showed good stability with SARS-CoV-2 Mpro under aqueous conditions.

In this study, quantum chemical computational calculations were performed on the electronic structure of pyrogallol carboxaldehydes, specifically pyrogallol-4-carboxaldehyde (P4C) and pyrogallol-5-carboxaldehyde (P5C), using the DFT / B3LYP / 6-311++G(d,p) basis set. A comprehensive analysis of their structural, chemical, biological, and various electronic features has been investigated to gain deeper insights into pyrogallol carboxaldehydes. Moreover, Mulliken population and molecular electrostatic potential surface (MESP) have been conducted to gain a comprehensive understanding of the bonding characteristics and reactive sites of the pyrogallol carboxaldehydes. The pharmacokinetic properties, including absorption, distribution, metabolism, and excretion (ADME), have been assessed to predict the toxicity of pyrogallol carboxaldehydes. Furthermore, in silico molecular docking was employed to determine the biological significance of pyrogallol carboxaldehydes as potential anti-tumour agents by targeting oncogenic proteins such as Kristen rat sarcoma viral oncogene (K-RAS), Harvey rat sarcoma viral oncogene (H-RASGTP), and H-RASGDP with a binding energy of -5.46, -5.38, -5.52 kcal/mol and -5.53, -5.64, -5.60 kcal/mol for P4C and P5C respectively.

In this study, the inhibition effect of Alyssum floribundum Boiss. & Balansa on the corrosion of mild steel was examined using electrochemical measurements in a 1M H2SO4 solution. The experimental results demonstrated that the extract of Alyssum floribundum exhibited significant inhibitory performance. According to the potentiodynamic polarization measurements, the highest inhibition efficiency was 98% when using a 1M H2SO4 solution containing 20 g/l of the plant extract. To determine the activation energy and temperature dependence of the corrosion inhibition process, polarization measurements were conducted at different temperatures ranging from 27°C to 60°C. The inhibition efficiency increased with an increasing concentration of the inhibitor, and the activation energies were found to be 33.56 kJ·mol-1 in a 1M H2SO4 solution and 96.98 kJ·mol-1 in the presence of the inhibitor (1M H2SO4 + 20g/ml). It was observed that the Langmuir adsorption isotherm was suitable for the adsorption of A. floribundum leaf extract on the surface of mild steel in an acidic solution.

Cancer is the second most lethal disease worldwide after cardiovascular disease. Discovering and developing new drugs and repurposing existing drugs to curb this disease have gathered interest from researchers globally. In this work, computer-aided approaches via density functional theory (DFT), molecular docking, and pharmacokinetics were adopted for the evaluation of anti-breast cancer activity of 2-({4-[(1H-Benzimidazol-2-yl)sulfanyl]phenyl}methylidene)hydrazine-1-carbothioamide and its modified derivatives. In the result, the BMHCd showed the lowest bang gap energy, highest enthalpy change, and highest Gibb’s free energy indicating the most reactive among the compounds. Also, molecular docking showed that all the compounds have stable interactions and higher binding energy, with BMHCf showing the highest (-8.469 kcal/mol). Furthermore, all the compounds satisfy the Lipinski rule of five and are therefore, good therapeutic candidates for the treatment of human cancer.

Natural fiber is typically derived from plants that exhibit low density, light weight, and abundant availability, along with the added advantage of being biodegradable. The Cardia Dichotoma plant's branches serve as a prominent source of natural cellulose fiber, offering a vast quantity for extraction. However, despite its hydrophilic nature, natural fiber exhibits poor compatibility with both fiber and matrix during the mixing process. To enhance its adhesive properties, the fiber undergoes a series of treatments, including Alkalization, Benzoylation, and Acetylation. In this research, the influence of alkali (untreated, 5%, 10%, and 15% NaOH) was investigated over morphology, functional groups, physical and mechanical properties of fiber obtained from Cardia Dichotoma. SEM indicated bigger pore size, reduced thickness and rough surface with etched striations in alkali-treated samples. FTIR peaks inferred that the use of alkali receded hemicellulose, cellulose and lignin. Tensile Force & Elongation at intervals showed that the mechanical properties of the increasing amount of Alkali reduced the mechanical properties of the fiber by 5 percentages. Conclusively, 5% NaOH was found to be the optimum ratio that effectively removed hemicellulose, cellulose and lignin, however, higher percentage decreased tensile strength and elongation at break of the respective fiber.

Exposure to pigment waste effluents is important because a little amount of dyes in poisonous water is visible and has ruinous effects on humans and the ecosystem, and has been presented as a serious environmental obstacle. Lately, the outreach of technologies that can diminish contaminants to the permissible surface has been thought-out. Of all the offered techniques, biosorption is one of the most popular techniques for eliminating contaminants from wastewater. Adsorption is an effective method to treat chromatic effluents and a fruitful route to protect the ecosystem. Diverse categories of economic and productive adsorbents that are compatible with the ecosystem are utilized to omit dyes. Amongst the economic adsorbents, the utilization of industrial wastes is so usual. The preponderances of these compounds' utilization are low cost, optimal yield, facile availability, excellent recyclability, and high adsorption capacity. Based on the considered the previous study, FA, iron-containing waste, blast furnace dust industrial- by product provided for favourable Percentage removal efficiency (%) and adsorption capacity to remove dyes under optimal conditions, proving their potential and unique characteristics for removal dyes. This study focuses on the examination of Hazards and various types of dyes, as well as an investigation into the process of biosorption.

ZnO nanoparticles are prepared with lime juice by the green, facile solution combustion method and act as a photoanode for DSSC fabrication. The structural and morphological features of ZnO nanoparticles are examined via XRD, FTIR, UV-Vis, DLS, and SEM. The XRD detects defect-free wurtzite hexagonal structure with a crystallite size ~16.28 nm. SEM image reveals a spherical morphology with a uniform spreading of ZnO nanoparticles (~45 nm). UV–Vis analysis exhibited high absorbance in the UV (~200 to 400 nm) and vital transparency in visible region (~400 to 600 nm). The band gap (3.07 eV) is estimated and is blue-shift and associated with the bulk of the ZnO (3.37 eV) because of the impact of quantum confinement. The doctor blade approach is adopted to prepare photoanode. ZnO-based DSSC is constructed, wherein Pt is the counter electrode, with an iodine redox couple as the electrolyte and N719 dye utilized as a sensitizer. Photovoltaic performance (Voc, Jsc, η, and FF) of the fabricated FTO/ZnO-N719 dye/iodide redox coupled electrolyte/Pt/FTO device is studied. The maximum (PCE) η 3.7447% is achieved with a maximum Voc ~0.734 mV, Jsc ~9.768 mA/cm2, and FF ~0.5223. Hence, synthesized ZnO nanoparticles may be an excellent photoanode material for DSSC application.

This article explores the insights provided by infrared (IR) spectroscopy into the optical properties and surface morphology of polyethylene (PE) polypropylene (PP), and polyvinyl chloride (PVC) films. Notably, IR spectroscopy can identify absorption lines attributed to various functional groups in addition to those associated with lower-density linear polyethylene. The specific characteristics of IR spectra for linear low density polyethylene are influenced by polymer processing conditions, branching, and monomer content. Moreover, the IR spectrum of PVC offers valuable information about its molecular structure and composition. Comparatively, polypropylene (PP) films exhibit higher absolute light transmission in the ultraviolet and visible spectrum when contrasted with films based on PE and PVC. The utilization of atomic force microscopy (AFM) and IR spectroscopy reveals that heat-induced decomposition and subsequent cooling do not impact the surface roughness or thickness of the films, confirming the retention of structural and electrophysical attributes.

In this study, an innovative method is used in the synthesis of Pd-doped CeO2 nanoparticles through co-precipitation, with a focus on an extensive characterization of their structural, optical, and magnetic properties. Powder X-ray diffraction (XRD) and scanning electron microscopy (SEM) confirm a cubic structure via XRD and spherical morphology through SEM, respectively. Energy-dispersive X-ray spectroscopy (EDAX) further corroborated the presence of Pd, Ce, and O constituents in these nanoparticles. An intriguing finding revolves around the optical band gap, as Pd concentration increased, the optical band gap diminished from 2.92 eV to 2.25 eV, spanning from Pd0.00 Ce100O2 to Pd5.0 Ce95.0O2. Chemical bonding analysis via X-ray Photoelectron Spectroscopy (XPS) confirmed the presence of Ce, O, and Pd elements with distinct binding energies: Ce 3d at 850–920 eV, O1s at 530 eV, and Pd 3d at 360 eV. Additionally, Raman spectra displayed a prominent peak at 464.01 cm-1, indicating a slight deviation from the bulk CeO2's typical Raman active mode at 459 cm-1, hinting at potential phonon confinement effects due to reduced particle size. Besides, magnetic studies unveiled enhanced properties in 5% Pd-doped CeO2, transitioning from diamagnetic to paramagnetic behaviour.

In this present research, reduced graphene oxide (RGO) and hexagonal boron nitride (h-BN) nanoparticles decorated RGO sheets for a solid-state hydrogen storage medium are synthesized and characterized. The nanocomposite of RGO/h-BN was prepared using the ultrasonic-assisted liquid-phase exfoliation approach and the modified Hummer's method for graphene oxide (GO) synthesis. Using micro-Raman spectroscopy, XRD, SEM, CHNS elemental analysis, and TGA, the produced RGO and RGO/h-BN nanocomposite were evaluated. XRD and micro-Raman validate the RGO and the RGO decorated with h-BN nanoparticles. SEM analysis authorizes the h-BN nanoparticles to be decorated on the surface of the RGO sheet. Using a hydrogenation system akin to Sievert's, the hydrogen adsorption behavior of RGO and RGO/h-BN nanocomposite was investigated. With a maximal hydrogen absorption of 2.1 wt% at 100°C, RGO/h-BN nanocomposite performs better than bare RGO. In the temperature ranges of 109 to 140° and 115 to 149°, the RGO and RGO/h-BN nanocomposites released 100% stored hydrogen. The corresponding binding energy of RGO and RGO/h-BN nanocomposites were 0.31 and 0.32 eV, which is adequate for fuel cell applications. The RGO/h-BN nanocomposite is therefore anticipated to have a promising future in hydrogen storage situations of fuel cell applications.

In this study, nanoscale zero-valent iron supported onto Zeolite Clinoptilolite (NZVI/Zeolite) was synthesized from a facile method as an adsorbent for removing Cu (II) from aqueous solutions. Field Emission Scanning Electron Micrographs (FESEM) showed no aggregation, and dot mapping revealed the uniform dispersion of iron onto the surface of the zeolite. The surface area of synthesized NZVI/Zeolite was obtained at about 132.14 m2/g by BET analysis. Also, the isotherm adsorption of Cu (II) onto NZVI/Zeolite was best fitted with the Temkin isotherm (R2=0.894) and maximum adsorption capacity (qm) of Cu (II) onto NZVI/Zeolite was 61.72 mg/g. The maximum removal of Cu (II) by NZVI/Zeolite was about 99.98% at pH=8, the dosage of adsorbent = 0.1 mg/L, Cu (II) concentration = 60 mg/L, and time = 30 min. The reusability of nanocomposite after five consecutive cycles showed 12.72% reduction in the removal of Cu (II). These results suggest that NZVI/Zeolite has excellent potential for the removal of Cu (II) from aqueous solutions.

Different compounds are created when chlorine molecules and vinyl radicals react. Over the lowest doublet potential energy surface, a potential mechanism for this reaction has been put forth at the CBS-QB3 and CCSD(T)/CBSB3 levels of theory. According to theoretical kinetics studies, the dominant product in this system is CH2Cl-CHCl. One deep potential well and 10 distinct channels make up the doublet surface for the reaction in the title. The Single-well multichannel RRKM method along with steady-state approximation for the corresponding intermediate (RRKM-SSA) have been used to estimate the rate constants for the formation of the most likely products that pass through the energized pre-reaction adduct over the temperature and pressure ranges of 300 to 3000 K and 5 to 10,000 Torr. The pressure dependence of various channels is also examined.

In this study, three alternative techniques were used to recycle expanded polystyrene waste (WPS). Sulfonated polystyrene (PSS)-based materials (PSS-01, PSS-02, and PSS-03) were produced and employed as efficient and reasonably priced adsorbents. The findings demonstrated that the clearance efficiency of expanded polystyrene increased from 13.6% for pH = 3 to 21% at pH = 9. The removal capacity for sulfonated polystyrenes, which varied from 60% to 85% and 98% for PSS-01, PSS-02, and PSS-03, respectively, did not alter over the pH range. Furthermore, the removal effectiveness of the sulfonated polystyrenes was unaffected by increasing the starting dye concentration. However, for a methylene blue (MB) concentration of 200 mg. L-1, the removal capacity employing PSS-02 significantly decreased and fell to less than 62%. The elimination rate of the dye by PSS-03 at the ideal contact duration of 15 min was more incredible than 98.2% at the ideal amount of 20 mg. Undoubtedly, the results showed that MB adsorption corresponded to the Langmuir isotherm for WPS and PSS-02 and the Freundlich isotherm for PSS-01 and PSS-03, and adsorption kinetic models for the three copolymers produced pseudo-second order. PSS-03's adsorption capability increased because of its hydrophilic sites and higher adsorbent surface area.

In this work, N-vinyl imidazole (NVI) and glycidyl methacrylate (GMA) were combined to create Poly(NVI-GMA). The synthesis of this novel cationic copolymer was initiated using high-temperature, ultraviolet (UV), and microwave radiation. The cationic level of Poly(NVI-GMA) was optimized during the copolymerization process. The ideal synthesis conditions included a 2% initiator concentration, equal proportions of NVI and GMA (50% (v/v) each), a polymerization duration of 4 minutes, and an acidic pH reaction media. UV-visible, FTIR, and 1H-NMR techniques were employed to examine the structure of the copolymer. To investigate the flocculation performance of the highly cationic Poly(NVI-GMA) in purifying water with high turbidity, several analyses, including Fourier transform infrared (FTIR), X-ray diffraction (XRD), and thermogravimetric (TGA) analyses, were conducted to study and summarize the flocculation mechanism. Experimental simulations utilizing maghnite as a coagulant yielded a transmittance of 96.9% in the supernatant with a concentration of 6 mg/L, a brief stirring duration of 20 minutes, an acidic pH, and a stirring speed of 200 rpm

This work focuses on the liquid membrane based extractive removal of arsenic from water. The entire work has been divided into two parts. The Part 1 presents the experimental studies and mathematical modelling. The reaction mechanism of the transport of arsenic from one aqueous phase to the other via thin liquid membrane have been explored. The experimental studies have been conducted in both two phase (only extraction) and three phase (extraction and recovery) mode. Various process parameters were varied and their corresponding extraction and recovery results have been recorded for further analysis. The crucial process parameters were identified. Mass transfer coefficients, flux, phase resistances and permeability are computed via mathematical model. The extraction equilibrium constant determined from the distribution coefficient through mathematical modelling elucidates As(V) species to be favourable for extraction into organic phase, having a value of 8.2 mol/L. Further, it is found that all the species of arsenic form complex in the organic phase with aliquat 336 in the stoichiometric ratio of 1:1.

The combustion technique was used to successfully prepare new Li4Zn(PO4)2:Eu3+ orange-red phosphors. A detailed description of the crystal phase, size distribution, luminescence characteristics, and decay curves was provided. The P21(4) space group contributes to the monoclinic structure of the Li4Zn(PO4)2:Eu3+ phosphors. The existence of pure phases of the produced phosphors was confirmed by X-ray diffraction analysis. The intense orange-red emission light that the Li4Zn(PO4)2:Eu3+ phosphors produce at 593 nm is attributable to the 5D07F1 transitions. The placement of Eu3+ ions at various site symmetries is supported by the variation in the intensity of the electric and magnetic dipole transition. Li4Zn(PO4)2:xEu3+ was shown to perform best at a concentration of 0.1 mol%, which displays great color purity. All results indicate that the Li4Zn(PO4)2:xEu3+ phosphors have potential applications in W-LEDs.

Before being used in a variety of sectors, steel is often cleaned using acidic solutions. The steel corrosion rises as a result of this treatment, necessitating the inclusion of inhibitors in the cleaning bath. Due to this, it is constantly crucial to provide new, effective corrosion inhibitors. Rivaroxaban was investigated in the current study as a mild steel corrosion inhibitor in a 1.0 M HCl solution. At 25, 30, 40, and 50 ˚C temperatures and 1, 10, 20, 30, and 40 µM concentrations of inhibitor, corrosion experiments were conducted using potentiodynamic polarisation and electrochemical impedance spectroscopy (EIS). Steel sheets' surfaces were analyzed using SEM images in both the absence and presence of the inhibitor. At an ideal concentration of 40 µM, Rivaroxaban demonstrated inhibition efficiency greater than 92%, which was reduced with an increase in temperature and time of immersion in the acidic solution. Charge transfer resistance in the presence of Rivaroxaban after 144h decreased from 1470 to 231 Ω cm2.

This paper is a continuation of the work presented in Part 1 of this series. The aim of this Part 2 is to find optimal operating condition of the process through two comparative approaches, viz. statistical approach and machine learning based model. Three important aspects of the statistical analysis, viz. descriptive, correlational and inferential statistical analyses are performed in comprehensive manner. Associated tests such as Shapiro-Wilk test and Kolmogorov-Smirnov test are conducted to check for normality. The homogeneity of variances of the dependent variable with respect to the independent variable are checked through Levene’s test. The correlational analysis are studied using Spearmann’s test and Pearson’s correlational analysis along with standard ANOVA and/or MANOVA. Based on the main effects from the test of between-subjects obtained for the variables, post hoc (Tukey HSD) analyses are computed to understand the effect of individual and combined independent variables on the dependent variables. Artificial Neural Network has been adopted in machine learning model along with Genetic Algorithm based optimization tool to compare their performances with the obtained experimental and statistical data. The data points have been divided to train, test and validate the ANN based on maximum extraction\% and recovery\% with minimum mean squared error.