Values Of ΔG Research Articles

Adsorptive removal of arsenic from drinking water using KOH-modified sewage sludge-derived biochar

This paper reveals a green chemistry approach to remove arsenic (As+3) from water using potassium hydroxide (KOH) modified sewage sludge-derived biochar (SSDB-KOH). Characterisation of the morphology, particle size and composition of the SSDB-KOH pre- and post-adsorption confirmed porous and heterogenous surface favouring adsorption. At ambient temperature (20 °C), the SSDB-KOH dose of 20 g/l achieved 98 % arsenite removal at nearly neutral solution pH (8). This compared favourably with pristine SSDB, where the performance was limited to 41.6 % removal. The enhanced arsenite adsorption of SSDB-KOH was informed by several mechanisms, including ionic interactions, pore filling and metal-pi interactions. The experimental data fits closely with the Langmuir isotherm and pseudo-second-order kinetic models, revealing monolayer adsorption and the chemical interaction between adsorbents and the adsorbate. The spontaneous and endothermic nature of the process was confirmed by the negative value of ΔG and the positive value of ΔH, respectively. The performance of the biochar was evaluated for four-cycle regeneration. Finally, a cost analysis was performed to demonstrate the economic feasibility of using SSDB-KOH to remove arsenic from water.

Removal of Lead Using Novel Composite Synthesized from Rice Husk and Used Tea Leaves Extract

Untreated industrial effluents, particularly from tanneries and heavy industries, are the main source of heavy metal pollution, which poses serious environmental risks. Lead is one of the most toxic heavy metals, adversely affects human functioning and accumulates in the environment. This study presents ACUTLaqE (Activated Carbon-Used Tea Leaves Aqueous Extract) as an effective adsorbent for Pb2+ ion removal from their aqueous solution. The composite was synthesized by blending activated carbon from rice husks with a tea extract solution and characterized using SEM, XRD, and FTIR spectroscopy. Batch tests demonstrated that ACUTLaqE is highly efficient, removing about 99% of Pb2+ ions at an adsorbent dose of 2 g/L within 30 minutes. The adsorption data conformed well to the Langmuir isotherm model, suggesting a homogeneous monolayer formation on the composite surface. The qm was 38.61 mg/g, with an RL value close to 0, indicating highly favourable adsorption. Thermodynamic parameters showed negative Gibbs free energy (ΔG⁰) values, reflecting a spontaneous adsorption process. The enthalpy (ΔH⁰) and entropy (ΔS⁰) changes were 66.86 KJmol-1 and 257.12 JK-1mol-1, respectively. The adsorption mechanism involved electrostatic interactions and surface complexation with the composite's hydroxyl and carboxyl groups. These findings suggest that ACUTLaqE is a promising adsorbent material for Pb2+ and potentially other heavy metals removal from industrial effluents.

New perspective into the interaction behavior explore of Nano-berberine with alpha-lactalbumin in the presence of beta-lactoglobulin: Multi-spectroscopic and molecular dynamic investigations

The present study was focus on the interaction of alpha lactalbumin (α-LA) and Nano-berberine (Nano-Ber) in the absence and presence of beta lactoglobulin (β-LG) as binary and ternary systems by the exertion of different spectroscopic techniques, conductometry, β-galactosidase activity, and molecular simulation measurements. The outcomes of fluorescence quenching clarified the dominance of static quenching mechanism throughout the interaction of α-LA-Nano-Ber and (α-LA-β-LG) Nano-Ber complexes and also determined the KSV values to be (4.68±0.05) × 104 and (5.18±0.06) × 104 M−1, respectively. The measured thermodynamic parameters exhibited the participation of electrostatic forces in the binding interaction of α-LA and α-LA-β-LG complex with Nano-Ber. Moreover, the negative value of ΔG0 represents the spontaneous mode of this binding process in both systems. Synchronous fluorescence and resonance light scattering data demonstrated the impact of β-LG attendance on altering the interaction behavior of α-LA and Nano-Ber. The changes in the secondary structure of both proteins were affirmed by circular dichroism spectroscopy (CD) technique. According to the displayed β-galactosidase activity in the Michaelis-Menten plot of both binary and ternary systems, a greater Vmax refers to the stronger affinity of lactose and lactose hydrolysis that can be effective on the lactose intolerance regarding dairy products. Additionally, molecular dynamic simulations were employed to simulate the atomic-level interactions and explore the stability and conformational changes of protein-Nano Ber complexes over time. The results of these comprehensive biophysical investigations shed light on the binding characteristics, structural alterations, and dynamic behavior of Nano-Ber upon interaction with α-lactalbumin in the absence and presence of β-lactoglobulin as the binary and ternary systems. This study reveals the Nano-Ber role in the protein–protein interaction behavior and provides valuable insights into the potential applications of α-lactalbumin in the design of functional food formulations and drug delivery systems

The utilization of ionic liquids as sustainable and eco-friendly inhibitors for corrosion protection of carbon steel in petroleum fields

Various ionic liquid compounds are synthesized from the combination of iminodiethanol and fatty acid of butyric (IL-4) caprylic (IL-8) and capric (IL-10). The composition of such compounds was confirmed by various spectroscopic techniques and was tested as mitigators for the destruction of carbon steel in 10 % diluted oil field-produced water. The measurements of electrochemical potentiodynamic polarization, impedance spectroscopy, and gravimetry were complemented by surface investigation of some corroded carbon steel samples utilizing scanning electron microscopy-energy dispersive X-ray analysis (SEM-EDX). The data indicated that the addition of IL-4, IL-8, and IL-10 inhibits the destruction of carbon steel in the 10 % diluted oil field-produced water by lowering the corrosion current density (Iorr) and the double-layer capacitance (Cdl). Tafel polarization data confirmed that the studied compounds acted as mixed inhibitors. The values of the cathodic Tafel slope, bc, are found to be close to each other confirming that the adsorbed compounds did not alter the mechanism of hydrogen evolution. The charge transfer resistance, Rct, for the blank solution is 1501 and increased with the addition of such compounds to reach 5332 at a concentration of 500 mg/l of IL-10 with a protection efficiency of 85.83 %, at 25 ◦C. The computed -ΔG°ads values varied between −18.11 and –23.98kJ mol/1 depending on the type of inhibitor and the temperature, which confirms the suggestion of the physisorption mechanism. The negative values of ΔG°ads explain the spontaneity of the adsorption process. The lowering in Kads values with T is attributed to the escaping of some of the adsorbed inhibitor molecules leaving the carbon steel surface. Theoretical quantum computation was used to confirm the adsorption ability of various ionic liquids on the examined metal.

Theoretical insights into the radical scavenging performance of common anti-agers from both kinetic and thermodynamic perspectives

In this article, the radical scavenging performance of eight anti-agers (TMQ, ETMQ, DCD, o-MBp24, o-MBp14, p-BBp14, DNPD, and 6PPD) was benchmarked by the experimental residue rates of the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals, followed by the theoretical investigation from the perspective of both kinetic and thermodynamic factors. Kinetically, anti-agers with lower Gibbs free energy barriers (ΔG≠) presumably exhibit higher scavenging performance. Moreover, the scavenging performance is also controlled by the thermodynamic feature, that is, the small difference in Gibbs free energy between products and reactants (ΔG(R → P)) promotes the scavenging performance. Therefore, the ΔG≠×ΔG(R → P) indicator considering both kinetic and thermodynamic contributions was proposed here to comprehensively explain the difference in the scavenging performance of anti-agers. The strong positive correlation between experimental residues and ΔG≠×ΔG(R → P) values (R2 = 0.806) revealed that the ΔG≠×ΔG(R → P) indicator promises to be a reliable metric to theoretically assess the scavenging performance of anti-agers.

Precise Regulation the Multiemission Based on Soft Double Salt for Information Encryption.

Manipulation of multiemissive luminophores is meaningful for exploring luminescent materials. Herein, we report a soft double salt assembly strategy that could result in well-organized nanostructures and different luminescence based on multiple weak intermolecular interactions thanks to the existence of electrostatic attraction between the anionic and cationic platinum(II) complexes. The cationic complexes B1 and B2 can coassemble with anionic complex A, respectively, and the emission switches from monomeric and excimeric emission to the triplet metal-metal-to-ligand charge transfer (3MMLCT) along with morphology changes from 0-dimensional (0-D) nanospheres to 3-dimensional (3-D) nanostructures. It is demonstrated that an isodesmic growth mechanism is adopted during the spontaneous self-assembly process, and the relative negative ΔG values make the anionic and cationic complex molecules prefer to form aggregates based on π-π stacking, Pt···Pt interactions, and electrostatic interactions. The coassembly strategy between anionic and cationic complexes endows them with multicolor luminescent and apparent color as optical materials for advanced information encryption.

Sensing of Co2+ and Cu2+ Ions Using Dimethylamino-functionalized Poly(azomethine-1,3,4-oxadiazole)s.

The ability of OxT and OxFl azomethines to recognize metal ions in THF solutions was investigated using UV-vis absorption techniques. Various metal ions, including Cd2+, Hg2+, Co2+, Sn2+, Cu2+, Ni2+, Zn2+ and Ag+, were tested. The absorption spectra revealed two distinct π-π* transition bands in the 273-278nm and 330-346nm wavelength ranges. Additionally, OxFl displayed an absorption peak at 309nm, attributed to the fluorene group. Spectral titrations were used to study the fluorescence behavior in the presence of these metal ions. The results showed significant quenching with Co2+ and Cu2+ ions, while other metal ions had minimal effects on the fluorescence intensity. The quenching mechanism was further analyzed using the Stern-Volmer and Lehrer equations, and the binding constants ( ) were calculated using the Benesi-Hildebrand relations. The results confirm that Co2+ has a 1:2 stoichiometry and Cu2+ has a 1:1 stoichiometry, indicating the strong affinity of OxFl and OxT for these ions. The negative values of ΔG (Gibbs free energy) suggest that complex formation occurs spontaneously at room temperature.

Synthesis of novel bentonite/pectin-grafted-poly(crotonic acid-co-acrylic acid) hydrogel nanocomposite for adsorptive removal of safranin O dye from aqueous solution

ABSTRACT This novel work is devoted to the synthesis of the bentonite/pectin-grafted-poly(crotonic acid-co-acrylic acid (AA-co-CA) hydrogel nanocomposite by free-radical copolymerisation method for exploring its potential towards safranin O dye removal. The prepared nanocomposite was characterised by different techniques revealing the presence of numerous functionalities, porous nature and greater swelling % at basic pH. The pHpzc of the nanocomposite was determined to be 4. Maximum of 97.09% of safranin O dye removal take place under optimised conditions, that is, 0.03 g of bentonite dose (bentonite to net hydrogel weight ratio (1.295%), with pH of 7, nanocomposite dose of 5 g/l for 120 min. The dye concentration was 500 mg/l at the temperature of 25°C. Effect of ionic strength confirmed the greatest decrease in adsorption capacity in the presence of divalent cations. The highest R2 and the lowest error margins of the Freundlich isotherm and pseudo-second-order kinetic models make these models well fitted to the experimental data. Further, the spontaneous and exothermic nature of the process was confirmed by the negative values of ΔG and ΔH, respectively. The enhanced adsorption of safranin O dye by the prepared nanocomposite was informed by several mechanisms, including electrostatic, pore filling and H-bonding. A comparison of the adsorption capacity of the prepared nanocomposite with various other adsorbents was also studied. Stability of the prepared adsorbent was revealed from its recovery upto five cycles in different desorption media. Finally, the treatment of the adsorbent with real textile wastewater showed its removal efficiency as 95.8% highlighting its promising nature for treating large industrial wastewater.

Selective separation of lead (II) from foodstuffs and environmental samples by adsorption onto modified truffle peels with nanoparticles [TPs/TiO2(NP)] as a novel biomass

ABSTRACT This study aims to examined truffle peel powder modified with nanoparticles [TPs/TiO2(NP)] as a solid adsorbent for the removal of lead ions Pb(II) from environmental media and foodstuffs. The characterisation of TPs/TiO2(NP) was studied by a Fourier-transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and energy dispersive X-ray (EDX). Through the application of several adsorption isotherm models, the Langmuir at 25°C revealed to be most appropriate, having the highest R2 (0.961), and the maximum Pb(II) adsorption capacity was found 0.908 mg g−1. In addition, the various kinetics models were applied, and the data was well-fitted by the pseudo-second order kinetics model (R2 = 0.9997). Thermodynamic parameters indicated that the technique of adsorption had been endothermic (∆H = 30.79 J mol−1), The value of ΔG indicates the spontaneous and physical nature (- 29.26 KJ mol−1) and the positive value of ∆S indicates a moderate step of sorption of the Pb(II) complex ion associate (98.32 J). Foodstuffs (energy drinks and ice pops) and environmental samples (tap water) were successfully confirmed with a good recovery.

Efficient removal of crystal violet dye from water using zinc ferrite-polyaniline nanocomposites.

Nanomaterials are widely employed in wastewater treatment, among which nanoferrites and their composites hold significant prominence. This study adopts a green approach to synthesize zinc ferrite nanoparticles, subsequently integrating them with polyaniline (PANI) to fabricate the ZnFe2O4-PANI nanocomposite. Characterization of the prepared ZnFe2O4-PANI nanocomposite was conducted using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopic (SEM) techniques. Using Scherrer's equation, the crystallite size of the synthesized zinc ferrite nanoparticles was found to be 17.67nm. SEM micrographs of the ZnFe2O4-PANI nanocomposite revealed that in situ polymerization of ZnFe2O4 with polyaniline transforms the amorphous surface morphology of the polymer into a homogeneous nanoparticle structure. The adsorption of crystal violet (CV) dye onto the surface of the ZnFe2O4-PANI nanocomposite depends on pH, adsorbent dosage, temperature, concentration levels and duration. The Langmuir adsorption model fitted the data well, indicating adherence to a pseudo-second-order kinetic pattern. Thermodynamic values ΔG°, ΔH° and ΔS° indicated that the adsorption process occurred spontaneously. Advantages and disadvantages of the technique have also been highlighted. Mechanism of adsorption is discussed. From the obtained results, it is evident that the ZnFe2O4-PANI nanocomposite holds promise as a sorbent for the removal of dye from wastewater.

A theoretical study on the solvent effects on adsorption behavior of naproxen with PLGA nanoparticles

The objective of this research is to study the influence of naproxen (NPX) adsorption on structural, electronic, and optical features of poly (lactic-co-glycolic acid) (PLGA) in the dichloromethane (CH2Cl2), chloroform (CHCl3), and water (H2O) phases through density functional dispersion correction (DFT-D) calculations. The analyses conducted in the chloroform phase, considering binding energy and chemical reactivity parameters, indicate that NPX forms stronger hydrogen bonds with PLGA in state B (−0.60 eV) compared to states A (−0.37 eV) and C (−0.47 eV), primarily through its carboxyl (–COOH) group by using B3LYP-D/6–311 + G** level of theory. The formation of hydrogen bonds between naproxen and PLGA in the chloroform phase is most stable compared to the dichloromethane and water phases. According to time-dependent density functional theory (TDDFT) calculations, the B3LYP method predicts the maximum optical absorption in the UV region for complex B, with an optical energy of 5.41 eV and an oscillator strength of 0.781, resulting in a maximum absorption peak at 229 nm. Based on the infrared (IR) spectra analysis, we find alterations in pristine PLGA and NPX due to their interaction. The interaction between NPX and PLGA results in more negative Gibbs free energy (ΔG) values, which in turn lead to an elevation in dipole moment, enhanced solubility, and a decrease in the energy gap (Eg). As a result of NPX adsorption, the decreased energy gaps enhance the electronic and optical sensitivity of PLGA to the NPX molecule.

Ion-Exchange Resin/Carrageenan-Copper-Based Nanocomposite: Artificial Neural Network, Advanced Thermodynamic Profiling, and Anticoagulant Studies.

Carrageenan (CG) and ion exchange resins (IERs) are better metal chelators. Kappa (κ) CG and IERs were synthesized and subjected to copper ion (Cu2+) adsorption to obtain DMSCH/κ-Cu, DC20H/κ-Cu, and IRP69H/κ-Cu nanocomposites (NCs). The NCs were studied using statistical physics formalism (SPF) at 315-375 K and a multilayer perceptron with five input nodes. The percentage of Cu2+ uptake efficiency was used as an outcome variable. Via the grand canonical ensemble, SPF gives models for both monolayer and multilayer sorption layers. For in vitro anticoagulant activity (ACA), the activated partial thromboplastin time were calculated using 100 μL of rabbit plasma incubated at 37 °C. After 2 min, 100 L of 0.025 M CaCl2 was added, and the clotting time was recorded for each group (n = 6). The results demonstrated that the key covariables for the adsorption process were pH and concentration. The results of artificial neural network models were comparable with the experimental findings. The error rates varied between 4.3 and 1.0%. The prediction analysis results ranged from 43.6 to 89.2. The ΔG and ΔS values for IRP69H/κ-Cu obtained were -18.91 and -16.32 and 26.21 and 22.74 kJ/mol for the temperatures 315 and 345 K, respectively. Adsorbate species were perpendicular to the adsorbent surfaces, notwithstanding the apparent importance of macro- and micropore volumes. These adsorbents typically fluctuate with temperature changes and contain one or more layers of sorption. Negative and positive sorption energies correspond to endothermic and exothermic processes. The biosorption energy (E1 and E2) values in this experiment have a value of less than 23 kJ mol-1. Complex SPF models' energy distributions validate surface properties and interactions with adsorbates. At a concentration of 100 μg/mL, DC20H/κ-Cu2+ exhibited an ACA of only 8 s. These NCs demonstrated better greater ACA with the order DC20H/κ < DMSCH/κ < IRP69H/κ. More research is needed to rule out the chemical processes behind the ACA of CG/IER-Cu NCs.

Synthesis and Biological Evaluation of 3-(2-Benzoyl-4-chlorophenyl)-4H-spiro [indole-3,2-[1,3]thiazolidine]-2,4(1H)- dione Derivatives for Anti-tubercular and Antimicrobial Activities

Objectives: To synthesize a new scaff fold of 3'-(2-Benzoyl-4-chlorophenyl)-4'H-spiro [indole-3,2'-[1,3] thiazolidine]-2,4'(1H)-dione derivatives and to assess the compounds for anti-tubercular and antimicrobial activities. Methods : A new series of 3'-(2-Benzoyl-4-chlorophenyl)-4'H-spiro [indole-3,2'- [1,3] thiazolidine]-2,4'(1H)-dione derivatives were prepared by synthesizing schiff’s bases followed by condensing schiff base with 2-mercaptopropanoic acid in the presence of zinc chloride. Synthesized compounds were characterized by IR, NMR and Mass spectral data. Their antimicrobial, antitubercular and also docking simulations were evaluated. Findings : Compound 3c (floro substituent) showed potent activity against Mycobacterium tuberculosis H37Rv with MIC value of 3.125 µg/ml when compared with standard Isoniazid. Compound 3c, 3d and 3f displayed better antimicrobial activity against used bacterial and fungal species with MIC range of 3-20µg/ml comparable to standard drugs ciprofloxacin and ketoconazole respectively. In silico studies revealed that compound 3c, 3f and 3d had a better binding affinity with M. tuberculosis enoyl-CoA hydratase EchA6 with ΔG values of -9.6kcal/mol, -9.4kcal/mol, and -8.6kcal/mol respectively comparable to isoniazid of -5.4kcal/mol. Compound 3c, 3f and 3d also displayed good binding affinity with DNA gyrase and lanosterol methylase. Novelty : Introducing benzoyl moiety to the thiazolidine ring potentiates the antitubercular and antimicrobial activity of spiro indole derivatives. Keywords: AntiTB, Antimicrobial, Molecular Docking, Spiro indole, Thiazolidine

INHIBISI ENZIM α-GLUKOSIDASE OLEH SENYAWA FLAVONOID DAUN KELOR (Moringa oleifera) IN SILICO DAN IN VITRO

Moringa leaves flavonoid have potential to inhibit α-glucosidase but they have low bioavailability, so they aremade in nanoparticles. It is also not known which specific flavonoid compounds from Moringa leaves have thepotential to inhibit α-glucosidase. This research aimed to determine the inhibition potential of α-glucosidase bythe moringa leaves flavonoid in silico through molecular docking and determine the inhibitory activity of α-glucosidase by moringa leaves flavonoid in extracts and nanoparticles in vitro. Moringa leaves flavonoid havepotential to be a competitive inhibiton of α-glucosidase with the highest to lowest inhibitory potential arecryptochlorogenic acid, quercetin-3-O-beta-D-glucopyranoside, quercetin-3-glucoside, kaempferol-3-O-a-ramnoside, kaempferol-3-O-glucoside, epicathechins, catechins, quercetin, kaempferol, glucomoringinisothiocyanate. Cryptochlorogenic acid has the best potential with ΔG and Ki values -8.5 kcal/mol and 0.5788μM. Inhibition α-glucosidase moringa leaves flavonoid in extract and nanoparticles respectively are classified asinactive (IC 50 = 5.84x10 3 ppm) and active (IC 50 = 1.59x10 1 ppm) in vitro, so nanoparticles can increase theinhibitory activity.

Biosorption of Methyl Orange Dye in Single, Binary and Ternary System onto Gingerbread Plum Seed Shell Activated Carbon

The research investigated the potential of gingerbread plum seed shell activated to function as a biosorbent for eliminating methyl orange (MO) dye from water in various dye combinations, including single, binary, and ternary systems alongside methylene blue (MB) and Congo red (CR) dyes. The characteristics of the adsorbent were analyzed through techniques like Scanning Electron Microscopy, Fourier Transform Infrared spectroscopy, and pH point of zero charges. Batch adsorption tests were conducted to examine the adsorption processes' equilibrium behaviors, thermodynamics, and kinetics. The collected data were subjected to different isotherm and kinetics equations. The pseudo-second-order kinetics model provided the best fit for all the sorption systems, irrespective of composition differences, with higher rate constants observed for binary MO+MB= 0.031 g/mg/min system and lower for binary MO+CR= 0.028 g/mg/min and ternary MO+MB+CR= 0.029 g/mg/min systems compared to the single system MO= 0.030 g/mg/min. The maximum monolayer capacity of the adsorbent for methyl orange demonstrated synergistic interaction with the presence of methylene blue and antagonistic interaction with the presence of Congo red dye. The findings indicated that the adsorption processes varied based on the system's composition; they were all spontaneous (with Δ𝐺 values ranging from -1.146 to -10.415 kJ/mol) and exothermic (with Δ𝐻 values between -17.94 and -54.63 kJ/mol). Additionally, randomness decreased, as reflected by Δ𝑆 values of -054.43 and -382.62 J/K for the entire process.

Strategic regulation of nitrogen-containing intermediates for enhanced nitrate reduction over Co3O4/SiC catalyst having multiple active centers

Regulating the intermediates involved in the electrocatalytic nitrate reduction reaction (NO3RR) is crucial for the enhancement of reaction efficiency. However, it remains a great challenge to regulate the reaction intermediates through active site manipulation on the surface of the catalyst. Here, a family of n%-Co3O4/SiC (n = 5, 8, 12, 20) catalysts with a delicate percentage of Co2+ and Co3+ were prepared for NO3RR. We found that Co3+ primarily acts as the active site for NO3− reduction to NO2−, while Co2+ is responsible for the conversion of NO2− to NH3. Moreover, the conversion of these intermediates over the active sites is autonomous and separately controllable. Both processes synergistically accomplish the reduction of nitrate ions to synthesize ammonia. Combining the experimental studies and density functional theory (DFT) calculations, it is discovered the pathway (*NHO→*NHOH→*NH2OH→*NH2→*NH3) is more favorable due to the lower ΔG value (0.25 eV) for the rate-limiting step (*NO→*NHO). The NH3 yield rate of 8%-Co3O4/SiC reached 1.08 mmol/(cm2 h) with a Faradaic efficiency of 96.4% at −0.89 V versus the reversible hydrogen electrode (RHE), surpassing those of most reported non-noble NO3RR catalysts. This strategy not only provides an efficient catalyst for NO3RR but also serves as an illustrative model for the regulation of multi-step reaction intermediates through the design of distinct active sites, thereby presenting a new approach to enhance the efficiency of intricate reactions.

Identification of Potential Therapeutics of Mentha Essential Oil Content as Antibacterial MDR Agents against AcrAB-TolC Multidrug Efflux Pump from Escherichia coli: An In Silico Exploration.

Multidrug-resistant bacterial pathogens, such as E. coli, represent a major human health threat. Due to the critical need to overcome this dilemma, since the drug efflux pump has a vital function in the evolution of antimicrobial resistance in bacteria, we have investigated the potential of Mentha essential oil major constituents (1-19) as antimicrobial agents via their ability to inhibit pathogenic DNA gyrase and, in addition, their potential inhibition of the E. coli AcrB-TolC efflux pump, a potential target to inhibit MDR pathogens. The ligand docking approach was conducted to analyze the binding interactions of Mentha EO constituents with the target receptors. The obtained results proved their antimicrobial activity through the inhibition of DNA gyrase (1kzn) with binding affinity ΔG values between -4.94 and -6.49 kcal/mol. Moreover, Mentha EO constituents demonstrated their activity against MDR E. coli by their ability to inhibit AcrB-TolC (4dx7) with ΔG values ranging between -4.69 and -6.39 kcal/mol. The antimicrobial and MDR activity of Mentha EOs was supported via hydrogen bonding and hydrophobic interactions with the key amino acid residues at the binding site of the active pocket of the targeted receptors.

Fast and efficient extraction of phenol from aqueous phase using deep eutectic solvents: Experimental and density functional theory investigation for interactions studies

Phenol is carcinogenic and toxic to human beings and therefore it is necessary to remove this toxic pollutant from water. Hydrophobic deep eutectic solvents (DESs) were prepared using trioctylamine (TOA) as hydrogen bond acceptor (HBA) and 2-hydroxybenzoic acid and 4-dodecylbenzenesulfonic acid as hydrogen bond donors (HBDs) for extraction of phenol from aqueous media. Fourier transformer infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA) were performed for functional group and thermal stability determination, respectively. Phenol extraction efficiency of DESs was studied under different experimental parameters, such as initial pH of phenol solution (2–10), contact time (1–15 min), mixing ratio of volume of DESs to aqueous media (VDES:Vaq.) (1:10–1:50 mL), initial concentration of phenol (1000–5000 ppm) and temperature (25 °C–55 °C). More than 97 % extraction efficiency of DES for phenol was achieved using contact time of 5 min, initial phenol concentration of 2500 ppm, VDES:Vaq in a ratio of 1:10 mL, and temperature of 25 °C. The values of ΔG° calculated for phenol extraction at various temperatures have negative values, confirming that the phenol movement from water phase to DESs phase is spontaneous in nature. Density functional theory (DFT) simulations were conducted to study the interaction of DESs with water and phenol. In addition, DFT was used to determine the interaction energy of DESs with water and phenol. The considerably higher interaction energies (−20.4 and 18.2 kcal/mol) obtained with both DESs for phenol over water emphasize the selective separation efficiency of DESs for phenol. The experimental results confirmed that these synthesised DESs can effectively extract phenol from the aqueous phase to the organic phase.

Study on the Optimization, Extraction Kinetics and Thermodynamics of the Ultrasound-Assisted Enzymatic Extraction of Tremella fuciformis Polysaccharides.

In this study, Tremella fuciformis polysaccharides (TFPs) were extracted by ultrasound-assisted enzymatic extraction (UAE) at different extraction parameters in order to explore the potential of ultrasound in intensifying the extraction yield. The effects of experimental conditions on the extraction yields were optimized using response surface methodology, with the optimal ultrasonic power of 700 W, temperature of 45 °C and time of 50 min. The kinetic analysis revealed that UAE significantly promoted the dissolution, diffusion and migration with the maximum yield of 26.39%, which was enhanced by 40.45% and 156.96% compared with individual ultrasonic extraction (UE) and enzymatic extraction (EE). According to the modified Fick's second law of diffusion, the extraction process of TFPs illustrated a good linear correlation (R2 ≥ 0.9), and the rate constant gradually elevated as the temperature increased from 25 to 45 °C, while the presence of ultrasound exerted a vital role in extracting TFPs. Regarding to the thermodynamic results, the positive values of ΔH and ΔG demonstrated that UAE, UE and EE were endothermic and unspontaneous processes. This study provides a theoretical basis for polysaccharide extraction processing.

Kinetics and thermodynamics in microwave-assisted transesterification of palm oil utilizing sulphonated bio-graphene catalysts for biodiesel production

Enhanced reaction performance is what has piqued interest in using graphene-based catalysts in producing biodiesel. However, in-depth analyses were lacking from a kinetic and thermodynamic standpoint. This means that a well-designed experiment is necessary to determine the effect that the graphene catalysts have on the reaction rates and yields. This work addresses the kinetic and thermodynamic aspects of heterogeneously catalyzed transesterification using sulphonated biomass-derived graphene catalysts, i.e., bGO-SO3H and brGO-SO3H. It was accomplished using the pseudo-first order mechanism and the Eyring-Polanyi equation, with all data fitting satisfactorily in both models at the ideal reaction temperature of 353.15 K, resulting in R2 values of 0.9784 (bGO-SO3H) and 0.9884 (brGO-SO3H). The calculated activation energy (Ea) was determined to be 44.45 and 51.73 kJ mol-1 for bGO- and brGO-SO3H, respectively. Additionally, the Gibbs free energy (ΔG) values were determined at −38.09 and −31.81 kJ mol−1 for bGO- and brGO-SO3H, respectively. Meanwhile, the values for ΔH and ΔS were obtained as 41.69 kJ mol−1 and 225.93 J mol−1 K−1, respectively, and 48.96 kJ mol−1 and 228.72 J mol−1 K−1, respectively. These collective outcomes collectively signify the endothermic nature of the reaction and their spontaneity, particularly under elevated temperature conditions.