Free Entropy Research Articles

Synthesis of Ga3+ doped lithium manganese ion sieve for Li+ extraction and its adsorption thermodynamic behavior

ABSTRACT Spinel-type lithium ion sieves exhibit many advantages. We report a gallium ion-doped precursor LiGa0.1Mn1.9O4 prepared by co-precipitation and hydrothermal method. The optimal synthetic parameters were determined by the orthogonal design experiments. The precursor was then transformed into the corresponding ion sieve HGa0.1Mn1.9O4 by pickling. The dissolution loss of Mn3+ for HGMO (4.65%) is less than that of the pristine ion sieve without Ga3+ doping (6.59%), which proves that the doped Ga3+ inhibits the dissolution loss effect. The equilibrium adsorption capacity Q e of HGMO is 25.30 mg∙g−1 and the adsorption curve of HGMO for Li+ fits well with the pseudo-second-order kinetic model, indicating that the adsorption process is chemical adsorption. The adsorption isotherm conforms to the Langmuir model, and the adsorption process is monolayer adsorption. By the analysis of the adsorption enthalpy change (∆H), Gibbs free energy (∆G) and entropy (∆S) change of HGMO at different temperatures, the adsorption process of HGMO for Li+ was confirmed as endothermic and spontaneous.

Kinetic Modeling, Thermodynamic Approach and Molecular Dynamics Simulation of Thermal Inactivation of Lipases from Burkholderia cepacia and Rhizomucor miehei.

The behavior against temperature and thermal stability of enzymes is a topic of importance for industrial biocatalysis. This study focuses on the kinetics and thermodynamics of the thermal inactivation of Lipase PS from B. cepacia and Palatase from R. miehei. Thermal inactivation was investigated using eight inactivation models at a temperature range of 40–70 °C. Kinetic modeling showed that the first-order model and Weibull distribution were the best equations to describe the residual activity of Lipase PS and Palatase, respectively. The results obtained from the kinetic parameters, decimal reduction time (D and tR), and temperature required (z and z’) indicated a higher thermal stability of Lipase PS compared to Palatase. The activation energy values (Ea) also indicated that higher energy was required to denature bacterial (34.8 kJ mol−1) than fungal (23.3 kJ mol−1) lipase. The thermodynamic inactivation parameters, Gibbs free energy (ΔG#), entropy (ΔS#), and enthalpy (ΔH#) were also determined. The results showed a ΔG# for Palatase (86.0–92.1 kJ mol−1) lower than for Lipase PS (98.6–104.9 kJ mol−1), and a negative entropic and positive enthalpic contribution for both lipases. A comparative molecular dynamics simulation and structural analysis at 40 °C and 70 °C were also performed.

Effect of nonfactorizable background geometry on the thermodynamics of galaxy clusters

In this paper, we study the effect of nonfactorizable background geometry on the thermodynamics of the clustering of galaxies. A canonical partition function is derived for the gravitating system of galaxies treated as point particles contained in cells of appropriate dimensions. Various thermodynamic equations of state, like Helmholtz free energy and entropy, among others, are also obtained. We also estimate the effect of the corrected Newton’s law on the distribution function of galaxies. Remarkably, the effect of the modified Newton’s law is seen only in the clustering parameter while the standard structure of the equations is preserved. A comparison of the modified clustering parameter [Formula: see text] with that of the original clustering parameter is made to visualize the effect of the correction on the time scale of clustering. The possibility of system symmetry breaking is also analyzed by investigating the behavior of the specific heat with increasing system temperature.

Efficient simultaneous removal of tetracycline and cefazolin from aqueous solution using a novel adsorbent based on zero-valent iron nanoparticles supported by montmorillonite and graphene oxide: isotherms, kinetic, and thermodynamic studies

ABSTRACT In recent years, antibiotics in aqueous solutions have drawn extensive attention due to their harmful effect on human health and the environment. In this study, efficient and rapid adsorption of two antibiotics, including tetracycline (TC) and cefazolin (CFZ) on synthesised montmorillonite (Mt)/nano zero-valent iron (nZVI)/graphene oxide (GO) from aqueous solutions was studied. The prepared adsorbent was characterised by scanning electron microscope (SEM), energy dispersive X-Ray (EDX), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), and vibrating sample magnetometer (VSM). One-factor-at-a-time (OFAT) method was used to optimise the experimental factors. The maximum removal percentage was achieved at pH of 7, an adsorbent dosage of 0.4 g, contact time of 7 min = TC and 10 min = CFZ, initial concentration of 5 mg L−1, and a temperature of 298 K. The evaluation of isotherm models indicated that the Langmuir isotherm with a coefficient of determination (R2) value of 0.9992 for both antibiotics was selected as the best fitting model to describe the adsorption process. The maximum adsorption capacities (qmax) of Mt-nZVI-GO were obtained at 43.24 mg g−1 for TC and 20.36 mg g−1 for CFZ. Furthermore, the pseudo-second-order (PSO) kinetic model fitted well for TC (R2 = 0.9937) and CFZ (R2 = 0.9997). Thermodynamic parameters, i.e. adsorption Gibbs free energy (ΔG0), standard enthalpy (ΔH0), and standard entropy (ΔS0) were estimated. It was found that the adsorption had spontaneous and exothermic in nature. The results revealed that Mt-nZVI-GO could be used as a simple, efficient, and eco-friendly adsorbent for the simultaneous removal of contaminants in aqueous media.

Pyrrolidinium bromide deep eutectic solvents in separation of molecular solutes: Solvent selection for separating industrial mixtures

The separation of molecular solutes utilizing deep eutectic solvents for industrial processes is essential and important for the purpose of green solvent applications. Deep eutectic solvents (DES) based on 1.000:2.002 M ratio of [1-ethyl-1-methylpyrrolidinium bromide + triethylene glycol] and 1.000:2.001 M ratio of [1-ethyl-1-methylpyrrolidinium bromide + diethylene glycol] were used to evaluate their potential in separation of industrial mixtures. The pre-screening of the prepared DESs was based on the activity coefficients at infinite dilution measurements using gas liquid chromatography at different temperatures and at atmospheric pressure. The experimental data was conducted at temperature, T = (313.15–343.15) K. The intermolecular interactions occurring between the solvent and solute were discussed. These were further discussed by computing the excess thermodynamic functions at infinite dilution (enthalpies, ΔH1E,∞, Gibbs free energies, ΔG1E,∞, and entropy term, TrefΔS1E,∞). The effectiveness of the investigated deep eutectic solvents was based on the separation parameters (selectivities and capacity) values. These extraction parameters give a clear indication on how much of solvent would be required for a specific extraction and how selective the solvent is towards solutes to be separated. The results also reveal the ability of the investigated deep eutectic solvents to dissolve the solutes. The investigated deep eutectic solvents (DESs) were found to be useful in separating mixtures comprising (alkane-alcohol and acetone-ethanol). The influence of percentage loading, molar ratio as well as the influence of hydrogen bond donor was discussed.

Sensitivity of SnO2 nanoparticles/reduced graphene oxide hybrid to NO2 gas: a DFT study

The sensitivity of SnO2 nanoparticles/reduced graphene oxide hybrid to NO2 gas is discussed in the present work using density functional theory (DFT). The SnO2 nanoparticle shapes are taken as pyramids, as proved by experiments. The reduced graphene oxide (rGO) edges have oxygen or oxygen-containing functional groups. However, the upper and lower surfaces of rGO are clean, as expected from the oxide reduction procedure. Results show that SnO2 particles are connected at the edges of rGO, making a p-n heterojunction with a reduced agglomeration of SnO2 particles and high gas sensitivity. The DFT results are in good agreement with the experimental characterization of both SnO2 and rGO using energy gap and X-ray photoelectron spectroscopy (XPS) values. Gibbs free energy, enthalpy, and entropy of the various considered reactions are calculated. Results show that the sensitivity of the rGO/SnO2 hybrid to NO2 gas is the result of the interplay of the dissociation and oxidation reactions of NO2 gas. The sensitivity of the rGO/SnO2 hybrid to NO2 increases with temperature until the NO2 dissociation in the air reduces the concentration of NO2.

Thermodynamic Formation Properties of Point Defects in Germanium Crystal.

Point defects are crucial in determining the quality of germanium crystals. A quantitative understanding of the thermodynamic formation properties of the point defects is necessary for the subsequent control of the defect formation during crystal growth. Here, molecular dynamics simulations were employed to investigate the formation energies, total formation free energies and formation entropies of the point defects in a germanium crystal. As far as we know, this is the first time that the total formation free energies of point defects in a germanium crystal have been reported in the literature. We found that the formation energies increased slightly with temperature. The formation free energies decreased significantly with an increase in temperature due to the increase in entropy. The estimated total formation free energies at the melting temperature are ~1.3 eV for self-interstitial and ~0.75 eV for vacancy, corresponding to a formation entropy of ~15 kB for both types of point defects.

Adsorption behavior of Cr(VI) by biomass-based adsorbent functionalized with deep eutectic solvents (DESs)

This study was aimed to evaluate the performance of DESs functionalized peanut shell (PSD) as biosorbent for removing Cr(VI) from water. The effects of pretreatment, initial concentration, adsorption temperature, kinetics, adsorption isotherm, and thermodynamics were investigated. Scanning electron microscopy (SEM) and Point of Zero charge (pHpzc) techniques were used for characterization of the adsorbents. The results showed that the rigid structure of peanut shell was broken down after DESs modification and the point of zero charge was 6.02 for peanut shell and 6.84 for PSD, which exhibited a slightly acid character. Based on the comparisons of linear and nonlinear analysis of four kinetic models and four isotherms, the pseudo-second-order kinetic model was found to be suitable for describing the adsorption process. The presence of a boundary effect was observed within the range of research, indicating that internal diffusion was not the only rate-controlling step. The equilibrium data were well represented by the Langmuir model rather than the Freundlich, Temkin, and Dubinin–Radushkevich models. The maximum capacity derived was 5.36 mg g−1. Changes in Gibb’s free energy, enthalpy, and entropy revealed that Cr(VI) adsorption onto modified peanut-shell powders was a spontaneous and endothermic process. However, the highest desorption efficiency was only 8.77% by using NaOH as a desorbing agent.Graphical abstract

Villain transformation for XXZ anisotropic ferrimagnetic spin chain

We investigate the spin excitation spectrum and the thermodynamic properties of the XXZ anisotropic ferrimagnetic spin-(1/2, 1) chain under the presence of a magnetic field using the Villain transformation method. The effect of the XXZ anisotropic parameter and external magnetic field on the thermodynamic observables are calculated at finite temperature. The energy spectra exhibit the coexistence of a gapless branch and a gapful branch, both of them are sensitive to the change of XXZ anisotropic parameter. The gapless branch exhibits a V-shape structure, while the gapful branch is reversed and presents an omega-shape for the XY model which is completely different from previous results for the XXZ model. Thermodynamic quantities such as free energy, internal energy, entropy, specific heat and magnetization are present. These findings for the isotropic case are compared with the results calculated by the other established methods and it turns out that Villain transformation well describes this system at low temperature. • The spin excitation spectrum and thermodynamic properties of the XXZ anisotropic ferrimagetic spin-(1/2, 1) chain under the presence of magnetic field are investigated by the Villain transformation method. • Two branches of the excitation energy spectra are obtained, which are sensitive to the size of the XXZ anisotropic parameter. • The gapless branch exhibits a V-shape structure, while the higher branch is reversed and exhibits an omega-shape structure for the XY model. • The dependence of the thermodynamic quantities on the XXZ anisotropic parameter and magnetic field are studied.

Influence of organic and inorganic precipitators on the efficiency of surfactants extraction from wastewater by flotation

The chemical structure of surfactants causes their accumulation on the surface of water sources and leads to the formation of stable foam, which prevents the access of oxygen to the water and leads to the death of hydrobionts and deterioration in water quality. Therefore, the extraction of surfactants from wastewater is an urgent task. Increase the efficiency of flotation extraction of cationic surfactants, namely hexadecyl pyridinium chloride [C 16 H 33 NC 5 H 5]Cl (CHDP) and surfactants based on it - cetazol, by introducing organic – (sodium alkyl sulfate (SAS), CnH 2n+1 OSO 3 Na, n=10-16), and inorganic - potassium hexacyanoferrate (II, III) precipitators. The solubility of the products of interaction of cationic surfactants with SAS (sublates) was determined, which are extracted from solutions at different temperatures and impurities of electrolytes. The Gibbs free energy (), enthalpy (), and entropy (), which take place in the process of dissolution, are calculated. The low value of the heat of dissolution (2.1-16.6 kJ/mol) indicates a small effect of temperature on the solubility of sublates. The thermodynamic analysis of the process of formation of sublates allows determining the optimal length of the hydrocarbon radical of the precipitator. It is established that the extraction of the studied cationic surfactants should be extracted from water solutions and wastewater by the method of precipitation flotation using organic and inorganic precipitators. The presence of electrolytes and an increase in temperature leads to an increase in the degree of extraction hexadecyl pyridinium alkyl sulphonates sublates.

Electrospun magnetic La2O3–CeO2–Fe3O4 composite nanofibers for removal of fluoride from aqueous solution

La2O3–CeO2–Fe3O4 composite nanofibers (LCF NFs) were fabricated via a facile electrospinning - calcination approach, and evaluated as an adsorbent for defluoridation from aqueous solution under batch mode. The pseudo-second-order (PSO) model described defluoridation characteristics well under 20 and 50 mg/L. F− adsorption under 288.15–308.15 K obeyed the Langmuir adsorption isotherm better with the maximum uptakes of 202.43–229.89 mg/g, respectively. The obtained thermodynamics constants involving Gibbs free energies change (ΔG < 0), enthalpy (ΔH 9.90 kJ/mol), and entropy (ΔS 56.63 J/mol/K) unveiled that the defluoridation process was spontaneous natural as well as endothermic. After four repeated cycles, the developed LCF11 NFs revealed favorable regeneration ability, indicating that LCF11 NFs are auspicious and stable candidates for defluoridation of wastewater.

Early potential evaluation of lead compounds from a DNA-encoded library by the determination of their thermodynamics through a chromatographic method based on immobilized β2-adrenoceptor

Early potential evaluation of lead compounds is critical to decrease downstream lead-optimization cycle times and clinical attrition rates for drug development. This increasingly necessitates the methodologies for accurately evaluating the potential compounds. This work immobilized β2-adrenoceptor (β2-AR) onto microspheres through Halo-tag mediated reaction. Characterizing the resulting microspheres by elemental and functional analysis, we utilized the immobilized receptor to determine the thermodynamics of terbutaline, tulobuterol, clorprenaline, salbutamol, and methoxyphenamine. The association constants correlated to their capacity factors on the column containing the immobilized β2-AR, thus providing a possibility for early potential evaluation of lead compounds from complex matrices like a DNA-encoded library. By this model, the lead compound (XC267) was predicted to have an association constant higher than terbutaline, salbutamol, and methoxyphenamine, but lower than tulobuterol and clorprenaline. The binding interaction between XC267 and β2-AR is a spontaneous endothermic process with an association constant of (6.62 ± 0.13) × 104 M−1 at 37 °C. The change of Gibbs free energy(ΔGθ), enthalpy change (ΔHθ), and entropy change (ΔSθ) was −28.49 kJ/mol, −10.58 kJ/mol, and 57.79 J/moL·K at 37 °C. By the semi-empirical rule of Ross, the driving force of the interaction between XC267 and β2-AR was electrostatic interaction. Such binding force was also achieved by molecular docking. These results suggested that XC267 is a candidate to treat asthma by specific binding to β2-AR. We reasoned that receptor chromatography is able to the early potential evaluation of lead compounds from complex matrices.

A cost-effective eutectic high entropy alloy with an excellent strength–ductility combination designed by VEC criterion

Due to the excellent combination of strength and ductility, eutectic high entropy alloys (EHEAs) are of great interests to the researchers. Here, a cobalt free cost-effective eutectic high entropy alloy was designed by VEC criterion. The cobalt element in AlCoCrFeNi2.1 alloy is replaced by Fe and Ni in equal proportions to maintain VEC value unchanged. The designed AlCrFe1.5Ni2.6 alloy exhibited a eutectic microstructure composed of FCC (L12) phase and BCC (B2) phase. The room temperature mechanical properties of the designed alloy were comparable to those of AlCoCrFeNi2.1 EHEA and better than those of a majority of as-cast high entropy alloys. An excellent combination of strength and ductility originates from the hetero-interface strengthening and slip continuity across the Kurdjumov-Sachs (K–S) interface. The present work proves the VEC criterion could successfully be used to design the cost-effective eutectic high entropy alloy and the designed alloy has a great potential in engineering applications.

Phase transition in a stochastic geometry model with applications to statistical mechanics

We study the connected components of the stochastic geometry model on Poisson points which is obtained by connecting points with a probability that depends on their relative position. Equivalently, we investigate the random clusters of the random connection model defined on the points of a Poisson process in d‐dimensional space where the links are added with a particular probability function. We use the thermodynamic relations between free energy, entropy, and internal energy to find the functions of the cluster size distribution in the statistical mechanics of extensive and nonextensive. By comparing these obtained functions with the probability function predicted by Penrose, we provide a suitable approximate probability function. Moreover, we relate this stochastic geometry model to the physics literature by showing how the fluctuations of the thermodynamic quantities of this model correspond to other models when a phase transition (10.1002/mma.6965, 2020) occurs. Also, we obtain the critical point using a new analytical method.

Synthesis of MIL-101(Cr)/Sulfasalazine (Cr-TA@SSZ) hybrid and its use as a novel adsorbent for adsorptive removal of organic pollutants from wastewaters

Metal–organic frameworks (MOFs) are currently considered as strong adsorbents to remove organic pollutants due to their unique characteristics. The main aim of this study is to synthesize the MIL-101(Cr)/Sulfasalazine (Cr-TA@SSZ) hybrid by a hydrothermal approach for the first time. Due to the presence of different functional groups such as amino, hydroxyl, and carboxyl in the structure of Sulfasalazine and its good activity, this compound can be a suitable auxiliary ligand to improve the surface of the MIL-101(Cr). The synthesized Cr-TA@SSZ was applied for the adsorption of terephthalic acid (TA), para-toluic acid (p-tol), and benzoic acid (BA) also the results were compared with MIL-101(Cr). The Cr-TA@SSZ and MIL-101(Cr) were characterized by the general tests including, X-ray diffraction (XRD), Fourier transform infrared (FTIR), Brunauer–Emmett–Teller (BET), transmission electron microscopy (TEM), scanning electron microscope (SEM), thermal gravimetric analysis (TGA), differential thermal analysis (DTA), zeta potential, and energy dispersive X-ray analysis (EDX). Based on the above analyses, it was concluded that Cr-TA@SSZ has a different composition and network structure than the MIL-101(Cr). The formula for the new MOF (Cr-TA@SSZ) is proposed as: $${\text{Cr}}_{{3}} {\text{F }}\left( {{\text{H}}_{{2}} {\text{O}}} \right)_{{2}} {\text{O}}\left[ {{\text{C}}_{{6}} {\text{H}}_{{4}} \left( {{\text{CO}}_{{2}} } \right)_{{2}} } \right]\left[ {{\text{C}}_{{6}} {\text{H}}_{{3}} {\text{N}}\left( {{\text{OH}}} \right)\left( {{\text{CO}}_{{2}} } \right)} \right],{ 2}.{\text{5H}}_{{2}}.$$ The experiments for evaluating the effect of the different parameters such as pH, initial concentration, contact time, and temperature on the removal of the terephthalic acid (TA), para-toluic acid (p-tol), and benzoic acid (BA) were carried out in batch mode. The results show that equilibrium was achieved after that 1440 min. As results, TA and p-tol at pH 5 and BA at pH 2–5 have the highest adsorption rate for the Cr-TA@SSZ, while the highest uptake for MIL-101(Cr) was obtained for all three solutes at pH 5. Removal percent was found to be dependent on the initial concentration of solutes. The Cr-TA@SSZ has the highest percentage removal of benzoic acid, terephthalic acid (TA), and p-toluic acid (p-tol) at an initial concentration of 100 ppm (81%, 90%, and 87% respectively), while the highest percentage removal for the MIL-101(Cr) are 70%, 84%, and 72% respectively. The isotherm, kinetic and thermodynamic models were also analyzed for TA, p-tol, and BA adsorption. Equilibrium adsorption was evaluated employing Langmuir, Freundlich, Temkin, Redlich–Peterson (R–P), and Dubinin–Radushkevich (D–R) equations, in which Langmuir and Redlich–Peterson models were in good agreement with the experimental results. The maximum adsorption capacities (q0) derived from the Langmuir model for the Cr-TA@SSZ were determined to be 2208.4 mg/g, 1241.2 mg/g, and 1009.5 mg/g for TA, p-tol, and BA, respectively while for MIL-101(Cr) the maximum adsorption capacities were determined to be 1692.0 mg/g, 952.4 mg/g, and 769.2 mg/g respectively. The Cr-TA@SSZ was found to be more efficient in the removal of terephthalic acid (TA), para-toluic acid (p-tol), and benzoic acid (BA) from water than the MIL-101(Cr). Also, the results showed that a pseudo-second-order kinetic model with a higher correlation coefficient (R2 > 0.99) matched well for the adsorption of terephthalic acid (TA), para-toluic acid (p-tol), and benzoic acid (BA) onto MIL-101(Cr) and Cr-TA@SSZ. The thermodynamic parameters such as a change in Gibbs free energy (ΔG), enthalpy (∆H), and entropy (ΔS) were determined. The negative values of ΔG indicated that the removal process was spontaneous at all temperatures. Further, the values of ∆H indicated the exothermic nature of the removal process. Moreover, adsorption experiments using industrial wastewater from a TA production plant showed that Cr-TA@SSZ could be used as a promising adsorbent in the adsorptive removal of organic pollutants from wastewaters. This MOF removed 40% COD from the concentrated phase (equivalent to 13,000 ppm) and 77.3% COD from the diluted phase (equivalent to 4250 ppm) wastewater. Reusability of the Cr-TA@SSZ in six cycles indicated the adsorbent's appropriate performance for industrial applications.

Biochemical Characteristics and Healing Activity of Bromelia laciniosa Leaf Protease

Macambira plant (Bromelia laciniosa Mart. Ex Shult. &amp; Schult. f.) is a species belonging to the family Bromeliaceae, which is distributed widely in the hinterlands of northeastern Brazil, from Bahia to Piauí states. The plants of this species contain an enzyme complex named bromelain, which has great potential for therapeutic applications. In the present study, bromelain derived from Bromelia laciniosa leaves was assessed for its thermodynamic properties and in vitro cytotoxic and healing activities. Bromelain was extracted from the leaves and partitioned using ethanol. The partially purified bromelain was then characterized to determine the optimum pH and temperature and the kinetic and thermodynamic parameters. The partially purified bromelain derived from macambira leaves exhibited its highest activity at 47°C and pH 7, when the Km and Vmax values of 2.26 µM and 2.083 U/mL, respectively. The half-life of this bromelain at 47°C was 5.78 h. At 47°C, the Gibbs's free energy, enthalpy, and entropy values reached 89, 53.54, and –0.11 kJ/mol K, respectively. In the SDS-PAGE analysis, bromelain appeared as the main protein band, with an estimated molecular mass of 33 kDa. The in vitro cytotoxic activity and wound healing effects were determined using the MTT assay and Scratch assay, respectively. These assays were performed on the non-neoplastic cell lines L-929 and PBMC and the human tumor cell lines MCF-7, HCT-116, and NCI-H292. Bromelain exhibited a positive healing activity with a change rate similar to that observed for the control. In addition, bromelain exhibited cytotoxic activity against NCI-H292 tumor cells and chemopreventive potential. These results indicate that bromelain derived from macambira leaves may be utilized as a potential ingredient in pharmaceutical formulations, for various healing and chemopreventive purposes and as an alternative to the bromelain extracted from pineapple. In addition, the biochemical characteristics of this bromelain could find application in the food industry. Future studies should, therefore, focus on deciphering the action mechanisms underlying the activities of bromelain observed in the present study to further confirm and enhance its application potential for therapeutic purposes.

Experimental Spectroscopic, Structural (Monomer and Dimer), Molecular Docking, Molecular Dynamics Simulation and Hirshfeld Surface Analysis of 2-Amino-6-Methylpyridine

2-Amino-6-methylpyridine (2-AMP) was investigated experimentally using FT-IR, 1H, NMR, and UV-Vis spectra, as well as theoretically using DFT calculations. The quantum computational calculations (the optimized structure, FT-IR, NMR and UV-Vis.) to support experimental data were performed by DFT approach at B3LYP functional and 6–311 + +G(d,p) basis set. The optimized molecular geometry and wavenumber calculations were done in the gas phase, while theoretical NMR was performed in Chloroform (CHCL3) solvation. The “Potential Energy Distribution analysis” (PED) of the title compound was performed with VEDA analysis and these assignments were compared with the experimental FT-IR spectrum. Hirshfeld analysis was also performed and analyzed intermolecular interactions on the surface of crystal, However, the most significant contributions to the Hirshfeld surface come from N···H (17.3%), C···H/H···C (23%) and H···H (68.8%). Chemical reactivity studies, Molecular Electrostatic Potential (MEP) maps, and surface area maps were also conducted. To show electron delocalization in the molecule, researchers used the electron localization function (ELF). Other topics included topological and mulliken charge distribution studies. Natural Bond Order Analysis (NBO) was performed to interpret intermolecular charge transfer.The effect of temperature on thermodynamical parameters such as Gibbs free energy, enthalpy, and entropy was examined. TD-DFT analysis was also used to shed more light on how the electronic transitions in the UV–Vis spectra were estimated. For different solvents, the estimated maximum wavelength (λ) absorbance and the band-gap energy of 2-AMP were calculated and compared to experimental results. The molecule's bioactivity is described theoretically using the Electrophilicity index and the interaction between the ligand-protein is depicted using Molecular docking. The proteins 3DQS, 4UX6, 5ADF, 5TUD, and 6E9L were studied via molecular docking. The nature of the molecule was determined by its drug-likeness. A molecular dynamics simulation was used to explore biomolecular stability.

Adsorptive Behavior of Tartaric Acid Treated Holarrhena antidysenterica and Citrullus colocynthis Biowastes for Decolourization of Congo Red Dye from Aqueous Solutions

The aim of the present work is to eradicate Congo red (CR) dye from aqueous solutions since the dye compounds are harmful to human life and the environment leading to detrimental results. For this purpose, Holarrhena antidysenterica (HA) and Citrullus colocynthis (CC) adsorbents were used for the adsorptive removal of Congo red dye from wastewaters. The unmodified adsorbents (U-HA and U-CC) were chemically modified using tartaric acid (TA). Morphological structures were examined by FTIR and SEM. Batch adsorption studies were tested at a variety of pH, time exposure, temperatures, and adsorbent dosages. Thermodynamic parameters such as Gibbs free energy ( ∆ G ° ), enthalpy ( ∆ H ° ), entropy changes ( ∆ S ° ), and energy of activation ( E a ) were also calculated. The results revealed that tartaric acid-Citrullus colocynthis (TA-CC) gave optimum conditions of time of contact (35 min), temperature conditions (40°C), pH (3), and dosage of adsorbent (1.6 g) for maximum dye removal. Tartaric acid-Holarrhena antidysenterica (TA-HA) gave equilibrium time of contact (30 min), temperature (40°C), and pH optimum (2) along with a 1.6 g dosage of adsorbent. Mechanistic understanding of adsorption isotherm provided that the Langmuir model was followed by raw and modified adsorbents. Maximum adsorption capacities Q max attained were 60.61 (mg g-1), 128.21 (mg g-1), 87.71 (mg g-1), and 131.57 (mg g-1), respectively, for U-HA, TA-HA, U-CC, and TA-CC. The results of kinetic modeling displayed a high value of R 2 (0.99) along with minimal error (RMSE) for dye removal showing that the pseudo-second-order kinetic model has acceptable accuracy. Fourier transform infrared proposed the electrostatic, pi-pi interactions, and hydrogen bonding as dominant adsorption mechanisms at acidic pH, respectively. Rate-determining steps comprise both surface and intraparticle diffusions. Thermodynamics indicated that the dye adsorption of CR is spontaneous, exothermic, and favorable in nature. These agricultural wastes due to specific points such as low cost, availability, and high removal rates of adsorption are highly competent for the expulsion of anionic dye like CR from wastewaters.

Experimental Investigation on Reactive Orange 16 Removal Using Waste Biomass of Ulva prolifera

Ulva prolifera marine seaweed was tested for its capacity to eliminate reactive orange 16 (RO16) from aqueous solutions. Algae has recently been regarded as one of the most environmental friendly wastewater treatment methods and resources. The batch study used variations in solution pH, sorbent dosage, initial dye concentration, and temperature. The biochar was characterized using Fourier transform infrared (FT-IR) spectroscopy, an elemental analyser, proximate analysis, and a BET analyser. The adsorption mechanism was further investigated using adsorption isotherm and kinetic models. The thermodynamic analysis was performed by varying temperatures at different dye concentrations and calculating thermodynamic parameters such as Gibbs free energy, enthalpy, and entropy. The study was performed to evaluate the sorbent’s performance in real-time wastewater treatment, a variety of chemicals, solid-liquid ratios, and regeneration cycles that were used to determine desorption efficiency.

Enhancement of the performance of the GH75 family chitosanases by fusing a carbohydrate binding module and insights into their substrate binding mechanisms

Chitooligosaccharides (COSs) with relatively higher degrees of polymerization (DP) exhibited better biological properties than COSs with lower DP. Here, we demonstrated a potential strategy to enhance the affinity, activity, and thermostability of the chitosanase Csn75 from Aspergillus fumigatus CJ22-326 through fusion of a carbohydrate binding module (CBM) that can specifically bind to chitosan. Compared with the Csn75, the specific enzyme activity of the Csn75-CBM32 and the Csn75-2CBM32 had increased by 59.18% and 14.29%, respectively. The free energy (ΔG), enthalpy (ΔH), and entropy (-TΔS) of the three enzymes (Csn75, Csn75-CBM32, and Csn75-2CBM32) toward (GlcN)6 was (−7.19, −7.54, and −8.08 kcal/mol), (−5.37, 1.75, and 0.86 kcal/mol), and (1.45, 9.27, and 8.03 kcal/mol), respectively. The substrate binding of the Csn75 and the fusion enzymes (Csn75-CBM32 and Csn75-2CBM32) were mainly driven by the hydrophobic (entropy effect) and favorable intermolecular forces (enthalpy contribution), respectively. Moreover, the DP of COSs in the final hydrolysate of Csn75 was 2–4, but that of Csn75-CBM32 and Csn75-2CBM32 was 3–5. This strategy provides a potential alternative for the bioproduction of desirable COSs to meet the requirement of application in food systems.