Values Of Thermodynamic Parameters Research Articles

Cadmium biosorption using Aloe. barbadensis Miller leaves waste powder treated with sodium bicarbonate

The research on Aloe.barbadensis Miller leaves powder use which is related to environmental application such as clean water technology/wastewater treatment process has been focused on the removal of cadmium, Cd(II). The present investigation describes the use of Aloe. Barbadensis Miller leaves powder treated with chemical Na 2 CO 3 as bio-adsorbent, ( MABL ) for Cadmium removal from aqueous solutions. Batch experiments were performed to study the effects of various parameters, such as pH, dosage, contact time, initial metal concentration on the removal behavior of Cd (II) from aqueous solutions. The kinetic data fitted well to the pseudo-second order model, with a calculated adsorption capacity (q e ) value of 17.54 mg/g at 20 ppm. The biosorption data conformed best to the Freundlich isotherm as revealed by a lower non-linear Chi-square (x 2 ) value of 0.32 and a higher correlation value of 0.99 at 293 K.The maximum biosorption capacity for the leaves powder was 23.86 mg/ g at 313 K. The thermodynamic parameters values vary with concentration. The negative ΔG value indicates the reaction to be spontaneous, the negative ΔH at different concentrations indicates the reaction to be exothermic, less than 1 value of S*sticking probability showed that biosorption process was feasible and bioadsorbent was suitable to the removal of Cd (II) from aqueous solutions. Fourier transform infrared (FTIR) spectroscopy confirmed the involvement of OH, C=C, and C-O groups on the removal of Cd (II) from aqueous solutions. Scanning electron microscopy, Zeta potential, BET characterizations of the bioadsorbent were also performed. This study indicated that Modified Aloe. barbadensis Miller leaves powder ( MABL ) can be used very effectively to remove Cd (II) from aqueous solutions as well as real wastewater. • Modified A. barbadensis Miller Leaves powder as low cost efficient Biosorbent • Effect of process parameters such pH, concentration, biosorbent doses, temperature • To determine the isotherms and kinetic models • Thermodynamic study of the biosorbent-Cd(II) aqueous system

Kinetic and isotherms modeling of methyl orange and chromium (VI) onto hexagonal ZnO microstructures as a membrane for environmental remediation of wastewater

Globally, contamination of water by dyes and heavy metals (HMs) is a serious environmental and public health problem due to their carcinogenic and mutagenic nature. It is incumbent to treat innocuously before discharge. It is the first time, hexagonal zinc oxide (ZnO) microstructure are being employeed as a membrane in the simultaneous removal of methyl orange (MO) and chromium (Cr (VI)) from the aqueous solution. The surface chemistry of hexagonal ZnO was characterized for morphology, surface functional groups, crystalline nature, and elemental composition by scanning electron microscope (SEM), Fourier transmission infrared spectroscopy (FTIR), X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX). Adsorption capacity and removal efficiency was determined by the laboratory batch adsorption experiments, while nonlinear, linear kinetics and isotherm models were fitted to experimental data to investigate the adsorption process. The results exhibited that the maximum adsorption capacity (qmax) of hexagonal ZnO from the Langmuir isotherm model was 80.39 mg g−1 and 84.10 mg g−1 for MO and Cr (VI) respectively. According to the modeling findings, linear langmuir fitted to the experimental data with R2 0.967 and 0.971 for both MO and Cr (VI) which indicates monolayer physical adsorption of both pollutants has taken place. Whereas, kinetic study showed nonlinear pseudo-second order with R2 0.989 and 0.986 for MO and Cr (VI) model best fitted with the experimental data. The values of thermodynamics parameters Gibbs free energy change ΔG°, heat of enthalpy ΔH° and, heat of entropy ΔS° indicate that spontaneous, endothermic, and irreversible adsorption reactions occurred. Overall, it is concluded from our observations that hexagonal ZnO has the potential to be used as an eco-friendly, cost-effective adsorbent for simultaneous remaoval of both MO and Cr (VI) from water. Findings of the current investigation provide valuable insights for the development of an inexpensive, effective and sustainable filtration method for the treatment of MO and Cr (VI) synergistically.

Insight into the removal of vanadium ions from model and real wastewaters using surface grafted zirconia-based adsorbents: Batch experiments, equilibrium and mechanism study

This study concerns the fabrication of CTAB- and N,N-dimethyltetradecylamine-grafted zirconia and evaluation of their ability to adsorb vanadium ions. The effectiveness of ZrO2 functionalization and the different nature of the modifiers used were confirmed by differences in the porosity (ZrO2: SBET = 347 m2/g; ZrO2-CTAB: SBET = 375 m2/g, ZrO2–NH+: SBET = 155 m2/g), types of functional groups, and isoelectric points (the ZrO2 and CTAB-modified samples have IEPs = 3.8 and 3.9, ZrO2–NH+ has IEP = 7.1) of the prepared adsorbents. The designed materials were tested in batch adsorption experiments involving the removal of vanadium ions from model wastewaters at various process parameters, among which pH proved to be the most important. Based on equilibrium and kinetic evaluations, it was proved that the sorption of V(V) ions followed pseudo-second-order and intraparticle diffusion models, and the data were better fitted to the Langmuir model, suggesting the following order of the sorbents in terms of favorability for V(V) ion adsorption: ZrO2–NH+ > ZrO2 > ZrO2-CTAB. The estimated maximum monolayer capacity of ZrO2–NH+ for V(V) (87.72 mg/g) was the highest among the tested materials. Additionally, it was confirmed that adsorption of V(V) ions onto synthesized materials is a heterogeneous, exothermic, and spontaneous reaction, as evidenced by the calculated values of thermodynamic parameters. The key goals included the transfer of experimental findings obtained using model solutions to the adsorption of V(V) ions from solutions arising from the leaching process of spent catalysts. The highest adsorption efficiencies of 70.8% and 47.5% were recorded for the ZrO2–NH+ material in acidic solution; this may be related to the protonization of –NH+ groups, which favors the sorption of V(V) ions. Based on desorption tests as well as the results of infrared and X-ray photoelectron spectroscopy, irrespective of the process conditions, the physical nature of the adsorbent/adsorbate interaction was confirmed.

Adsorption of Chlormethine Anti-Cancer Drug on Pure and Aluminum-Doped Boron Nitride Nanocarriers: A Comparative DFT Study.

The efficacy of pure and aluminum (Al)-doped boron nitride nanocarriers (B12N12 and AlB11N12) in adsorbing Chlormethine (CM), an anti-cancer drug, was comparatively dissected by means of the density functional theory method. The CM∙∙∙B12N12 and ∙∙∙AlB11N12 complexes were studied within two configurations, A and B, in which the adsorption process occurred via N∙∙∙ and Cl∙∙∙B/Al interactions, respectively. The electrostatic potential affirmations confirmed the opulent ability of the studied nanocarriers to engage in delivering CM via two prominent electrophilic sites (B and Al). Furthermore, the adsorption process within the CM∙∙∙AlB11N12 complexes was noticed to be more favorable compared to that within the CM∙∙∙B12N12 analog and showed interaction and adsorption energy values up to –59.68 and −52.40 kcal/mol, respectively, for configuration A. Symmetry-adapted perturbation theory results indicated that electrostatic forces were dominant in the adsorption process. Notably, the adsorption of CM over B12N12 and AlB11N12 nanocarriers exhibited predominant changes in their electronic properties. An elemental alteration was also revealed for the softness and hardness of B12N12 and AlB11N12 nanocarriers before and following the CM adsorption. Spontaneity and exothermic nature were obviously observed for the studied complexes and confirmed by the negative values of thermodynamic parameters. In line with energetic manifestation, Gibbs free energy and enthalpy change were drastically increased by the Al doping process, with values raised to –37.15 and –50.14 kcal/mol, respectively, for configuration A of the CM∙∙∙AlB11N12 complex. Conspicuous enhancement was noticed for the adsorption process in the water phase more than that in the gas phase and confirmed by the negative values of the solvation energy up to −53.50 kcal/mol for configuration A of the CM∙∙∙AlB11N12 complex. The obtained outcomes would be the linchpin for the future utilization of boron nitride as a nanocarrier.

Removal of diphenols using pine biochar. Kinetics, equilibrium, thermodynamics, and mechanism of uptake

Thermal pyrolysis synthesized activated biochar from the Pinus elliottii sawdust (PS) at 600° C. The obtained activated biochar (PB600) was used for the removal of three diphenols, catechol (CAT), resorcinol (RES), and hydroquinone (HYD), which are utilized mainly in different industries. The PB600 was characterized by several analytical techniques. The BET surface area of 1473 m2.g−1 and a total pore volume of 0.707 cm3 g−1 was obtained. The functional groups and amount of acidic and basic groups on the biochar were determined by FTIR and Bohem titration, respectively. From the isotherm studies, it was obtained that the maximum adsorption capacities (Qmax) based on the Liu isotherm model were 419.8 (CAT 45 °C), 263.8 (RES 40 °C), and 500.9 mg g−1 (HYD 25 °C). The values of thermodynamic parameters demonstrated that CAT, RES, and HYD adsorption processes were spontaneous, exothermic, and energetically favorable, and the magnitude of ΔH° was compatible with physisorption. The CAT, RES, and HYD adsorption mechanism onto the biochar is followed by porous filling, π-π interactions, and hydrogen bonds. Subsequently, PB600 biochar was employed as a potential adsorbent for treating simulated industrial effluents in a complex matrix simulating a real industrial effluent, and the overall removal attained up to 95.97 %. In concert with the experimental results, the electronic properties of the developed adsorption systems, including frontier molecular orbitals, charge density difference, and partial density of states, were studied by the density functional theory (DFT) approach to explore the mechanism of adsorption on the activated biochar surface.

Quantification of Caffeine Interactions in Choline Chloride Natural Deep Eutectic Solvents: Solubility Measurements and COSMO-RS-DARE Interpretation.

Solubility of active pharmaceutical ingredients is an important aspect of drug processing and formulation. Although caffeine was a subject of many studies aiming to quantify saturated solutions, many applied solvents suffer from not being environmentally friendly. This work fills this gap by presenting the results of solubility measurements in choline chloride natural deep eutectic solvents, ccNADES, comprising one of seven of the following polyalcohols: glycerol, sorbitol, xylitol, glucose, sucrose, maltose and fructose. The ratio of ccNADES components was optimized for maximizing caffeine solubility at room temperature. Additionally, temperature dependent solubility was measured for the first four systems exhibiting the highest solubility potential, both in their neat forms and in mixtures with water. Results were used for intermolecular interactions assessments using the COSMO-RS-DARE approach, which led to a perfect match between experimental and computed solubility values. An important methodological discussion was provided for an appropriate definition of the systems. Surprising linear trends were observed between the values of fitting parameters and water-ccNADES composition. In addition, comments on selection of the values of the fusion thermodynamic parameters were provided, which led to the conclusion that COSMO-RS-DARE solubility computations can effectively compensate for the inaccuracies of these important physicochemical properties.

An approach to the activation energy, thermodynamics, and flow injection kinetics of degradation of 2,4-dimethylaniline

Flow injection kinetics was used to investigate the activation energy and thermodynamics parameters of periodate degradation of 2,4-dimethylaniline by catalyzing the reaction with Mn(II) in a mixed medium. The impact of pH and dielectric constant was also investigated. Flow injection kinetics, activation energy, and several thermodynamic parameters have also been recorded. The value of activation energy (ΔE#) for the degradation of 2,4-dimethylaniline is 4.5350 ± 0.1302 kJmol−1, which is consistent with the speculative first-order. The value of other thermodynamic parameters were reported as Arrhenius frequency factor (A) = 3.7660 × 106 ± 0.00372 dm3mol−1s−1; Activation Entropy (ΔS#) = −208.170 ± 0.1498 Jmol−1K−1, Activation free energy (ΔG#) = 66.59 ± 1.163 kJmol−1 and activation Enthalpy (ΔH#) = 1.954 ± 0.0465 kJmol−1.

Effect of pH on Diclofenac-Lysozyme Interaction: Structural and Functional Aspect.

As a nonsteroidal antiinflammatory drug, diclofenac (DCF) is used in the treatment of a variety of human ailments. It has already been reported that the use of this class of drugs for a longer duration is associated with numerous side effects such as cardiovascular implications, reno-medullary complications, etc. In the present study, the effect of DCF on the structure, stability, and function of lysozyme was studied. The study was designed to examine the effect of DCF only at various pH values. Heat-induced denaturation of lysozyme was analyzed in the presence and absence of various molar concentrations of DCF at different pH values. The values of thermodynamic parameters, the midpoint of denaturation (T m), enthalpy change at T m (ΔH m), constant pressure heat capacity change (ΔC p), and Gibbs energy change at 25°C (ΔG D o), thus obtained under a given set of conditions (pH and molar concentration of DCF), demonstrated the following 1) DCF destabilized lysozyme with respect of T m and ΔG D o at all the pH values, 2) the magnitude of protein destabilization is lesser at acidic pH than at physiological pH, 3) structural changes in lysozyme are less projecting at pH 2.0 than at pH 7.0, and 4) quenching is observed at both pH values. Furthermore, the process of protein destabilization in the presence of DCF is entropically driven.

(Keynote) An in Situ View of Nucleation and Coarsening at Solid-Electrolyte Interfaces

Nucleation of crystalline films at liquid-solid interfaces is widespread in both natural and synthetic systems. Observing this process is challenging, because it is a consequence of unstable density fluctuations, making the structures and events that must be probed both transient in nature and small in extent. Thus, the application of high-speed, molecularly resolved AFM to systems that assemble on surfaces provides a powerful method to quantify the dynamics and extract the underlying physics. Here we illustrate the fundamental insights into the pathways and energetics of nucleation and self-assembly made possible by this method using results from two contrasting systems: gibbsite (Al(OH)3) films grown on muscovite mica (001) and 2D arrays of peptides that self-assemble on both MoS2 (0001) and graphite. The results on gibbsite show that a dynamic population of clusters is created by continuous attachment and detachment of adsorbed ions, consistent with the basic concept of classical nucleation theory (CNT). However, severe discrepancies emerge when the values of key thermodynamic parameters are extracted from the data. Comparison to kinetic Monte Carlo simulations shows that electrostatic interactions between positively charged aluminum hydroxide clusters and the negative surface potential of mica is the source of these discrepancies, modifying both the chemical potential of the accumulating ions and the edge tension of the clusters. These interactions stabilize a nanostructured surface mesophase, which evolves gradually via a process of cluster growth and coalescence not limited by formation of a critically sized nucleus. The results for peptides on MoS2 show that the high anisotropy of inter-peptide interactions drives 2D assembly to occur row-by-row, starting with 1D nuclei. In agreement with expectations of CNT, these 1D nuclei form without a free energy barrier and there is no critical size. However, on graphite, two new phenomena emerge. First, peptide rows become highly mobile, enabling to a molecular level form of growth by oriented attachment. Second, appearance of the final phase is preceded by formation of a metastable phase, which dissolves as the stable phase nucleates. This manifestation of Ostwald’s Rule of Stages cannot be rationalized with the usual thermodynamic arguments due to the barrier-free nature of 1D nucleation. Instead, we propose a rationale rooted in chemical kinetics and applied here to peptide dimer formation at the surface.

Low-Error Estimation of Half-Cell Thermodynamic Parameters from Whole-Cell Li-Ion Battery Experiments: Physics-Based Model Formulation, Experimental Demonstration, and an Open Software Tool

Low C-rate charge and discharge experiments, plus complementary differential voltage or differential capacity analysis, are among the most common battery characterization methods. Here, we adapt the multi-species, multi-reaction (MSMR) half-cell thermodynamic model to low C-rate cycling of whole-cell Li-ion batteries. MSMR models for the anode and cathode are coupled through whole-cell charge balances and cell-cycling voltage constraint equations, forming the basis for model-based estimation of MSMR half-cell parameters from whole-cell experimental data. Emergent properties of the whole-cell, like slippage of the anode and cathode lithiation windows, are also computed as cells cycle and degrade. A sequential least-square optimization scheme is used for parameter estimation from low-C cycling data of Samsung 18650 NMC|C cells. Low-error fits of the open-circuit cell voltage (e.g., under 5 mV mean absolute error for charge or discharge curves) and differential voltage curves for fresh and aging cells are achieved. We explore the features (and limitations) of using literature reference values for the MSMR half-cell thermodynamic parameters (reducing our whole-cell formulation to a 1-degree-of-freedom fit), and demonstrate the benefits of opening up the degrees of freedom by letting the MSMR parameters be tailored to the cell under test, within constrained bounds near the half-cell reference values. Bootstrap analysis is performed on each dataset to show the robustness of our fitting to experimental noise and data sampling over the course of 600 cell cycles. The results show which specific MSMR insertion reactions are most responsible for capacity loss in each half-cell and the collective interactions that lead to whole-cell slippage and changes in useable capacity. Open-source software is made available to easily extend this model-based analysis to other labs and battery chemistries.

Ferritin Iron Responsive Elements (IREs) mRNA Interacts with eIF4G and Activates In Vitro Translation

Eukaryotic initiation factor (eIF) 4G plays an important role in assembling the initiation complex required for ribosome binding to mRNA and promote translation. Translation of ferritin IRE mRNAs is regulated by iron through iron responsive elements (IREs) and iron regulatory protein (IRP). The noncoding IRE stem-loop (30-nt) structure control synthesis of proteins in iron trafficking, cell cycling, and nervous system function. High cellular iron concentrations promote IRE RNA binding to ribosome and initiation factors, and allow synthesis of ferritin. In vitro translation assay was performed in depleted wheat germ lysate with supplementation of initiation factors. Fluorescence spectroscopy was used to characterize eIF4F/IRE binding. Eukaryotic initiation factor eIF4G increases the translation of ferritin through binding to stem loop structure of iron responsive elements mRNA in the 5'-untranslated region. Our translation experiment demonstrated that exogenous addition of eIF4G selectively enhanced the translation of ferritin IRE RNA in depleted WG lysate. However, eIF4G facilitates capped IRE RNA translation significantly higher than uncapped IRE RNA translation. Addition of iron with eIF4G to depleted WG lysate significantly enhanced translation for both IRE mRNA (capped and uncapped), confirming the contribution of eIF4G and iron as a potent enhancer of ferritin IRE mRNA translation. Fluorescence data revealed that ferritin IRE strongly interacts to eIF4G (Kd = 63 nM), but not eIF4E. Further equilibrium studies showed that iron enhanced (~4-fold) the ferritin IRE binding to eIF4G. The equilibrium binding effects of iron on ferritin IRE RNA/eIFs interaction and the temperature dependence of this reaction were measured and compared. The Kd values for the IRE binding to eIF4G ranging from 18.2 nM to 63.0 nM as temperature elevated from 5 °C to 25 °C, while the presence of iron showed much stronger affinity over the same range of temperatures. Thermodynamic parameter revealed that IRE RNA binds to eIF4G with ΔH = -42.6 ± 3.3 kJ. mole-1, ΔS = -11.5 ± 0.4 J. mole-1K-1, and ΔG = -39.2 ± 2.7 kJ. mole-1, respectively. Furthermore, addition of iron significantly changed the values of thermodynamic parameters, favoring stable complex formation, thus favoring efficient protein synthesis. This study first time demonstrate the participation of eIF4G in ferritin IRE mRNA translation. eIF4G specifically interacts with ferritin IRE RNA and promotes eIF4G-dependent translation.

Biosorption of crystal violet by nutraceutical industrial fennel seed spent equilibrium, kinetics, and thermodynamic studies

The present research aims to describe a study that would investigate the practicability of using nutraceutical industrial fennel seed spent (NIFSS) is one of the low-cost types of biosorbent which adsorbs a cationic dye, known as crystal violet (CV), from an aqueous solution. The effects of dye adsorption were also investigated: pH, adsorbent dosage, temperature, particle size, and initial dye concentration. Then the experimental equilibrium data attained was analyzed using isotherm models of Langmuir, Freundlich, Jovanovic, Vieth-Sladek, Brouers-Sotolongo, Redlich-Peterson, and Sips. Hence the use of Film diffusion, Pseudo-first-order, Pseudo-second-order, Dumwald-Wagner and Weber-Morris models for kinetic adsorption studies was done. The maximum experimental adsorption capacity, qe, was determined to be 140 mg g−1 at equilibrium conditions in the lab. The maximum adsorption of 166.73 mg g−1 was predicted by the Brouers-Sotolongo isotherm, which had the closest value of correlation coefficient (R2) of 0.987. Pseudo-second order model fits the kinetic data well in this paper. The thermodynamic parameter values such as ΔG°, ΔH°, and ΔS° demonstrated that the adsorption process was non-spontaneous and exothermic. The lower value of ΔH° shows the physical nature of the process. The CV was adsorbed onto NIFSS, as per the evidence by SEM images and FTIR spectra. The possibility of interaction in the CV-NIFSS system is discussed. To remove CV from an aqueous solution, NIFSS is a fast and effective adsorbent.

Physico-chemical characterization of bovine serum albumin-cationic gemini surfactant interaction

Being perspective candidates for bioapplications, gemini surfactant – protein interaction research is continuing extensively. In the work described herein, we have, therefore, investigated the binding of a recently synthesized biodegradable cationic diester-functionalized C14-E2O2-C14 gemini surfactant with ethylene oxide group in the spacer with the transport protein bovine serum albumin (BSA). The system properties were determined through a combination of surface tension measurements, multispectroscopic and computational analyses. The surface and interfacial properties of the concerned gemini got perturbed on interaction with BSA. The reduction in BSA fluorescence intensity was accredited to fluorescence quenching by the surfactant and relevant parameters (KSV and Kb; 14.70, 10.63, 7.27 × 104 M−1 and 25.63, 14.28, 7.20 × 104 M−1) have been computed at three different temperatures (288, 298 and 308 K), which demonstrated that C14-E2O2-C14 binds strongly with BSA protein through static quenching (UV–vis absorption analysis results were the same) with the binding stoichiometry 1:1. The obtained negative values of thermodynamic parameters (ΔGb0,ΔHb0 and ΔSb0) specified spontaneous process where hydrogen bonding and van der Waals forces are the major forces in the interaction mechanism. The effect of β-cyclodextrin (β-CD) has also been explored on the interaction and the values of KSV and Kb have been evaluated. Moreover, some other spectral results (CD, 3-D, synchronous, RRS, pyrene, FT-IR) confirmed that the interaction of the surfactant with BSA persuaded alterations in conformation of BSA. The molecular docking results as well as site probe measurements corroborated the ligand binding sites and interaction of the gemini surfactant with amino acid residues. The binding analysis of C14-E2O2-C14 gemini surfactant-BSA interaction is potentially valuable for elucidating chemico-biological interaction that can be used in the pharmaceuticals, biochemistry and pharmacology arenas.

Pattern, Forms and Bibliometric Analysis for Systematic Study of Silica-Supported Heterogeneous Solar Photocatalyst for Lannate Insecticide Abatement from Aqueous Stream

Agro-industrial streams with high toxic loadings must undergo for treatment prior to final disposal. Thus, the current investigation aimed to apply cheap and naturally available materials to explore sustainable heterogeneous solar/Fenton reaction for insecticide abatement form waste streams. Iron was collected from the wastewater stream after coal industry. The sand pellets were used as iron support material which acts as a heterogeneous solar photo-catalyst like modified Fenton reaction. The prepared catalysts were characterized using X-ray diffraction (XRD) and scanning electron microscope (SEM) for characterization. System parameters variables were studied using the modified catalysts. Although the acidic pH showed maximal removal efficiency, the catalyst could also work at a wide pH range with a reduced activity. The optimum conditions of the newly synthesized modified Fenton composite showed 103, 45 mg/L for H2O2 and catalyst, respectively, at pH 2.8 within 90 min under solar irradiation for maximal Lannate oxidation reached to 98%. Moreover, the increase in Lannate concentration loading results in a reduction in the removal efficiency from 98 to 96% when the Lannate loading increased from 10 to 50 ppm, although further increase of Lannate (100 ppm) results in only 2% removal. Also, temperature effect was displayed and the high temperature range was unfavorable. The kinetics of Lannate removal was dependent on operation temperature and following the first-order kinetic model. The thermodynamic parameters values settled the system is non-spontaneous in nature, proceeds in endothermic circumstances and working in a low energy barrier (34.54 kJ mol−1). Recyclability confirms the sustainability of the catalyst, and the third cycle catalytic use attained 28% Lannate removal.

Sulfate removal by barium-terephthalate MOF synthesized from recycled PET-waste using Doehlert design optimization

In this study, barium-terephthalate metal–organic framework (Ba(BDC)) was synthesized as a new efficient adsorbent by an aqueous media method. Terephthalate ligand recovered from polyethylene terephthalate (PET) waste was used as a precursor in the synthesis process. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), energy-dispersive X-ray (EDX), and field-emission scanning electron microscopy (FESEM) were applied to analyze the chemical and crystal structure of Ba(BDC). For the first time, the adsorption ability of this compound was investigated to remove sulfate ions from water. Experimental design optimization approach involving both screening the effective factors (i.e. pH, adsorbent dosage (m), initial concentration of sulfate ion (C), and temperature (T), except contact time (t)) and running Doehlert design was led to obtaining a regression model for the relation between the removal percent of sulfate ion (R%) and four effective factors as follows.R%=0.366pH-0.01328C+3.641m+0.2589T-0.02248pH2+0.000003C2-0.2991m2-0.003452T2+0.000437pH×C-0.01377pH×T-0.001821C×m+0.000102C×T The resulting model was employed for finding optimum conditions including T = 29 °C, pH = 2, m = 3.1 mg, and C = 200 mg+L−1 that maximize R% of sulfate ion to 99.43 value. Furthermore, kinetics, isotherms, and thermodynamics studies are complementary divisions of this research. Because of a non-linear R2 value closer to 1 (R2 = 0.9831), the Langmuir-Freundlich isotherm model better describes the adsorbent-adsorbate behavior and its maximum adsorption capacity is qmax of 549.5 mg·g−1. The kinetic experimental data obey the pseudo-second-order model (R2 = 0.9984). Based on the negative value of thermodynamic parameters including ΔH°, ΔS°, and ΔG°, the adsorption process is exothermic and spontaneous chemisorption at various temperatures (298, 308, 318, and 328 K).

Biosorption Study of Pb(II) Ions onto Treated Eupatorium adinoforum (AEA) and Acer Oblongum (AAO): Thermodynamic and Equilibrium Studies

In the present study, dried activated biomass of Eupatorium adinoforum (AEA) and Acer oblongum (AAO) used for removal of Pb (II) from synthetic wastewater. The batch operation was conducted with effect of variation of contact time, biosorbent dose, pH, concentration of metal ions and temperature on biosorption of metal ions on biosorbent. Maximum adsorption was recorded for initial metal ion concentration of 10 mg/l, biosorbent dose of 2.5 gm, at pH 5 with 105 minutes of contact time for activated AEA and AAO biomass. The adsorption equilibrium conditions were well described by Langmuir, Freundlich and Temkin isotherm models. The Langmuir isotherm model has provided a better fit with the experimental data in comparison to that of Freundlich and Temkin isotherm models. Thermodynamic data suggest that the bisorption process was spontaneous, feasible and endothermic. The values of thermodynamic parameters suggest that the biosorption process was spontaneous, feasible and endothermic. The kinetics of the biosorption for the reaction mechanism and types of biosorption process onto activated AEA and AAO biosorbent were also discussed.

Best practice for improved accuracy: A critical reassessment of van’t Hoff analysis of melt curves

Biomolecular thermodynamics, particularly for DNA, are frequently determined via van’t Hoff analysis of optically measured melt curves. Accurate and precise values of thermodynamic parameters are essential for the modeling of complex systems involving cooperative effects, such as RNA tertiary structure and DNA origami, because the uncertainties associated with each motif in a folding energy landscape can compound, significantly reducing the power of predictive models. We follow the sources of uncertainty as they propagate through a typical van’t Hoff analysis to derive best practices for melt experiments and subsequent data analysis, assuming perfect signal baseline correction. With appropriately designed experiments and analysis, a van’t Hoff approach can provide surprisingly high precision, e.g., enthalpies may be determined with a precision as low as 10−2 kJ ⋅ mol−1 for an 8-base DNA oligomer.

Facile preparation of amine -functionalized corn husk derived activated carbon for effective removal of selected heavy metals from battery recycling wastewater

In this work, an efficient and eco-friendly amine functionalized corn husk derived activated carbon with high adsorption capacity was prepared and utilized for Pb (II), Cu(II) and Ni(II) ions removal from battery recycling wastewater. The developed adsorbent was characterized to determine the surface morphology, elemental composition, surface chemistry and surface area using SEM/EDS, FTIR and BET techniques. The BET surface area of the corn husk (CH) and amine-functionalized corn husk activated carbon (AF-CHAC) was found to be 92.11 and 442.70 m2/g, respectively. The effect of adsorption variables which includes temperature, pH, contact time, and adsorbent dosage on uptake behaviour were all examined. Langmuir, Freundlich, Harkin-Jura, Elovich, and D–R isotherm models were fitted to the adsorption data. The adsorption of Pb (II), Cu(II), and Ni (II) ions followed a pseudo-second order kinetic and fit well to the Freundlich isotherm, indicating multi-layer adsorption and chemisorption. The maximum adsorption capacity of Pb(II), Cu(II), and Ni(II) ions, was 2.814, 0.724, and 0.337 mg/g, respectively. According to the thermodynamic parameter values, the adsorption process was spontaneous, exothermic, and physical in nature, with an increase in randomness at the adsorbates-adsorbent interaction. The desorption and reusability experiments revealed that the AF-CHAC has a greater potential as an adsorbent, with a removal efficiency of 99 % after three cycles. Overall, the prepared amine functionalized corn husk derived activated carbon has advantages such as ease of preparation, cost effectiveness, and excellent recyclability, as well as high adsorption capacity, providing a new approach for efficiently treating battery recycling wastewater contaminated with heavy metal ions.

Biodegradable cellulose nanocrystals hydrogels for removal of acid red 8 dye from aqueous solutions

Biodegradable cellulose nanocrystals hydrogels (CNCsH) were synthesized from cellulose nanocrystals (CNCs) which were prepared from office wastepaper (OWP) by a chemical crosslinking method using epicholorohydrin (ECH) as a cross-linker. CNCsH were tested for their swelling behavior and biodegradability and the point of zero charge had been determined. The ability of CNCsH for removing the Acid Red 8 (AR8) anionic dye from its aqueous solution was evaluated. The different parameters affecting removal of the dye, such as pH, initial concentration of dye, content of CNCs, temperature and adsorbent dosage were investigated. The optimum conditions for 68% removal efficiency were pH = 1, initial concentration of dye = 10 ppm, contact time = 105 min, CNCs content = 5% and CNCsH dosage = 0.5 g at 30 °C. The adsorption isotherms, kinetics, and thermodynamic parameters have been studied. The results showed an appropriate fit for Langmuir adsorption isotherm and pseudo-second order kinetics model with an adsorption capacity of 17.12 mg/g. According to the obtained values of thermodynamic parameters, the removal of Acid red 8 by CNCs hydrogels was exothermic spontaneous process.

Novel perspective into the interaction behavior study of the cyanidin with human serum albumin-holo transferrin complex: Spectroscopic, calorimetric and molecular modeling approaches

We examined the inducement of an interaction between two carrier proteins, human serum albumin (HSA) and human holo transferrin (HTF) within the presence of cyanidinin the form of binary and ternary systems, which was conducted by different spectroscopic, isothermal titration calorimetric (ITC), and molecular dynamics simulation techniques. The results of fluorescence spectroscopy verified the occurrence of this interaction by displaying the regular quenching of emission spectra of proteins as single and complex forms by cyanidin. Moreover, fluorescence emission suggested that, HSA-cyanidin, HTF-cyanidin and (HSA-HTF) cyanidin complexes follows an static mechanism with the binding constants of 8.81 × 104, 3.40 × 104, and 7.10 × 104 M−1, respectively, which were strongly reflected to moderate the affinity of cyanidin to both single and complex forms of proteins. The measured thermodynamic parameters obtained by ITC, determined the necessity of electrostatic forces for binding of cyanidin to HSA and HTF. Besides, obtaining a negative ΔG0 is indicative of spontaneous mode of binding process in both conditions. The different values of thermodynamic parameters of cyanidin binding to the forms of HSA, HTF and HSA-HTF complex clearly proved the similarity in the type of interaction forces between cyanidin and proteins as single and complex forms with various values. The observed changes in synchronous fluorescence results were related to the micro-environment properties of Tyr and Trp residues. The induced alternations in the secondary construction of both proteins were confirmed through the outcomes of quantitative analysis performed by circular dichroism spectroscopy (CD) techniques. FRET theory was exerted to calculate, the existing distance across the donor and acceptor, which were reported to be 1.85 nm, 1.97 nm, and 1.91 nm for the cases of HSA-cyanidin, HTF-cyanidin and (HSA-HTF) cyanidin complexes, respectively. Molecular displacement and protein–ligand docking simulations confirmed the binding of cyanidin to HSA and HTF through the binary and ternary systems.