Removal of uranium(VI) from aqueous solutions using nanoporous ZnO prepared with microwave-assisted combustion synthesis

The adsorption of the uranyl ions from aqueous solutions on the nanoporous ZnO powders has been investigated under different experimental conditions. The adsorption of uranyl on nanoporous ZnO powders were examined as a function of the contact times, pH of the solution, concentration of uranium(VI) and temperature. The ability of this material to remove U(VI) from aqueous solution was followed by a series of Langmuir and Freunlinch adsorption isotherms. The adsorption percent and distribution coefficient for nanoporous ZnO powders were 98.65 % ± 1.05 and 7,304 mL g^?1, respectively. The optimum conditions were found as at pH 5.0, contact time 1 h, at 1/5 Zn²⁺/urea ratio, 50 ppm U(VI) concentration and 303 K. The monomolecular adsorption capacity of nanoporous ZnO powders for U(VI) was found to be 1,111 mg g^?1 at 303 K. Using the thermodynamic equilibrium constants obtained at different temperatures, various thermodynamic parameters, such as ΔG°, ΔH° and ΔS°, have been calculated. Thermodynamic parameters (ΔH° = 28.1 kJ mol ^?1, ΔS° = 160.30 J mol^?1 K^?1, ΔG° = ?48.54 kJ mol^?1) showed the endothermic and spontaneous of the process. The results suggested that nanoporous ZnO powders was suitable as sorbent material for recovery and adsorption of U(VI) ions from aqueous solutions.     

Immobilisation of lead(II) ions from aqueous solutions on natural coal

The immobilisation of lead(II) ions from aqueous solutions on natural coal was investigated to compare calculated and measured adsorption enthalpies. For this purpose, adsorption isotherms were measured at temperatures of 303, 333 and 353 K. Adsorption enthalpy ΔH was evaluated from temperature dependence of the equilibrium constant of adsorption using the van‘t Hoff equation. Thus, the value of ΔH = 27 kJ mol^?1 was obtained manifesting endothermic effect of lead(II) immobilisation on the coal. However, based on the flow and immersion calorimetric measurements, the exothermic character of lead(II) adsorption on the studied coal was proven with a value of about ?7 kJ mol^?1.     

Kinetic and thermodynamic parameters of volatilization of biodiesel from babassu, palm oil and mineral diesel by thermogravimetric analysis (TG)

The boiling point and volatility are important properties for fuels, as it is for quality control of the industry of petroleum diesel and biofuels. In addition, through the volatility is possible to predict properties, such as vapor pressure, density, latent heat, heat of vaporization, viscosity, and surface tension of biodiesel. From thermogravimetry analysis it is possible to find the kinetic parameters (activation energy, pre-exponential factor, and reaction order), of thermally simulated processes, like volatilization. With the kinetic parameters, it is possible to obtain the thermodynamic parameters by mathematical formula. For the kinetic parameters, the minor values of activation energy were found for mineral diesel (E = 49.38 kJ mol^?1), followed by babassu biodiesel (E = 76.37 kJ mol^?1), and palm biodiesel (E = 87.00 kJ mol^?1). Between the two biofuels studied, the babassu biodiesel has the higher minor value of activation energy. The thermodynamics parameters of babassu biodiesel are, ΔS = ?129.12 J mol^?1 K^?1, ΔH = +80.38 kJ mol^?1 and ΔG = +142.74 kJ mol^?1. For palm biodiesel ΔS = ?119.26 J mol^?1 K^?1, ΔH = + 90.53 kJ mol^?1 and ΔG = +141.21 kJ mol^?1, and for diesel ΔS = ?131.3 J mol^?1 K^?1, ΔH = +53.29 kJ mol^?1 and ΔG = +115.13 kJ mol^?1. The kinetic thermal analysis shows that all E, ΔH, and ΔG values are positive and ΔS values are negative, consequently, all thermodynamic parameters indicate non-spontaneous processes of volatilization for all the fuels studied.     

Sorption study of uranium on carbon spheres hydrothermal synthesized with glucose from aqueous solution

The ability of oxygen-rich carbon spheres (CSs) produced by hydrothermal carbonization with the glucose has been explored for the removal and recovery of uranium from aqueous solutions. The micro-morphology and structure of CSs were characterized by FT-IR and SEM. The influences of different experimental parameters such as solution pH, initial concentration, contact time, ionic strength and temperature on adsorption were investigated. The CSs showed the highest uranium sorption capacity at initial pH of 6.0 and contact time of 25 min. Adsorption kinetics was better described by the pseudo-second-order model and adsorption process could be well defined by the Langmuir isotherm. The thermodynamic parameters, △G°(298 K), △H° and △S° were determined to be ?16.88, 12.09 kJ mol^?1 and 197.87 J mol^?1 K^?1, respectively, which demonstrated the sorption process of CSs towards U(VI) was feasible, spontaneous and endothermic in nature. The adsorbed CSs could be effectively regenerated by 0.05 mol/L HCl solution for the removal and recovery of U(VI). Complete removal (99.9 %) of U(VI) from 1.0 L industry wastewater containing 15.0 mg U(VI) ions was possible with 3.0 g CSs.     

Adsorption of uranium from aqueous solution using biochar produced by hydrothermal carbonization

The ability of biochar produced by hydrothermal carbonization (HTC) has been explored for the removal and recovery of uranium from aqueous solutions. The micro-morphology and structure of HTC were characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. The influences of different experimental parameters such as solution pH, initial concentration, contact time, ionic strength and temperature on adsorption were investigated. The HTC showed the highest uranium sorption capacity at initial pH of 6.0 and contact time of 50 min. Adsorption kinetics was better described by the pseudo-second-order model and adsorption process could be well defined by the Langmuir isotherm. The thermodynamic parameters, △G°(298 K), △H° and △S° were determined to be ?14.4, 36.1 kJ mol^?1 and 169.7 J mol^?1 K^?1, respectively, which demonstrated the sorption process of HTC towards U(VI) was feasible, spontaneous and endothermic in nature. The adsorbed HTC could be effectively regenerated by 0.05 mol/L HCl solution for the removal and recovery of U(VI). Complete removal (99.9 %) of U(VI) from 1.0 L industry wastewater containing 15.0 mg U(VI) ions was possible with 2.0 g HTC.     

A detailed study of isothermal crystallization of As2Se3 undercooled liquid

Isothermal crystallization of an As₂Se₃ undercooled melt was studied by differential scanning calorimetry and described using the classical theory of nucleation and crystal growth. The maximum rate of nucleation and crystal growth was observed to occur at approximately 235 and 350 °C, respectively. The activation energies of nucleation and crystal growth were determined to be ΔE _D = 311 kJ mol^?1 and ΔE* = 104 kJ mol^?1, respectively. The temperature dependencies of both the activation free energy of nucleation, ΔG*, and the critical diameter, r*, were also calculated.     

Thermal studies and spectral characterization of the chelate of bis-(η5-cyclopentadienyl titanium(IV) with salicylidene-4-methylaniline

A new chelate (η⁵-C₅H₅)₂Ti(SB)₂, whereSB=O, N donor Schiff base salicylidene-4-methylaniline, was synthesized. The course of thermal degradation of the chelate was studied by thermogravimetric (TG) and differential thermal analysis (DTA) under dynamic conditions of temperature. The order of the thermal decomposition reaction and energy of activation was calculated from TG curve while from DTA curve the change in enthalpy was calculated. Evaluation of the kinetic parameters was performed by Coats-Redfern as well as Piloyan-Novikova methods which gaven=1, ΔH=1.114 kJ·mol^?1, ΔE=27.01 kJ·mol^?1, ΔS=?340.12 kJ·mol^?1·K^?1 andn=1, ΔH=1.114 kJ·mol^?1, ΔE=20.01 kJ·mol^?1, ΔS=?342.60 kJ·mol^?1·K^?1, respectively. The chelate was also characterized on the basis of different spectral studies viz. conductance, molecular weight, IR, UV-visible and¹H NMR, which enabled to propose an octahedral structure to the chelate.     

Some Thermodynamic Properties of Aqueous 2-Mercaptopyridine-N-Oxide (Pyrithione) Solutions

The thermodynamic properties of 2-mercaptopyridine-N-oxide (pyrithione, PT) were studied potentiometrically in NaCl aqueous solutions at different ionic strengths and temperatures. A set of protonation constants is provided, together with distribution (water/2-methyl-1-propanol) and solubility data. The total and the specific solubility (solubility of neutral species) values of pyrithione were determined and, for example, are 0.0561 and 0.0518 mol·dm^?3 at c _NaCl = 0.244 mol·dm^?3 and T = 298.15 K. By fitting the distribution and solubility results against the ionic strength, the Setschenow coefficient and the activity coefficients of the neutral species were determined. In pure water, the specific solubility is log₁₀ \( S_{m 0}^{0} = \, {-} 1. 20 \, \pm \, 0.0 4 \) . To determine the activity coefficient of the charged species and the protonation constant at infinite dilution, the data were analyzed by different models, namely the Debye–Hückel type equation, the SIT (Specific ion Interaction Theory) and the Pitzer approach. The interaction coefficient of the deprotonated pyrithione species was determined [ε(Na⁺, PT^?) = ?0.105 ± 0.002]. The protonation enthalpy was also determined, is slightly positive, and the protonation process is entropic in nature. At infinite dilution and T = 298.15 K, log₁₀ K ^H0 = 4.620 ± 0.002, ΔG ⁰ = –26.4 ± 0.1 kJ·mol^?1, ΔH ⁰ = 2.1 ± 0.5 kJ·mol^?1 and TΔS ⁰ = 28.5 ± 0.5 kJ·mol^?1. The electrochemical behavior of pyrithione was studied in NaCl solutions at T = 298.15 K. It was found that voltammetry can be used to study the binding ability of pyrithione towards metal cations. The results of this work are in agreement with literature findings and improve the knowledge of the chemistry of pyrithione in aqueous solutions.     

Removal of thorium from aqueous solution by ordered mesoporous carbon CMK-3

The ability of ordered mesoporous carbon CMK-3 has been explored for the removal and recovery of thorium from aqueous solutions. The textural properties of CMK-3 were characterized using small-angle X-ray diffraction and N₂ adsorption–desorption, and the BET specific surface area, pore volume and the pore size were 1143.7 m²/g, 1.10 cm³/g and 3.4 nm. The influences of different experimental parameters such as solution pH, initial concentration, contact time, ionic strength and temperature on adsorption were investigated. The CMK-3 showed the highest thorium sorption capacity at initial pH of 3.0 and contact time of 175 min. Adsorption kinetics was better described by the pseudo-second-order model and adsorption process could be well defined by the Langmuir isotherm. The thermodynamic parameters, △G°(298 K), △H° and △S° were determined to be -0.74 kJ·mol^?1, 9.17 kJ·mol^?1 and 33.24 J·mol^?1·K^?1, respectively, which demonstrated the sorption process of CMK-3 towards Th(IV) was feasible, spontaneous and endothermic in nature. The adsorbed CMK-3 could be effectively regenerated by 0.02 mol/L HCl solution for the removal and recovery of Th(IV).     

Study of the gadolinium sorption on the C100 ion-exchange resin for the development of the antineutrino detector targets

Adsorption of the gadolinium from H₂O and HCl solutions on the ion-exchange resin C100 is investigated. The experiments were carried out by varying the acidity of the liquid phase, the amount of sorbent, and the temperature. The maximal sorption of the ions Gd³⁺ is observed from the solution 0–0.2 M HCl under optimal conditions, the sorption reaches more than 99.5%. Sorption of Gd³⁺ on C100 from H₂O solution occurs most intensively during the first 3 min then for 30 min the system smoothly comes to equilibrium. The maximal sorption capacity of the resin C100 amounted to 1.2 ± 0.1 mmol g^?1. The thermodynamic parameters of sorption: ΔG = ? 24.20 kJ mol^?1, ΔS = ? 90.27 J mol^?1 K^?1, ?H = ? 50.93 kJ mol^?1 were evaluated. It is shown that the sorption of gadolinium on the ion-exchange resin C100 is described by models of kinetically pseudo-first and pseudo-second order. It is established that the Gd³⁺ sorption on the C100 resin is reversible second order chemical reaction.     

Sorption study of uranium from aqueous solution on ordered mesoporous carbon CMK-3

The ability of ordered mesoporous carbon CMK-3 has been explored for the removal and recovery of uraium from aqueous solutions. The textural properties of CMK-3 were characterized using small-angle X-ray diffraction and N₂ adsorption–desorption, and the BET specific surface area, pore volume and the pore size were 1143.7 m²/g, 1.10 cm³/g and 3.4 nm. The influences of different experimental parameters such as solution pH, initial concentration, contact time, ionic strength and temperature on adsorption were investigated. The CMK-3 showed the highest uranium sorption capacity at initial pH of 6.0 and contact time of 35 min. Adsorption kinetics was better described by the pseudo-second-order model and adsorption process could be well defined by the Langmuir and Freundlich isotherm. The thermodynamic parameters, ?G°(298 K), ?H° and ?S° were determined to be ?7.7, 21.5 k J mol^?1 and 98.2 J mol^?1 K^?1, respectively, which demonstrated the sorption process of CMK-3 towards U(VI) was feasible, spontaneous and endothermic in nature. The adsorbed CMK-3 could be effectively regenerated by 0.05 mol/L HCl solution for the removal and recovery of U(VI). Complete removal (99.9 %) of U(VI) from 1.0 L industry wastewater containing 15.0 mg U(VI) ions was possible with 2.0 g CMK-3.     

Mechanism of Oxidation of Ketorolac by Hexacyanoferrate(III) in Aqueous Alkali: A Thermodynamics and Kinetics Study

The kinetics of the oxidation of ketorolac by hexacyanoferrate(III) (HCF) in aqueous alkaline medium at a constant ionic strength of 0.75 mol·dm^?3 was studied spectrophotometrically at 300 K. A plausible mechanism was proposed and the rate law was derived. The mechanism of oxidation of ketorolac (KET) in alkaline medium has been shown to proceed via a KET-HCF complex, which decomposes in a slow step followed by other fast steps to give the products. The main oxidative product was identified as (2,3-dihydro-1-hydroxy-1H-pyrrolizin-5-yl-)(phenyl)methanone and is characterized by its LC–ESI–MS spectrum. Thermodynamic parameters of various equilibria of the mechanism were calculated and activation parameters ΔH ^≠, ΔS ^≠, ΔG ^≠ and log₁₀ A were found to be 29.9 kJ·mol^?1, ?220 J·K^?1·mol^?1, 96 kJ·mol^?1 and 2.70 respectively.     

Drug–tea polyphenol interaction

Propericiazine (PCZ) is an antipsychotic agent used for the treatment and the prevention of relapse of schizophrenia. We found that when an oral solution containing PCZ was mixed with a green tea drink, the residual content of PCZ was reduced by forming an insoluble complex between PCZ and tea polyphenol. In this study, the mechanism underlying the incompatibility of PCZ with green tea polyphenol (GTP) in the solution was clarified by isothermal titration microcalorimetry (ITC). Both solutions of 27.4 mM PCZ and 2.2 mM (?)-epigallocatechin gallate (EGCg), which is a main ingredient of GTP, were mixed and then PCZ in the filtrate was reduced to approximately 60 %. According to measurement at 298 K by ITC, PCZ formed an insoluble complex with EGCg at an associate constant (K) of 4.75 × 10² M^?1 exothermically, ΔH = ?40.0 kJ mol^?1. When (?)-epicatechin gallate (ECg) was used as the GTP, PCZ interacted with ECg with K and ΔH values of 3.74 × 10² M^?1 and ?22.1 kJ mol^?1, respectively. On the other hand, little heat of the reaction between PCZ and (?)-epigallocatechin or (?)-epicatechin was observed. The results indicated that the main reason for this incompatibility was the formation of an insoluble complex by PCZ and a gallate-type GTP such as EGCg and ECg in the aqueous solution.     

Insight from adsorption properties of Xylidyl Blue embedded hydrogel for effective removal of uranyl: Experimental and theoretical approaches

Applications of a hybrid material consisting of polyacrylamide (PAA) and Xylidyl Blue (XB) for the removal of uranyl ions from aqueous solutions has been investigated with all details. Adsorption experiments were performed at batch mode and constant temperature. Experimental parameters affecting adsorption process such as pH, initial uranyl concentration, time and temperature were studied on the removal of the uranyl ions. The isotherms assays were carried out with synthetic solutions and adsorption data were evaluated by using Langmuir, Freundlich and Dubinin–Radushkevich (D–R) isotherm models. Morphological and chemical characterizations of new synthesized material were investigated by UV-VIS-NIR spectroscopy and SEM/EDX techniques and pH_pzc experiments. The results of the kinetic experiments are consistent with pseudo-second-order models and intra-particle diffusion models with a slightly better fit to the latter. Equilibrium was achieved within 3 h. The value of rate constant for adsorption process was calculated as 1.055 mol⁻¹ kg min⁻¹ at 318 K. The calculated thermodynamic parameters (ΔG°, ΔH° and ΔS°) indicated that the adsorption of uranyl ions onto XB@PAA was feasible, spontaneous and endothermic nature under the studied temperature. The developed material has also a potential as a sensor because its color turn from pink to red by adsorption of uranyl ions.     

Dibenzofuran and methyldibenzofuran derivatives: assessment of thermochemical data

Thermochemical data of dibenzofuran, a compound of considerable industrial and environmental significance, obtained from experimental calorimetric and computational techniques are reported in this work. The enthalpy of fusion, (19.4 ± 1.0) kJ mol^?1, at the temperature of fusion, (355.52 ± 0.02) K, was determined by differential scanning calorimetry measurements of dibenzofuran. From the standard (p° = 0.1 MPa) molar enthalpies of formation of crystalline dibenzofuran, (?29.2 ± 3.8) kJ mol^?1, and of sublimation, (84.5 ± 1.0) kJ mol^?1, determined at T = 298.15 K by static bomb combustion calorimetry and by vacuum drop microcalorimetry, respectively, it was possible to calculate the enthalpy of formation of the gaseous compound, (55.0 ± 3.9) kJ mol^?1, at the same temperature. The enthalpy of formation in the gaseous phase was also determined from G3(MP2)//B3LYP calculations. The same computational strategy was employed in the calculation of the standard molar enthalpies of formation, at T = 298.15 K, in the gas-phase, of single methylated derivatives of benzofuran and dibenzofuran.     

Experimental and theoretical evidence suggests carbamate intermediates play a key role in CO2 sequestration catalysed by sterically hindered amines

The chemisorption of CO₂ by aqueous-hindered amines has been investigated experimentally and theoretically. Negative-ion ESI–MS analysis of solutions containing a sterically hindered amine and a source of ¹³CO₂ reveals peaks corresponding to [M–H + 45]^?. These ions readily lose 45 Da when subjected to collisional activation, and together with other key fragments confirms the generation of the ¹³C-labelled carbamate derivatives. The thermochemistry of the two key capture reactions: $$2.{\text{amine }} + {\text{ CO}}_{ 2} { \leftrightarrows }{\text{amine}} - {\text{CO}}_{ 2}^{ - } + {\text{ amine}} - {\text{H}}^{ + } {\kern 1pt} \quad 1:{\text{carbam}}$$ $${\text{amine }} + {\text{ CO}}_{ 2} + {\text{ H}}_{ 2} {\text{O}}{ \leftrightarrows }{\text{HCO}}_{ 3}^{ - } + {\text{ amine}} - {\text{H}}^{ + } \quad 2:{\text{ bicarb}}$$ at 298 K was modelled using composite chemistry methods, CCSD(T), DFT, and SM8 free energies of solvation. The aqueous reaction free energies (ΔG ₂₉₈) for reaction 1 are predicted to be more negative than ΔG ₂₉₈ for reaction 2 when amine = ammonia, 2-aminoethanol (MEA), 2-amino-2-methyl-1-propanol (AMP), 2-amino-2-hydroxymethyl-propane-1,3-diol (tris), and 2-piperidinemethanol (2-PM). For AMP, tris, and 2-PM, activation free energies ΔG ₂₉₈ ^? for reaction 1 (SM8 + CCSD(T)/6-311 ++G(d,p)//M08-HX/MG3S: 38–67 kJ mol^?1) are smaller than the corresponding values for 2 (109–113 kJ mol^?1). For 2-PM, the computed carbamate ΔG ₂₉₈ ^? (38 kJ mol^?1) is comparable to the MEA value (45 kJ mol^?1), whereas the primary amines with tertiary alpha carbons have slightly larger values (60–70 kJ mol^?1). The organic amine values are much lower than the value for ammonia (93 kJ mol^?1). The results indicate CO₂ chemisorption proceeds via a carbamate intermediate for all aqueous primary and secondary amines. Hindered carbamates are susceptible to further chemical transformations following their formation.     

Chromatographic Framework to Determine the Memantine Binding Mechanism on Human Serum Albumin Surface

In this work, the interaction of memantine with human serum albumin (HSA) immobilized on porous silica particles was studied using a biochromatographic approach. The determination of the enthalpy change at different pH values suggested that the protonated group in the memantine–HSA complex exhibits a heat protonation with a magnitude around 65 kJ mol^?1. This value agrees with the protonation of a guanidinium group, and confirmed that an arginine group may become protonated in the memantine–HSA complex formation. The thermodynamic data showed that memantine–HSA binding, for low temperature (<293 K), is dominated by a positive entropy change. This result suggests that dehydration at the binding interface and charge–charge interactions contribute to the memantine–HSA complex formation. Above 293 K, the thermodynamic data ΔH and ΔS became negative due to van der Waals interactions and hydrogen bonding which are engaged at the complex interface. The temperature dependence of the free energy of binding is weak because of the enthalpy–entropy compensation caused by a large heat capacity change, ΔC _p = ? 3.79 kJ mol^?1 K^?1 at pH = 7. These results were used to determine the potential binding site of this drug on HSA.     

Low-temperature heat capacities, and thermodynamic properties of solid–solid phase change material bis(1-octylammonium) tetrachlorocuprate

A new crystalline complex (C₈H₁₇NH₃)₂CuCl₄(s) (abbreviated as C₈Cu(s)) was synthesized by liquid phase reaction. Chemical analysis, elemental analysis, and X-ray crystallography were applied to characterize the composition and crystal structure of the complex. Low-temperature heat capacities of the complex were measured by a precision automatic adiabatic calorimeter over the temperatures ranging from 78 to 395 K, and two solid–solid phase changes appeared in the heat capacity curve. The temperatures, molar enthalpies and entropies of the two phase transitions of the complex were determined to be: T _{trs, 1} = 309.4 ± 0.35 K, Δ_trs H _{m, 1} = 16.55 ± 0.41 kJ mol^?1, and Δ_trs S _{m, 1} = 53.49 ± 1.3 J K^?1 mol^?1 for the first peak; T _{trs, 2} = 338.5 ± 0.63 K, Δ_trs H _{m, 2} = 6.500 ± 0.10 kJ mol^?1, and Δ_trs S _{m, 2} = 19.20 ± 0.28 J K^?1 mol^?1 for the second peak. Two polynomial equations of the heat capacities as a function of the temperature were fitted by least-square method. Smoothed heat capacities and thermodynamic functions of the complex relative to the standard reference temperature of 298.15 K were calculated based on the fitted polynomial equations.     

Electrochemistry of Interaction Between Flavin Mononucleotide (FMN) and PM-17 as Antitumoral ε-Keggin Core Compound, \left[ {{\text{H}}_{ 2} {\text{Mo}}_{ 1 2}^{\text{V}} {\text{O}}_{ 2 8} \left( {\text{OH}} \right)_{ 1 2} \left( {{\text{Mo}}^{\text{VI}} {\text{O}}_{ 3} } \right)_{ 4} } \right]^{ 6- } at pH 7.5

In order to obtain a clue to the antitumor mechanism of $\left[ {{\text{Me}}_{ 3} {\text{NH}}} \right]_{ 6} \left[ {{\text{H}}_{ 2} {\text{Mo}}_{ 1 2}^{\text{V}} {\text{O}}_{ 2 8} \left( {\text{OH}} \right)_{ 1 2} \left( {{\text{Mo}}^{\text{VI}} {\text{O}}_{ 3} } \right)_{ 4} } \right]$ ·2H₂O (PM-17), the interaction of PM-17 with flavin mononucleotide (FMN) as a prosthetic group of the flavoprotein has been investigated by both polarographic analysis and isothermal titration calorimetry (ITC) technique at the physiological solution pH (7.5). The half-wave potential (?0.50 V vs. Ag/AgCl) of the d.c. polarogram for the quasi-reversible one-electron reduction of FMN was shifted by PM-17 toward a more positive potential with a resultant deviation from one-electron reduction to formally more than one-electron reduction waves. The PM-17 effect on the d.c. polarogram could be explained by a variety of FMN···(PM-17)_n (n > 0) aggregates with multiple conformations which was supported by the thermodynamic parameters (ΔH = ?29.7 kJ mol^?1, ΔS = ?28.2 J mol^?1 K^?1, ΔG = ?21.5 kJ mol^?1, and number of FMN in the binding with PM-17 (N) = 0.053 at 20 °C) estimated by the ITC technique. A large conformational change of the FMN domain by the FMN···(PM-17)_n aggregates is suggested to prevent the movement of the FMN centers into close proximity with nicotinamide adenine dinucleotide (NADH) with a resultant depression of the electron transport in NADH dehydrogenase.