Based on the Raman spectra and quantum chemical simulation, the structure of the [Pb(thio)2(mono-ac)2] coordination compound of lead acetate with thiocarbamide is found. It is shown that use of this compound in a water solution for the precipitation of polycrystalline films by aerosol spray pyrolysis (ASP) leads to the formation of a single-phase film of lead sulfide without impurity phases.

Исследованы изотермы адсорбции l-аминокислот на углеродных наночастицах. Выявлена максимальная адсорбция l-аминокислот на углеродных нанотрубках. Установлено, что изотермы адсорбции l-аминокислоты не имеют перегиба, имеют 1 плато, и, по классификации Брунауэра относятся к I типу изотерм адсорбции, следовательно, можно говорить о мономолекулярной сорбции. Предположительно, исследуемые аминокислоты адсорбируются конечными участками нанотрубок.

A relationship between adsorption layer structure at different stages of sorbent filling, hydrophilicity, and spatial orientation of saponin in chitosan phase is revealed by joint analysis of the kinetic curves of saponin sorption, IR spectra of chitosan and saponin samples, and computer-simulation data. The sorbent–sorbate complex is formed due to electrostatic interactions between protonated amino groups in chitosan and carboanions of glucuronic acid in saponin, as well as hydrogen bonding between NH 2 and OH groups in chitosan molecules and OH groups in the carbohydrate moiety of saponin molecules.

Sorption isotherms for L- and D-alanine from aqueous solutions on carbon nanotubes MKN-SWCNT-S1 were constructed. It was found that the sorption of D-alanine on the investigated carbon nanotubes (CNTs) is stronger than the sorption of L-alanine. The difference in sorption can serve as the basis for their separation. The quantum chemical calculation carried out in the frame of density functional theory with dispersion corrections showed a difference in the orientation of the L- and D-alanines relative to CNTs in the adsorption process. This difference leads to a greater number of D amino acid molecules adsorbed on CNT than L-alanine on the same nanotube surface.

The adsorption of ethylene glycol by carbon nanoparticles is studied. Carbon nanoparticles with the highest affinity to ethylene glycol are identified, and an adsorption isotherm is constructed. Based on quantum chemical calculations of the energies of interaction between the sorbate and nanotubes with (4,4) and (6,6) chirality, a change in mechanism is revealed upon the monomolecular adsorption of ethylene glycol on carbon nanotubes, and the adsorption isotherm is thus interpreted.

A computer simulation of complexes of (6,6) open carbon nanotubes (CNTs) with neutral molecules, zwitterions and glycine, alanine, and phenylalanine amino acid anions is performed. In starting structures amino acids are arranged in three types: on the external side face, the open end, and inside CNT. The structure is optimized within the density functional theory with regard to the GD3 dispersion correction with and without taking into account solvation effects. It is found that the greatest CNT–amino acid interaction occurs in the neutral aqueous medium at dissociative chemisorption of the zwitterion (adsorption energy 80-90 kcal/mol) and in the basic medium at anion chemisorption (energy ~48-50 kcal/mol) on the open CNT end.

To separate salts of metals and non-electrolytes, the approach of dialysis through the composite membranes (CMs) is proposed. CM is a combination of cation and anion exchange areas. In the composite membrane, cations and anions are transferred through the respective exchange areas simultaneously without violation of macroscopic electro-neutrality. This provides a better transfer of salts than conventional ion exchange membranes (IEMs). The dialysis of the ethylene glycol aqueous salt solutions through the CMs was investigated. We have shown that the transport of salts through the composite membranes is more intensive (unlike IEM providing no transfer of salts from weakly mineralized aqueous solutions due to the Donnan exclusion) and the ethylene glycol transfer is not very significant, that is the basis of effective separation. The possibility to use of composite membranes for metal salt and other electrolyte separation is discussed.

The structure formed in a sorbent during the super-equivalent sorption of glycine by cation exchanger KU-2-8 is optimized via quantum chemical simulation. The differential thermodynamic characteristics of ion exchange and super-equivalent sorption in the studied system are calculated using a thermodynamic approach that allows us to describe the simultaneous exchange and super-equivalent sorption of compounds by ion-exchangers.

Structure, electric and adsorption properties of carbon open-end nanotubes of (6,6) chirality consisting of 5–19 segments were studied by quantum-chemical methods AM1, PM3, LSDA/3-21G, B3LYP/6-31G. The size effects and adsorption properties of nanotubes are discussed.

By means of computer modeling, the main regularities of the interaction of triterpene saponins with chitosan are revealed. It is shown that the sorption of glycosides changes the ordered configuration of chitosan, and the complex of chitosan with saponin, the derivative of quillaic acid, is more stable than the complex with the derivative of oleanolic acid. The formation of complexes occurs due to electrostatic, hydrophobic interactions, and hydrogen bonds, whose strength is determined by the nature, geometry, and specific structure of terpenes of the β-amyrin series.

The structure and electrical properties of open carbon nanotube with chirality (4,4), consisting of 5-15 segments, are calculated within four quantum chemical models: AM1, PM3, LSDA/3-21G*, and B3LYP/631G. Size effects and the effect of the model choice on the geometry, energy, enthalpy and Gibbs energy of the formation (atomization), Mulliken atomic charges, polarizability, and predicted adsorption properties of nanotubes are discussed.

The paint corrosion protection mechanism has been studied by density functional B3LYPGD3/6-31G(d,p) method using Gaussian09 program. The quantum-chemical study demonstrates the growth of anti-corrosion paint properties by the addition of carbon nanotubes (CNT) in the coating composition. Quantum chemical calculations have shown that the carbon nanotubes have a high affinity to the particles that support corrosion process (anions, oxygen molecules, hydroxyl groups). Thus, CNTs act as the adsorbents of particles that support the corrosion process. (C) 2016 Elsevier B.V. All rights reserved.

By quantum chemistry and molecular dynamics analysis of the structure and chemical bond energy of the hydrated ion pair in a sulfonated cation exchange membrane, hydrogen bonding has been shown to play the determining role in electrically driven membrane transport in systems of this kind. The characteristics of hydrogen bridges linking hydrate water molecules in the sulfonated cation exchange membrane have been studied using the molecular dynamics method.

A quantum chemical and molecular dynamics simulation of a fragment of the sulfo cation exchanger in the form of glycine is performed. It is found that in the system studied an ionic pair dissociates.

Computer simulation of molecular structures in the nicotinic acid-water and nicotinic acid-water-poly(N-vinylpyrrolidone) systems was performed, and the IR spectra of these systems were calculated. The theoretical and experimental IR spectra were compared. Parameters of hydrogen bonds in the studied systems were calculated.

A method is proposed for the determination of the structure of supramolecular systems based on spectrum-structure correlations and quantum-chemical and molecular dynamic modeling. Application of the developed approach to the analysis of the structures carboxy- and sulfo-cation exchangers as alkali metal salts and an amino acid (glycine) suggests that the ion pairs in the studied systems are dissociated. This allows a conclusion that the retention of ions in the ion exchangers in chromatographic separation is due to not only the electrostatic interaction of the fixed and mobile ions, but also hydrogen bonding between the hydration shells of the counterions.