Studies of Adsorption from Gaseous and Liquid Mixtures on Solids of Quasi-Gaussian Energy Distribution

Previous research6-9 has shown that the Toth equation describes well the adsorption of hydrocarbons on carbon adsorbents, especially on Nuxit-Al charcoal. This fact is probably connected with the quasi-gaussian energy distribution function, which is related to T6th\u27s equation. In this paper, the parameters of the above mentioned equation have been discussed once again and recent results on this subject were taken into account. The modified Toth equation has also been generalized for the case of adsorption from multicomponent gas and liquid mixtures on solids of quasi- gaussian energy distribution

Graphitic Carbon Nitride Nanosheet-Carbon Nanotube Three-Dimensional Porous Composites as High-Performance Oxygen Evolution Electrocatalysts

Australian Research Council (ARC). Grant Numbers: DP140104062, DP13010445

Yolk-Shell-Structured Aluminum Phenylphosphonate Microspheres with Anionic Core and Cationic Shell

Spherical materials with yolk-shell structure have great potential for a wide range of applications. The main advantage of the yolk-shell geometry is the possibility of introducing different chemical or physical properties within a single particle. Here, a one-step hydrothermal synthesis route for fabricating amphoteric yolk-shell structured aluminum phenylphosphonate microspheres using urea as the precipitant is proposed. The resulting microspheres display 3D sphere-in-sphere architecture with anionic core and cationic shell. The controllable synthesis of aluminum phosphates with various morphologies is also demonstrated. The anionic core and cationic shell of the aluminum phenylphosphonate microspheres provide docking sites for selective adsorption of both cationic methylene blue and anionic binuclear cobalt phthalocyanine ammonium sulphonate. These new adsorbents can be used for simultaneous capture of both cations and anions from a solution, which make them very attractive for various applications such as environmental remediation of contaminated water

Theoretical basis for the Dubinin-Radushkevitch (D-R) adsorption isotherm equation

The Dubinin-Radushkevitch (D-R) equation, which was originally proposed as an empirical adaptation The Polanyi adsorption potential theory, has been the fundamental equation to quantitatively describe the adsorption gases and vapors by microporous sorbents. The equation, based on the postulate that the mechanism for adsorption in micropores is that of pore-filling rather than layer-by-layer surface coverage, generally applies well to adsorption systems involving only van der Waals forces and is especially useful to describe adsorption on activated ???. The ability of the D-R equation to describe gas adsorption on porous materials has inspired many to undertake studies, both experimental and theoretical, to explain the source of the success of the D-R equation in ??? of molecular properties at the gas-solid interface. In many cases, these studies have led to extensions or modifications of the original D-R equation. Many of these attempts and the resulting extensions are reviewed and discussed here. Recently, an isotherm equation was derived for adsorption of gases and vapors on microporous ??? from statistical mechanical principles. It was shown that the D-R equation is an approximated form of this potential theory isotherm. This development is also reviewed and discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43972/1/10450_2005_Article_BF01650130.pd

The sol-gel method for preparation of polysiloxane xerogels containing carboxylic functionality

A procedure has been developed for synthesis of new polysiloxane xerogels with propionic and butyric acid-type groups. The procedure is based on the sol-gel method and involves the conversion of 2-cyanoethyltriethoxysilane (or 4-(triethoxysilyl)butyronitrile) to an ester with its subsequent hydrolytic polycondensation reaction.Розроблена методика синтезу нових полісилоксанових ксерогелів, що містять залишки пропіонової і масляної кислот.Разработана методика синтеза новых полисилоксановых ксерогелей, содержащих остатки пропионовой и масляной кислот

Engineering surface atomic structure of single-crystal cobalt (II) oxide nanorods for superior electrocatalysis

Engineering the surface structure at the atomic level can be used to precisely and effectively manipulate the reactivity and durability of catalysts. Here we report tuning of the atomic structure of one-dimensional single-crystal cobalt (II) oxide (CoO) nanorods by creating oxygen vacancies on pyramidal nanofacets. These CoO nanorods exhibit superior catalytic activity and durability towards oxygen reduction/evolution reactions. The combined experimental studies, microscopic and spectroscopic characterization, and density functional theory calculations reveal that the origins of the electrochemical activity of single-crystal CoO nanorods are in the oxygen vacancies that can be readily created on the oxygen-terminated {111} nanofacets, which favourably affect the electronic structure of CoO, assuring a rapid charge transfer and optimal adsorption energies for intermediates of oxygen reduction/evolution reactions. These results show that the surface atomic structure engineering is important for the fabrication of efficient and durable electrocatalysts.Tao Ling, Dong-Yang Yan, Yan Jiao, Hui Wang, Yao Zheng, Xueli Zheng, Jing Mao, Xi-Wen Du, Zhenpeng Hu, Mietek Jaroniec, Shi-Zhang Qia

Influence of Nanoparticle Size and Shape on Oligomer Formation of an Amyloidogenic Peptide

Understanding the influence of macromolecular crowding and nanoparticles on the formation of in-register $\beta$-sheets, the primary structural component of amyloid fibrils, is a first step towards describing \emph{in vivo} protein aggregation and interactions between synthetic materials and proteins. Using all atom molecular simulations in implicit solvent we illustrate the effects of nanoparticle size, shape, and volume fraction on oligomer formation of an amyloidogenic peptide from the transthyretin protein. Surprisingly, we find that inert spherical crowding particles destabilize in-register $\beta$-sheets formed by dimers while stabilizing $\beta$-sheets comprised of trimers and tetramers. As the radius of the nanoparticle increases crowding effects decrease, implying smaller crowding particles have the largest influence on the earliest amyloid species. We explain these results using a theory based on the depletion effect. Finally, we show that spherocylindrical crowders destabilize the ordered $\beta$-sheet dimer to a greater extent than spherical crowders, which underscores the influence of nanoparticle shape on protein aggregation

Numerical study of multilayer adsorption on fractal surfaces

We report a numerical study of van der Waals adsoprtion and capillary condensation effects on self-similar fractal surfaces. An assembly of uncoupled spherical pores with a power-law distributin of radii is used to model fractal surfaces with adjustable dimensions. We find that the commonly used fractal Frankel-Halsey-Hill equation systematically fails to give the correct dimension due to crossover effects, consistent with the findings of recent experiments. The effects of pore coupling and curvature dependent surface tension were also studied.Comment: 11 pages, 3 figure