In this paper, we report methods for correction of selectivity of sorbents based on N-(2-sulfoethyl)chitosan towards platinum(IV) and palladium(II) in HCl solutions. The common method for correction of selectivity of the sorbents is variation of their modification degree with complexing groups. An increase in the degree of sulfoethylation of the chitosan leads to the significant increase in selectivity of sorption of palladium(II) over platinum(IV). Application of the N-(2-sulfoethyl)chitosan with the highest degree of sulfoethylation allows for selective separation palladium(II) from platinum(IV) (рН = 5.0). Palladium is quantitatively desorbed from the surface of the N-(2-sulfoethyl)chitosans by 3.5 mol/dm3 solution of HCl. 相似文献
The article substantiates that the transformation of the world economy associated with Industry 4.0 leads to a significant change in the way resources are used and affects the possibility of implementing the concept of sustainable development. In this regard, a combined analysis of the concept of new industrial development and the concept of sustainable development, as well as an assessment of the current practice of their implementation is required. In this paper, such an analysis was carried out on the example of water resources management. The paper proposes a methodology for assessing the correlation of water management and industrial development levels of regions. This includes the use of both traditional statistical approaches to the analysis of the level of development of economic systems, and elements of data mining. The neural network is constructed in order to estimate the forecasted values of the water intensity of the gross regional product when the indicators of the level of industrial development of the regions change. The results show that the most significant indicators for changing water intensity include advanced production technologies used, the share of value-added to high-tech industries, and innovative activities of organisations.
A numerical scheme is developed to simulate a flow around airfoils by using vortex methods. For this scheme, a numerical algorithm is constructed and exact analytical expressions are obtained for the coefficients of a system of linear algebraic equations. For some test problems, it is shown that the developed scheme allows us to solve a wider class of problems and provides much more accurate results in comparison with the known approaches. 相似文献
The scope of work is to study the mutual influence of metal ions during their sorption by sulfoethylated chitosan. The sorption isotherms of metal ions from single- and multi-component solutions are obtained. The sorption capacity of the sorbent towards Ag(I) and Cu(II) is revealed to be 1.63 and 1.41 mmol/g in single-, and 1.40 and 0.85 mmol/g in five-component solution. By comparing the affinity parameter and capacity of sulfoethylated chitosan towards ions in single- and multi-component solutions, it is concluded that Ag(I) and Cu(II) ions suppress the sorption of cobalt(II), nickel(II), zinc(II), cadmium(II), magnesium(II), calcium(II), strontium(II), barium(II), manganese(II) and lead(II). 相似文献
A much more efficient formation of crosslinks was observed in the free‐radical polymerization of dodecyl methacrylate with respect to the amount of decomposed peroxide than it would correspond to the additional peroxide crosslinking of formed poly(dodecyl methacrylate). Polymer crosslinking also proceeds after using 2,2´‐azoisobutyronitrile as initiator of the polymerization of dodecyl methacrylate, although with a substantially lower efficiency compared to the initiation by peroxide under comparable conditions. The efficient formation of crosslinked structures can be explained by branching and copolymerization of monomer with multifunctional dead polymer. Multifunctionality of the formed macromolecules is a result of transfer and addition reactions of the present free radicals with the formed polymer. The difference in the influence of the initiator follows from the higher reactivity of oxy radicals in transfer reactions with monomer dodecyl methacrylate which results in a greater number of polymerizable double bonds built in the polymer chain. 相似文献
A new procedure for the aerobic oxidation of α‐amino acids acylated by pyrrole‐carboxylic acid with triplet dioxygen is introduced. The reaction is general for a variety of pyrrole‐amino acid derivatives and represents a very practical and controllable method for the selective preparation of α‐hydroperoxy‐ or α‐hydroxy‐α‐amino acid diketopiperazines with molecular dioxygen. Furthermore, the non‐catalyzed direct oxidation of amino acid derivatives at the α‐position with molecular dioxygen represents a fundamental question. 相似文献