BITUMENS AND POLYMER BITUMENS - NANODISPERSE SYSTEMS

This work shows the data regarding the elemental and chemical group compositions of the road bitumens. The short characteristic has been shown for the components of the bitumens - the asphaltenes, the resins and the oils. The properties have been described for the bitumens on which they have the direct impact. The description is given for the micellar model of the bitumens from the point of view of the colloid chemistry. The analysis has been performed for the results of the study by other authors for the asphaltenes of a bitumen and an oil. The group chemical compositions are given for the bitumen of the grades BND 50/70, BND 70/100 and BND 100/130 produced by the plants of Kazakhstan. It has been shown that the content of the asphaltenes in them is from 15.8% to 24.3%; in most cases, the content of the asphaltenes is within the range of 20-25%, i.e. the asphaltenes nanoclusters are almost a fourth of the bitumen by weight. The brief description is given for the best known polymers used for the modification of the road bitumen: 1) the reactive polymers Elvaloy 4170 and Elvaloy AM; 2) the polymers of the group SBS - Kraton D 1192A, Calprene 501, SBS L 30-01 A, KUMHO KTR and Butonal NS 198. It is proposed to consider the bitumen and the polymer bitumen as the peculiar nanodisperse systems. The structures are described for the polymer bitumen nanodisperse systems occurring during the modification of the road bitumen with the polymers of the above two groups.

Experimental Data Contributing to the Elusive Surface Charge of Inert Materials in Contact with Aqueous Media

We studied the charging of inert surfaces (polytetrafluoroethylene, i.e., PTFE; graphite; graphene; and hydrophobic silica) using classical colloid chemistry approaches. Potentiometric titrations showed that these surfaces acquired less charge from proton-related reactions than oxide minerals. The data from batch-type titrations for PTFE powder did not show an effect of ionic strength, which was also in contrast with results for classical colloids. In agreement with classical colloids, the electrokinetic results for inert surfaces showed the typical salt level dependence. In some cases, the point of zero net proton charge as determined from mass and tentatively from acid–base titration differed from isoelectric points, which has also been previously observed, for example by Chibowski and co-workers for ice electrolyte interfaces. Finally, we found no evidence for surface contaminations of our PTFE particles before and after immersion in aqueous solutions. Only in the presence of NaCl-containing solutions did cryo-XPS detect oxygen from water. We believe that our low isoelectric points for PTFE were not due to impurities. Moreover, the measured buffering at pH 3 could not be explained by sub-micromolar concentrations of contaminants. The most comprehensive explanation for the various sets of data is that hydroxide ion accumulation occurred at the interfaces between inert surfaces and aqueous solutions.

Laser assisted synthesis of anisotropic metal nanocrystals and strong light-matter coupling in decahedral bimetallic nanocrystals

The advances in colloid chemistry and nanofabrication allowed us to synthesize noble monometallic and bimetallic nanocrystals with tunable optical properties in the visible and near infrared region of the electromagnetic spectrum.

Electrodialysis desalination and limiting concentration of highly mineralized waters

We study the regularities of the process of desalination of sodium chloride solutions with a limiting concentration of 10.2 to 37.7 g/dm3, which simulate chloride wastewater of some mining enterprises. We use an electrodializerconcentrator with advanced design developed at A.V. Dumansky Institute of Colloid Chemistry and Water Chemistry of the NASU. The need to develop such device is caused by the necessity of the deep concentration of concentrates obtained during the wastewater treatment in order to facilitate their further processing into secondary material resources. The electrodialyzers produced by the industry are unsuitable for a significant concentration, since the concentration chambers in such devices and the desalination chambers are pumped with the initial solution. This leads to a significant reduction in the concentration of the resulting brine. Studies have shown that the use of the specified electrodializer-concentrator allowed one to obtain for 100 min from solutions with a concentration of 10.2, 18.8, and 37.7 g/dm3 Cl-ion diluents containing them, respectively, 0.2, 0.6, and 1.0 g/dm3 and to concentrate the brine by 10.6, 6.7, and 4.0 times, respectively. Based on this research and the experience gained at the Institute in the field of mine water treatment, a basic block diagram of the mine water treatment is developed. It is based on a combination of advanced electroodialysis and reverse osmosis. The complex processing of substances removed during the mine water treatment involves their use in relevant industries; additional desalination diluent can be used for technical purposes, and its excess is discharged into reservoirs.