. In the present research, hybrid (AgCl, Ag)NPs/diatomite composites were synthesized by direct impregnation with aqueous silver nitrate solutions. The silver chloride nanoparticles (AgCl-NPs) were formed as an effect of the exchange reaction when silver interacted with the diatomite mineral impurity halite. Nanoparticles of metallic silver (AgNPs) were created by the reduction of silver ions under the influence of hydrogen peroxide. The content of silver chloride nanoparticles in the (AgCl, Ag)NPs/diatomite composite was limited by the content of the halite in the used diatomite. Samples of natural diatomite and synthesized (AgCl, Ag)NPs/diatomite composites were examined by using scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction, infrared spectroscopy and thermogravimetric analysis. Moreover, the antibacterial potential of synthesized composites was also studied using the MIC (minimal inhibitory concentration) method against the most common drug-resistant microorganisms in the medical field: Gram-positive Staphylococcus aureus and Gram-negative Klebsiella pneumoniae. The obtained hybrid (AgCl, AgNPs)/diatomite composites were shown to have antimicrobial potential. However, widespread use requires further study by using various microorganisms and additional cytotoxic studies on eukaryotic systems, e.g., cell lines and animal models.

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In this study, a nanocomposite based on kaolin from the Alekseevsky deposit (Kazakhstan), containing nano-silver particles, was synthesized. Kaolin has good physical and chemical properties and is an effective carrier for medicines. The synthesis of AgNPs/kaolin nanocomposites was carried out by chemical reduction. Impregnation of silver nanoparticles into silica matrix can prevent the agglomeration of mobile ions, and thereby preserve the antibacterial activity of the compound. The composition and structure of the resulting nanocomposite were studied using SEM/EDS analysis to study the morphology and elemental composition of natural and silver-modified kaolin, the specific surface was determined by the BET method, and functional groups were identified by IR spectroscopy. The resulting composite was tested for antibacterial activity against Gram-negative and Gram-positive bacteria (E.Сoli, S. Aureus).

The purpose of the study is to obtain nanofilms based on clay minerals and to study the antibacterial activity of the obtained nanocomposite coatings. Diatomite and kaolin were pretreated with sulfuric acid. Silicon plates were used as model substrates. For the first time, multilayers of the composition diatomite/PAA and kaolin/PAA were obtained by multilayer assembly. In the multi-layer, the antiseptic chlorhexidine was introduced, which plays the role of an antibacterial agent. Scanning electron microscopy (SEM) determined the distribution and thickness of the obtained multi-layer, the elemental composition of nanofilms was determined by the SEM-EDX method. The specific surface of natural and sulfuric acidmodified diatomite and kaolin was examined by the BET method. The wetting angle was determined by the lying drop method. Obtaining coatings on the surface of implantable systems is one of the promising areas in modern medicine. In this regard, the production of nanocovers with antibacterial properties is an urgent issue in the fight against infectious diseases associated with bacterial growth. One of the modern methods for producing nanofilms currently used is the Layer by Layer (LBL) method. Nanofilms obtained by this method have found application in tissue engineering and dressings. The feature of this study is the use of clay minerals such as diatomite of the Mugodzharsky deposit and kaolin of the Alekseevsky deposit, which are concentrated in the west and north of Kazakhstan. The obtained multilayers were used as carriers for chlorhexidine and their antibacterial activity was studied. Nanofilms of diatomite/PAA/chlorhexidine and kaolin/PAA/chlorhexidine were tested against the Escherichia coli (E.coli) gram-negative bacterium. Thus, the obtained nanocomposite coatings based on kaolin and diatomite can be potential carriers for drugs.

THERMAL ANALYSIS OF CALCIUM PHOSPHATES DEPOSITED FROM WATER SOLUTIONS OF HYDROMONOPHOSPHATE AND SODIUM DIPHOSPHATE