Increased request for metal and metal oxide nanoparticles nanoparticles has led to their large-scale production using high-energy methods with various toxic solvents. This cause environmental contamination, thus eco-friendly “green” synthesis methods has become necessary. An alternative way to synthesize metal nanoparticles includes using bioresources, such as plants and plant products, bacteria, fungi, yeast, algae, etc. “Green” synthesis has low toxicity, is safe for human health and environment compared to other methods, meaning it is the best approach for obtaining metal and metal oxide nanoparticles. This review reveals 12 principles of “green” chemistry and examples of biological components suitable for “green” synthesis, as well as modern scientific research of eco-friendly synthesis methods of magnetic and metal nanoparticles. Particularly, using extracts of green tea, fruits, roots, leaves, etc., to obtain Fe₃O₄ NPs. The various precursors as egg white (albumen), leaf and fruit extracts, etc., can be used for the „green” synthesis of spinel magnetic NPs. “Green” nanoparticles are being widely used as antimicrobials, photocatalysts and adsorbents. “Green” magnetic nanoparticles demonstrate low toxicity and high biocompatibility, which allows for their biomedical application, especially for targeted drug delivery, contrast imaging and magnetic hyperthermia applications. The synthesis of silver, gold, platinum and palladium nanoparticles using extracts from fungi, red algae, fruits, etc., has been described.

One of the most important problems of agriculture is finding new methods to increase soil fertility and productivity. The use of fertilizers increases the efficiency of nutrients, however, their uncontrolled use leads to leaching and contamination of the environment. Zeolite is considered a natural element that has no negative environmental effects. Its ion exchange properties are important for plant nutrition due to its cation exchange ability and porosity. Zeolites added to fertilizers give a double result when applied to soil: provide long lasting action of fertilizer (prolongation effect) and prevent nutrient leaching. This article analyzes current literary sources of information on the use of zeolite-based composites as a prolonged action fertilizer in agriculture, as well as their impact on nutrient retention and release into the soil.

TiO2-based nanomaterials are attracting much attention in many areas, such as photocatalysis, photoelectricity, probing, electrochromism, photochromism, etc. They are widely used in paints, polymers, sunscreens, and toothpaste. There are various ways of synthesis that affect the size, shape, and crystallinity of TiO2 nanoparticles. The main methods of obtaining titanium dioxide (with the structure of anatase, rutile or brookite) in the form of spheres, rods, fibers, and tubes include: sol-gel technology, hydrothermal and solvothermal methods, microwave method involving high-frequency electromagnetic waves, template method, electrodeposition, a sonochemical method using ultrasound, chemical and physical vapor deposition, "green" methods, etc. This literature review presents modern scientific results on the production of TiO2 nanoparticles by various methods.

Water and air pollutants pose a significant environmental problem worldwide and photocatalysis is one way to address this global issue. Photocatalytic degradation of toxic substances under the influence of visible electromagnetic radiation is widely used for wastewater treatment. The most promising method of pollutant removal is the use of photocatalysts based on titanium (IV) oxide, which are recognized as one of the most effective due to chemical resistance, non-toxicity and low cost. However, their practical application is limited by the rapid recombination of photogenerated charge carriers and the selective absorption of light in the UV region due to the large width of band gap. To solve this scientific and practical problem, it is necessary to modify the surface, for example, through metallic or nonmetallic doping, in order to increase its photocatalytic activity due to additional absorption in the visible range of the spectrum. This review presents an analysis of current research on ways to increase the efficiency of TiO2-based photocatalysts.

The comparative analysis of atomic structure and morphology of fumed silica nanoparticles prepared under different synthesis conditions has been carried out using TEM, FTIR, quantum chemistry, and low-temperature nitrogen adsorption methods. It has been determined that the structure of amorphous silica nanoparticles is formed by branched chain-like clusters of 0.6 - 2.4 nm in size that correspond to proto-particles or nuclei of nanoparticles. A linear part of the smallest clusters is consisted of two tetrahedra SiO4 with common oxygen atom and oppositely directed vertices. The inter-tetrahedral average angle Si-O-Si is ca. 180 degrees. It has been shown that the textural porosity of fumed silica powder depends on the initial degree of aggregation of nanoparticles. The average mesopores (1 nm < R < 25 nm) volume is in the rage of 0.26 - 0.60 cm(3).g(-1) for materials pretreated at different temperatures. It has been found out that the mean pores radius decreases from 34 nm to 10 nm with decreasing average size of silica nanoparticles. The micropores (R < 1 nm) contribution to the total pore volume is small for all materials (0.003 - 0.029 cm(3).g(-1)).