Due to its inert nature, microplastics accumulate in the water environment, air and soil and are also found in organisms, including humans. Heavy metals, organic pollutants and antibiotics can be adsorbed on the surface of microplastics. The adsorption of substances onto microplastics is influenced by the properties of microplastics, the adsorbate and the adsorption environment. Microplastics pose a threat to organisms and humans, as they carry many additives and toxic substances into the body due to their small size and large surface-to-volume ratio.
To know the properties and impact of microplastics, its characterization is key. The purpose of this thesis is to review recent literature in the field of microplastic characterization and its impact on the environment and organisms. The results of the studies showed that the properties of microplastics (surface properties, reactivity, size) change due to the influence of environmental conditions. Microplastics consisting of polymers with more reactive functional groups (chloride ion, phenyl and amide functional group) and microplastics with an aged surface have higher adsorption capacity. Microplastics also represent a suitable substrate for formation and growth of biofilms.
Before characterization, the sample must be prepared and the microplastics should be separated from other materials in the sample. Different methods of separation (filtration, density separation, etc.) and sample digestion (acid, alkaline, oxidation, enzyme digestion) can be used. Physical characterization is used to determine the size, shape, colour and surface properties. Particles are observed with the naked eye and optical and electron microscopes. Chemical characterization, on the other hand, is used to determine chemical structure, functional groups, overall structure and degree of polymerization. The most commonly use methods of chemical characterization are Fourier transform infrared and Raman spectroscopy, thermal analysis, mass spectroscopy, energy-dispersive spectroscopy and nuclear magnetic resonance. The combination of physical and chemical characterization methods allows us to fully determine physical and chemical properties of microplastics. Knowing these properties allows us to predict its behaviour in the environment.
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