Adsorbaatti

Adsorbaatti, the Finnish term for adsorbate, refers to the species that is adsorbed at an interface, typically a solid surface or a liquid–gas boundary. It can be an atom, molecule, ion or complex and may participate in chemical reactions at the surface or remain physically attached. Adsorption concentrates the adsorbaatti at the interface, arising from intermolecular forces such as van der Waals interactions (physisorption) or chemical bonding (chemisorption). Physisorption is usually reversible and weak, while chemisorption involves stronger bonds and can alter surface structure.

The properties of an adsorbaatti depend on the surface, temperature and ambient environment. Adsorption is commonly described by isotherms. The Langmuir model assumes a finite number of equivalent sites and monolayer coverage, while the Freundlich model is empirical and suitable for heterogeneous surfaces. For porous materials, BET theory extends adsorption to multilayer coverage.

Adsorbaatti plays key roles in catalysis, sensors, environmental remediation and materials science. In heterogeneous catalysis, the rate-determining steps often involve adsorption and desorption of reactants and products. In environmental contexts, adsorbaatti on activated carbon or aluminosilicates remove pollutants from water or air.

Characterization techniques include temperature-programmed desorption, infrared spectroscopy, X-ray photoelectron spectroscopy, scanning probe microscopy and others that probe composition, bonding and coverage at surfaces. Understanding the behavior of adsorbaatti is central to surface science and interface engineering.