adsorvendo

Adsorbing, or adsorption, is the adhesion of atoms, ions, or molecules from a gas, liquid, or dissolved phase to a surface, forming an adsorbed layer. The species that accumulates on the surface is called the adsorbate, while the surface material is the adsorbent. In Portuguese, adsorvendo is the present participle used to describe the ongoing process of adsorption.

Adsorption is a surface phenomenon distinct from absorption, which involves uptake into the bulk. There are two main mechanisms: physisorption, governed by weak van der Waals forces, usually reversible and highly dependent on temperature and pressure; and chemisorption, involving the formation of chemical bonds, with higher enthalpies and often more selective and less reversible.

Adsorption behavior is commonly described by isotherms that relate the amount adsorbed to the concentration or pressure at constant temperature. The Langmuir isotherm models monolayer adsorption on homogeneous sites, while the Freundlich isotherm describes heterogeneous surfaces. Kinetics can follow pseudo-first-order or pseudo-second-order models, reflecting how quickly adsorption proceeds.

Applications are broad: water treatment and air purification, where contaminants are removed by contacting fluids with adsorbents such as activated carbon, zeolites, or silica gels; catalysis and energy storage; chromatography and gas separation, including CO2 capture. Regeneration of spent adsorbents by heat, solvent washing, or pressure changes is common, though some adsorbents degrade on reuse.

Adsorption is a key mechanism in environmental engineering, chemical processing, and materials science, valued for its simplicity and selectivity, but limited by capacity, selectivity, and the need for regeneration.