Adsorption behavior and mechanism of emerging perfluoro-2-propoxypropanoic acid (genx) on activated carbons and resins
Answers
As a typical alternative to perfluorooctanoic acid (PFOA), perfluoro-2-propoxypropanoic acid (GenX) has been detected worldwide in aquatic environment and attracted great concerns recently, but their adsorptive removal from water is not clear. In this study, the adsorption behavior and mechanism of GenX on granular activated carbon (GAC), powdered activated carbon (PAC), anion-exchange resins (IRA400 and IRA67) were compared. The particle size of activated carbon (AC) affected the initial adsorption rate but exhibited little influence on the adsorption capacity for GenX. The initial adsorption kinetics of GenX on the three granular adsorbents (GAC, IRA67 and IRA400) followed the intraparticle diffusion-controlled adsorption.
Theory:
Adhesion of atoms, ions, bimolecules or molecules of gas, liquid or dissolved solids to a surface is called adsorption. This process creates a film of the adsorbate –the molecules or atoms being accumulated, on the surface of the adsorbent.
Examples:
Activated charcoal adsorbs gases like CO2 , SO2, Cl2 etc.
Pt or Ni metal kept in contact with a gas adsorbs the gas - Hydrogenation of oils.
Animal charcoal, when added to acetic acid solution and shaken vigorously, adsorbs acetic acid.
Molasses is decolourised by activated charcoal.