Study On Surface Characteristic Of Palygorskite And Interface Reaction Of Heavy Metal Ions To Palygorskite

Palygorskite is a chain-layer magnesium-aluminum silicate. Since it was discovered in the 19th century, few attention has been paid on the adsorption mechanism of heavy metal ions to the long-term reaction of heavy metal ions and palygorskite.The paper supplemented the former study on adsorption properties of palygorskite. The long-term reaction mechanism of heavy metal ions to palygorskite and the stability of result of the reaction are the emphasis of my study.The interaction of heavy metal ions to palygorskite includes layer cation exchange, surface complexation. ion exchange of metal ions with octahedral cations of palygorskite and induced hydrolysis and precipitation of metal ions by palygorskite. Generally, the main mechanisms of heavy metal ions removal by palygorskite are induced hydrolysis and precipitation of heavy metal ions by palygorskite surface hydration, and electrostatic interaction between colloidal particles.The long-term reaction of heavy metal ions to palygorskite could be well fitted with parabola, two-constant, first-order diffusion and Elovich equations. During the reaction, the octahedral dissolution of palygorskite induced heavy metal ions coprecipitation forming mixed double hydroxid precipitation on the surface of palygorskite. which is more steady than the heavy metal ions mononuclear precipitation. Induced hydrolysis and precipitation of metal ions by mineral-water interaction is an important interfacial interaction.