Research And Application Progress Of Modified Attapulgite In Sorption Heavy Metal Ions

Attapulgite was characterized and organo-modified to prepare one novelmaterials.Attapulgite was modified with silicon hydride couping agent.An extensive study was performed on the mineral characteristics and modificationmechanism of attapulgite in term of basal spacing(XRD), scanning electronmicroscope (SEM), chemical composition(FT-IR spectroscopy).Palygorskite is mainly composed of attapulgite, often accompanied by opal naturalattapulgite clay, quartz and carbonate, etc., at the same time because of van der Waalsforce and hydrogen bonding interaction, attapulgite clay crystal rods generally exist inaggregate form, limits the performance of attapulgite clay and the range of application.Before use, therefore, often need to adopt appropriate methods to remove impuritiesfrom the great crystal aggregates reconciliation.Acid treatment can be partial depolymerization of attapulgite clay crystal rodbundle, change the specific surface area of attapulgite clay, get rid of the impurityminerals such as carbonate. And hydrogen ions can replacement attapulgite claycontaining iron, aluminum and magnesium ions and metal ions, such as ion increaseattapulgite cationic exchangeability, decoloring force and improve the attapulgite clayadsorption.There were lots of water and hydroxy group in the attapulige surface, has a strongaffinity to organic matter, and hydrolysis of silane coupling agent can generatehydroxyl silicon, the silicon hydroxyl with attapulgite can be produced a lot of surfacecondensation, or silicon hydroxyl silane coupling agent self condensation, covered inattapulgite surface, modification of the surface morphology and properties, to form anew network structure, and enrich the channel of attapulgite, the synthesis of a newtype of functional material, which gives attapulgite new performance.Attapulgite clay hydrochloric acid after treatment with silane coupling agentmodification. Determine the technological conditions for:75ml concentration in4mol/L HCl solution, to join the acidified attapulgite clay,7.500g products in120℃drying after washing neutral. With1:1proportion to join the silane coupling agent, the temperature controlled at70℃, the mechanical agitation for5h, the suction filterwashing drying product.The sorption behavior of Co(II) and Pb(II) from aqueous solution to attapulgite wasinvestigated as a function of contact time, pH, fulvic acid (FA), solid content, ionicstrength, foreign ions and temperature. The results indicated that the sorption of metalions on attapulgite was quickly and several hours were enough to achieve the sorptionequilibration. The sorption was strongly dependent on pH and ionic strength. Thesorption was mainly dominated by surface complexation at high pH values and by ionexchange at low pH values. The sorption isotherms were simulated by the Langmuir,Freundlich, and Dubinin-Radushkevich (D-R) models respectively. The sorptionisotherms of Pb(II) was simulated by Langmuir model very well.The results suggested that the modified attapulgite was suitable as a sorbentmaterial for the recovery and sorption of heavy metal ions from aqueous solution.