Sepıolıte Embedded Nanocomposıte Cartrıdges For Heavy Metal Removal From Water

Abstract

A natural clay mineral, sepiolite (Mg4Si6O15(OH)2·6H2O), with a unit cell formula has fibrous structure, which has inside channels and sepiolite’s high surface area lets inorganic and organic ions penetration into the clay structure. These properties make to be candidate for removing cationic molecules, heavy metals, organic compounds and even pesticides in industrial field. Polymer-based cryogels are known to be frequently used in purification and removal processes. In recent years, the use of sepiolite group of cryogels with composite materials and cryogels in water treatment systems has attracted attention. In this thesis, heavy metal (As, Pb, Cr, Cd etc.) removals from water environment with sepiolite embedded cryogels was investigated. The surface morphology and porosity of sepiolite embedded nanocomposite was characterized by Fourier Transform Infrared (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), computed microtomography (mCT), puffing studies, flow and surface area evaluations. Binding tests will be performed by investigation of impact of initial concentration of a certified material. The impact of nanocrystallized sepiolite mineral on the amount of adsorbed metal from certified heavy metal solutions was determined using ICP-MS. Cryogels without sepiolite added were prepared as controls. This study demonstrates that the presence of ii sepiolite increases the heavy metal adsorption. The sepiolite embedded nanocomposites were applied to a continuous treatment system for heavy metal removal from water solutions. Accordingly, %90 of heavy metals (Cr, Fe, Co, Zn and Cd) were adsorbed onto sepiolite embedded nanocomposite cryogels with maximum adsorption capacity. The adsorption time of sepiolite embedded nanocomposite cryogels was obtained as 30 minutes. Furthermore, the binding isotherms were evaluated by Langmuir and Freundlich models for heavy metals as Mn, Ni, As, Se, Cd, Sb and Co. It was calculated that Langmuir isotherm was well fitted with adsorption via monolayer. In addition, the binding mechanism of sepiolite embedded nanocomposite cryogels was defined by pseudo second order kinetics. It was concluded that adsorption mechanism of heavy metals onto sepiolite embedded nanocomposite cryogels can be explained by chemically controlled.