Extraction of Ni (II) by Modified Magnetite Nanocomposite Adsorbent

The present study investigates the extraction of Ni (II) from water by applying surface modified silica-coated magnetite nanocomposite as an adsorbent. Magnetite nanoparticles are synthesized by co precipitation method, using ferric and ferrous salts in basic medium. Silica coating is done by Stober method of sol-gel hydrolysis, using precursor TEOS. Surface of silica-coated magnetite nanoparticles are modified with hexa-dentate ligand (EDTA) via acid catalyzed sol-gel hydrolysis. Size of the magnetite nanocomposite is determined by XRD and SEM and is found to be 15-18 nm in range. Silica coating and functionalisation with EDTA are confirmed by EDX and FT-IR characterization. Magnetic property is studied by VSM and the nanocomposites are found to be super paramagnetic at room temperature. Batch experiment is carried out to study the adsorption kinetics and mechanism of nickel adsorption by magnetite nanocomposite. The adsorption process is found to be pH dependent and equilibrium is attained within 15 minutes. Adsorption data is well fitted with Langmuir adsorption model. Reaction parameters such as pH, amount of adsorbent, time taken to complete adsorption are studied and optimized. Regeneration study indicates that magnetite nano composite follows successive adsorption and desorption cycle and retain original metal removal capacity till five cycles are completed.