Synthesis of Composite Material and Environmental Application

Abstract

Iron oxy hydroxide nanoparticles were synthesized from natural acid leached solution of natural hematite ore and FeCl3 solution. Microernulsion technique was used to synthesize the nanoparticles using a surface active agent. Solution of chloride salts of iron was prepared from hematite ore using acid leaching technique and that precursor was used to prepare the iron oxy hydroxide nanoparticles. The various process parameters were optimized during synthesis of nanoparticles like pH, dilution of the precursor, surfactant-co-surfactant ratio and critical micelle concentration of surface active agent to obtain smaller size nanoparticles. The synthesized nanoparticles was characterized using dynamic light scattering (DLS) analyzer, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), BET surface area analyzer. Nanoparticles of average diameter of 6-20 nm were revealed through TEM analyses. A chitosan as polymer was mixed with iron oxy hydroxide nanopartcles under suitable experimental conditions to obtain a composite fluoride adsorbent. A comparative fluoride adsorption study was made between the nanoparticles and the composite. The specific surface area and total pore volume of the nanoparticles sample obtained under optimized process condition were 3 12 m2/g and 0.2 mUg, respectively. Batch adsorption isotherm study reveals that with an initial fluoride concentration of 50 mglL and adsorbent dosing 0.75 gIL, the adsorption of fluoride was observed 58.8 mglg within the 15 nlin of agitation time for the nanoparticles and for composite adsorbent was 78.8 mg/g under other experimental condition kept constant. Different adsorption isotherms were fitted with experimental data and it was found that in this study Freundlich isotherm model fitted best. Similarly, for adsorption kinetic model fit, the pseudo second order kinetic model was explained experimental kinetic data more satisfactorily.