Adsorption of Dissolved Ions in Mine Wastewater with Laterite and Iron Oxide Nanoparticles
This work studies the adsorption capacity of laterite and iron oxide nanoparticles for dissolved ions in solution and therefore its ability to reduce conductivity of mine waste effluent. Three laterite samples were prepared and used as adsorbents. The first laterite adsorbent was used without any treatment, the second was heat treated and the third was mixed with 15 % iron oxide nanoparticles of particle size 100 nm. Laterite and nanoparticle characterization, pH and adsorption tests were conducted to ascertain the composition of laterite and as-prepared iron oxide nanoparticles, the adsorption capacity of the adsorbents and the optimum conditions for adsorption. The X-ray diffraction. (XRD) results of both pure and heat-treated laterite showed the main minerals present to be: Quartz (SiO2), Alumina (Al3O4), Berlinite (AlPO4) and Hematite (Fe2O3). The XRD results for synthesized iron oxide nanoparticles showed the mineral Magnetite (Fe3O4). The adsorption results of heat-treated laterite showed the highest adsorption capacity for total dissolved ions at a pH range of 6.5 - 6.8. Laterite and nanoparticles composite had the highest adsorption capacities for Ca and Mg ions.