ADSORPTION OF DISSOLVED IONS IN MINE WASTEWATER WITH LATERITE AND IRON OXIDE NANOPARTICLES. A RESEARCH PROJECT TOPIC ON SCIENCE AND ENGINEERING
ABSTRACT
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.
CHAPTER ONE
BACKGROUND
1.1Â Â Â Â Â Â Introduction
High quality water is a critical resource with invaluable socio-economic and environmental value and significance worldwide. The growing concern with water quality and increasing stringent environmental regulation has brought focus on water recycling, water treatment and minimization of water used in the mining and process industries. Conventional treatments to meet allowable concentrations of contaminants in water before discharge are being challenged due to economics and cost factors in technology and selection. Effective sustainable development must, therefore, ensure uncontaminated streams, rivers, lakes and oceans (Nkwonta and Ochieng 2013). Under current practice, water draining from process industries and base metal mines frequently contain organic, inorganic and heavy metals at high levels. When the contaminants in the effluents become higher than the set standards, disposal becomes a challenge.
