SYNERGISTIC EFFECTS BETWEEN NITROGEN FUNCTIONALITIES AND METALS CONTENT ON THE REMOVAL OF PHOSPHATE IONS

摘要

The release of phosphate ions in the runoff is today a major threat to the environment and humans. Therefore, it is vital to develop effective technologies to remove phosphate ions from aqueous solutions before they are discharged into runoff and natural water bodies. This study aims to evaluate and proposed a mechanism of phosphate adsorption by using nitrogen and metals-functionalized chars. In order to isolate the contribution of individual components of lignocellulosic biomass, simple cellulose was used for the char production. Five samples of nitrogen-doped chars were produced via annealing cellulose under ammonia gas at different temperatures (500, 600, 700, 800, 850 and 900 °C). Some of the analytical techniques used for the chars characterization were: Elemental and proximate analysis, gas physisorption analysis, Scanning Electron Microscopy and X-ray photoelectron spectroscopy analysis. These samples were subsequently used for phosphate adsorption. Characterization of the resulting chars shows an increase of the nitrogen content in the samples, where the greater percentage of it appears at a temperature of 800 °C (12.5 wt%) and the maximum surface area was for char produced at 900 °C (1314 m~2/g).