Purification of Nitrate Contaminated Aqueous Solution Using Modified and Unmodified Palmkernel Shell

Abstract

The adsorption capacity of Palmkernel shell (PKS) which was used as an adsorbent in this study were boosted by acid thermoactivation. The nitrate sorption potential, point zero charge (PZC) and surface area of the PKS were enhanced by the acid thermoactivation process. The process of sorption of nitrate from solution was analyzed using five different isotherm models [Langmuir, Freundlich, Temkin, Harkins-Jura, and Halsey isotherm equations]. The value of the Langmuir monolayer sorption capacity qm [mg/g] increased from 60.12 to 85.73, PZC values increased from 5.50 to 8.40, and the surface area [m2/g] value increased from 29 m2/g to 98 m2/g after the activation process. The effect of pH on the sorption of the nitrate on both sorbents was also considered and it was discovered that the adsorption of nitrate decreases with increase in nitrate solution pH. The effects of the sorbents dose on the sorption process was also studied and the results showed that the amount of nitrate sorbed by both sorbent decreases with increase in sorbent dose.