Kinetic and equilibrium studies of adsorptive removal of sodium-ion onto wheat straw and rice husk wastes

The presence of solutes in water and soil resources is one of the main environmental problems of many societies. The purpose of this study was to evaluate and compare the removal of sodium onto the wheat straw and rice husk wastes nanostructured sorbents. This study was conducted in a batch experiment scale with changes in effective factors such as pH (4.3, 5, 6, 7, and 8), contact time (10, 30, 60, 90, 120, and 180 minutes), sorbent dosage (0.3, 0.5, 0.7, 1, 1.3, and 1.6 g), and the initial concentration (5, 10, 30, 60, 90, and 120 mg/L) of sodium metal solution were investigated. Sodium adsorption kinetics on the prepared sorbent was examined based on isotherms of absorption equations. The results showed that the adsorption efficiency of the sorbent studied increases the increasing in pH from 3 to 5, but that the metal ion deposited at a pH greater than 5. Increasing the contact time increases the adsorptive efficiency. In addition, efficiency first increased and then, decreased by increasing the amount of nanometer sorbent. Increasing the initial concentration of sodium from 5 to 120 mg/L for the wheat straw and rice husk wastes sorbents cause decreasing the adsorption efficiency from 85.49 to 68.07% and 89.43 to 68.2% due to lack of sufficient adsorbent higher sodium ion content. Consequently, the adsorption capacity increased from 0.34 to 9.43 mg and 0.36 to 9.43 mg.