improving the separation of thorium and uranium ions from wastewater by impregnating amberlite xad-4 resin

Thorium and uranium are one of the most important heavy metals because of the chemical toxicity and radioactivity. excessive amounts of thorium and uranium have entered into environment through the activities of nuclear industry. the toxic nature of thorium and uranium ions, even at trace levels, has been a public health problem for many years. for this reason, removal of thorium and uranium ions from wastewater is of great importance [1]. the solid phase extraction technique is now routinely used in various research and application areas due to its characteristics and advantages over the classical solvent extraction or other pre-concentration techniques. chelating resin sorption method is one of the most effective multielement pre-concentration methods. in this study, amberlite xad-4 resin for improve the separation and removal thorium and uranium ions from nuclear waste was investigated and in view of this point that the adsorptive properties of adsorbent can be improved [2, 3], impregnation of the xad-4 surface by complexing agent bis(2-hydroxybenzaldehyde)-1,2-ethylendiimine was done. the results show the adsorptive properties of adsorbent can be improved by impregnation of the surface with complexing agent. the procedure was based on the adsorption of thorium and uranium ions on amberlite xad-4 resin loaded with a schiff base prior to their determination by inductive coupled plasma spectrometry. a comparison of the adsorption efficiency of the studied resin loaded with a schiff base with those unloaded ones shows a shift for uptake of the metal ions vs. ph curves towards lower ph the values by applying the loaded resin with schiff base. also, δph0.5 th/u increases from 0.2 to 1.4 and a selective separation occurs for the thorium ion. the effect of parameters influencing such as aqueous phase ph, contact time and adsorbent dosage was investigated. under optimal conditions (ph=5, adsorbent amount 0.1 g, contact time 45 min.) for thorium ions and (ph=6, adsorbent amount 0.1 g, contact time 60 min.) for uranium ions with initial concentration 20 mg/l were quantitatively removed from 20 ml of the sample solution (99.28% for thorium and 97.35% for uranium). the kinetic data corresponds well to the pseudo-second-order equation. this model predicts chemisorption for the adsorption. the adsorption data for studied ion were well fitted by the frundlich isotherm.