APPLICATION OF CHELATE FORMING SORBENT CONTAINING FRAGMENTS OF ACETAMIDE OF BENZOIC ACID FOR SORPTION EXTRACTION OF THORIUM (IV) FROM CLAY
Thorium, like all other radioactive elements, is a highly undesirable impurity in all environmental objects. Due to radioactive toxicity, establishing its presence and extracting it has always been an urgent task. In this work, we propose a new, selective, and simple procedure for the sorption-spectrophotometric determination of trace amounts of thorium (IV). A polymer chelating sorbent containing fragments of acetamide of benzoic acid was investigated. The effect of acidity among the sorption of thorium (IV) by a polymer sorbent in the range of pH 1-10 was investigated. The results of the analysis showed that quantitative absorption is achieved at pH 4. The dependence of sorption on ionic strength was investigated. The obtained results of the analysis showed that an increase in the ionic strength to 0.2 does not affect the sorption process, the next increase is the reason for a decrease in sorption. This is explained by the fact that with an increase in the ionic environment of the functional groups, the possibility of thorium(IV) complex formation decreases. The effect of the metal concentration on the sorption process was studied. An isotherm of thorium sorption with this sorbent was constructed and the optimal concentration conditions were determined: pH = 4, C<sub>Me</sub>= 0.006 mol-l<sup>-1</sup>, V= 25 ml, m<sub>sorb</sub> = 0.03 g, SC = 1206 mg-g<sup>-1</sup>. The dependence of the sorption process on time was also studied. The results of the analysis showed that thorium (IV) is completely absorbed after 2.0 hours, under static conditions. After determining the optimal conditions for the sorption of thorium (IV) by the synthesized sorbent, the process of desorption of the absorbed metal from the sorbent was also studied. The influence of various mineral acids (HClO<sub>4</sub>, H<sub>2</sub>SO<sub>4</sub>, HNO<sub>3</sub>, HCl) on the desorption of absorbed thorium (IV) from the sorbent was also determined. The results of the study showed that the maximum desorption of thorium (IV) occurs in perchloric acid. Having determined the optimal acid for the desorption of thorium (IV) from the sorbent, the influence of the eluent concentration on the desorption process was studied. The results of the analysis showed that the maximum desorption of sorbed thorium (IV) occurs in perchloric acid with a solution concentration of 2 M. The developed method of application for the determination of trace amounts of thorium (IV) in clay with preliminary concentration. The correctness of the method was checked by the method of additions.