MODIFICATION OF THE ORGANO-POLYMERIC ANIONITES SURFACE WITH XYLENOL ORANGE BY SORPTION

Анотація

In this paper, the peculiarities of xylenol orange sorption removal with the help of organopolymeric anion exchangers AB-17-8 and Granion AWA-G1 in the static mode are studied. The state of the matrix and the surface of the organopolymeric anion exchanger granion AWA-G1 was characterized by the IR and Raman spectroscopy. It was established that at pH 5 and 9 the maximum sorption removal (90-95%) of xylenol orange by organopolymeric anion exchanger Granion AWA-G1 lasts for 60 minutes. On the basis of the obtained sorption isotherms and the calculated thermodynamic characteristics, it was concluded that the formation of the adsorption layer occurs spontaneously by a mixed mechanism. The initial process of adsorption layer formation due to chemisorption mechanism. Below, at high concentration of xylenol orange the sorption mechanism changes to the physical nature. It was shown that with changes in temperature and pH, the type of isotherms changes from L3 to H4, which indicates a high affinity of the adsorbate to the adsorbent surface. The obtained sorption isotherms are satisfactorily described by the Langmuir adsorption model. It was shown that the increase in temperature is accompanied by an increase in the amount of sorbed xylenol orange, which is due to the acceleration of the process of reorientation of sorbate molecules to the vertical. In the study of xylenol orange desorption from the Granion AWA-G1 anionite surface, it was found that distilled water and 1M solutions of sulphuric acid slightly desorb xylenol orange (Sdes ≤ 25%), in contrast, the desorption of xylenol orange with 1 M sodium hydroxide solutions reaches Sdes ~ 65%. Thus, the organopolymeric anion exchanger granion AWA-G1 modified with xylenol orange is resistant to water and acid desorption and can subsequently be used as a solid-phase reagent.