Studies on the Mechanism of Cu(II) Ion Sorption on Purolite S 940 and Purolite S 950

Weronika Sofińska-Chmiel; Dorota Kołodyńska; Agnieszka Adamczuk; Aleksander Świetlicki; Marta Goliszek; Radosław Smagieł

doi:10.3390/ma14112915

Studies on the Mechanism of Cu(II) Ion Sorption on Purolite S 940 and Purolite S 950

Materials (Basel). 2021 May 28;14(11):2915. doi: 10.3390/ma14112915.

Authors

Weronika Sofińska-Chmiel¹, Dorota Kołodyńska², Agnieszka Adamczuk³, Aleksander Świetlicki⁴, Marta Goliszek¹, Radosław Smagieł⁵

Affiliations

¹ Analytical Laboratory, Institute of Chemical Sciences, Faculty of Chemistry, Maria Curie Skłodowska University, Maria Curie Skłodowska Sq. 2, 20-031 Lublin, Poland.
² Department of Inorganic Chemistry, Institute of Chemical Sciences, Faculty of Chemistry, Maria Curie Skłodowska University, Maria Curie Skłodowska Sq. 2, 20-031 Lublin, Poland.
³ Institute of Agrophysics PAS, Doświadczalna 4 Str., 20-290 Lublin, Poland.
⁴ Department of Materials Engineering, Mechanical Engineering Faculty, Lublin University of Technology, Nadbystrzycka 36 Str., 20-618 Lublin, Poland.
⁵ Biolive Innovation, B. Dobrzańskiego 3 Str., 20-262 Lublin, Poland.

Abstract

The aim of the presented research was to investigate the mechanism of sorption of Cu(II) ions on the commercially available Purolite S 940 and Purolite S 950 chelating ion exchangers with the aminophosphonic functional groups. In order to understand better the sorption mechanism, the beads were cut with an ultramicrotome before and after the Cu(II) ion sorption process. The cut beads were examined by scanning electron microscopy (SEM) with an EDX detector. The performed linear profiles of the elemental composition allowed us to examine the depth with which the sorbed metal penetrates into. For further investigations concerning the mechanism of the sorption process, the Fourier transform infrared spectroscopy (FTIR) analysis using the attenuated total reflectance (ATR) technique and the X-ray photoelectron spectroscopy (XPS) methods have been used. The comparison of FTIR and XPS spectra before and after the sorption of Cu(II) ions showed that free electron pairs from nitrogen and oxygen in the aminophosphonic functional groups participate in the process of copper ion sorption. In addition, the microscopic studies suggested that the process of ion exchange between Na(I) ions and sorbed Cu(II) ions takes place on the Purolite S 940 and Purolite S 950. This study concerning the in-depth understanding the of Cu(II) sorption mechanism, using modern analytical tools and research methods could be very useful for its further modifications leading to the improvement of the process efficiency.

Keywords: Purolite S 940; Purolite S 950; copper; heavy metals; ion exchangers; sorption mechanism.