# Application of Modern Research Methods for the Physicochemical Characterization of Ion Exchangers
## Materials and Methods
### Instruments  
Optical profilometry enables precise, spatial microgeometry imaging of the surface of selected ion exchangers Dowex M 4195, Amberlite IRA 743 and Purolite Arsen X\({}^{\rm mp}\). The basis of the profilometer operation is the phenomenon of light interference and analysis of the interference fringes pattern. The light beam, whose source is the LED, is divided by passing through the interference lens. One part of the beam is reflected from the sample surface, the other from the reference mirror. Returning, both beams interfere with each other, creating an interference pattern on the detector of the surface being tested. The location of the obtained profile in the axis \(Z\) gives the possibility to generate a 3D map of the studied area (the resolution in the \(Z\) axis is independent of the scanning range and being equal to 3 nm). The profilometer ContourGT-K1 (Vecco, Bruker, Leiderdorp, The Netherland) works in two ways: VSI (Vertical Scanning Interferometry) with the maximum height of scanning 10 mm) and PSI (Phase Shifting Interferometer) for super smooth surfaces with less than 30 nm roughness. Before performing profilometric tests, the ion exchanger beads were cut with an ultramicrotome. The step in the ultramicrotons was set to 5 nm. The tests were performed using an accredited method for three ion exchanger beads before and after the sorption process. To this aim, the software Vision 64, ver. 5.41 update 4 was applied. According to the test procedure, five measurements are made for each object and the result is given as the average of five measurements. In the accredited method, the measurement uncertainty was estimated: The roughness measurement uncertainty, R\({}_{\rm a}\), was estimated, taking into account repeatability, recovery and decalibration of the apparatus and the uncertainty of the standard. The uncertainty was estimated for the two extreme \begin{table}
\begin{tabular}{c c c c} \hline
**Properties** & **Dowex M 4195** & **Amberlite IRA 743** & **Purolite Arsen X\({}^{\rm mp}\)** \\ \hline Appearance & dark green & white & reddish-brown \\ \hline Matrix & ST-DVB & ST-DVB & ST-DVB \\ \hline Structure & macroporous & macroporous & macroporous \\ \hline Functional groups & bis-picolylamine, bis(2-pyridyl-methyl) & N-methyl-glucamine (free base form) & sulfonic acid groups/hydrated iron oxide nanoparticles \\ \hline Size (mm) & 0.300–0.8500 & 0.500–0.700 & 0.300–1.200 \\ \hline pH range & 0–14 & 0–14 & 4–9 \\ \hline Max temp. (\({}^{\circ}\)C) & 80 & 75 & 80 \\ \hline S\({}_{\rm BET}\) (m\({}^{2}\)/g) & 3.2 & 14.5 & 7.1 \\ \hline pH\({}_{\rm ZPC}\) & 2.4 & 8.00 & 8.31 \\ \hline Total capacity (eq/L) & 1.4 (6 g Cu(II)/L) & 0.7 & 0.8 \\ \hline \end{tabular}
\end{table} 
Table 1: Physicochemical properties of Dowex M 4195, Amberlite IRA 743 and Purolite Arsen X\({}^{\rm mp}\). points of the R\({}_{\rm a}\) measurement range (upper and lower limits) with the assumption of a trapezoidal distribution. The expanded uncertainty of the roughness measurement was given with and without taking into account the standard uncertainty. In order to investigate the chemical structure of the ion exchangers, the studies were carried out by means of the ultra-high vacuum multi-chamber analytical system (Prevac, Rogowo, Poland). After mounting on a molybdenum carrier (Figure 6), the samples were degassed at room temperature to a constant high vacuum of \(\sim\)5 \(\times\) 10\({}^{-8}\) mbar, in the loading shuice of the UHV system. AlK\(\alpha\) monochromatic radiation was used as a source of photoelectrons. Photoelectrons were stimulated by X-ray of a characteristic line AlK\(\alpha\) of 1486.7 eV energy, generated by a VG Scienta SAX 100 lamp with an aluminium anode with a VG Scienta XM 780 monochromator. The pressure in the chamber during the measurements was 2 \(\times\) 10\({}^{-8}\) mbar. The X-ray tube operating parameters were as follows U 12 kV, Ie 30 mA.