“…The object of this study was a spent adsorbent based on saponite (Ukraine) with an applied layer of ferrihydrite in a ratio of 1:1 (Sap-Fh), synthesized according to [10]. To simulate a contaminated water system, a model solution with a Cr (VI) concentration of 50 mg/dm 3 , a pH of 5.2, and an ionic strength of 0.01 based on NaCl was employed.…”