An Integrated Approach for the Recovery of Sn from Used Water Adsorbents

This research examined a scenario for the recovery of high-capacity Cr(VI) adsorbent, consisting Sn6O4(OH)4, after reaching its operational lifetime. To accomplish this target, sequence processes involving spent adsorbent’s decomposition, separation Sn/Cr ions, and Sn6O4(OH)4 reconstruction was investigated. Characterization saturated adsorbent indicated extended oxidation to SnO2 during use according occurring Cr(III) reduction mechanism, which is responsible loading 19 mg Cr/g. decompose optimized process involved dissolution by HCl using solid concentration 10 g/L, acid mass proportion 1:20, an increase temperature at 75 °C. Such conditions brought rate more than 95% 92.5%, respectively, total Sn Cr in adsorbent. Then, succeeded addition hydrazine, acts as reducing agent transformation Sn(IV) Sn(II); precipitation pH 3, second step increasing 7. The recovered stabilized higher percentage Sn(II) initial material, explains improvement removal efficiency 50% adsorption capacity.