Thiourea-Immobilized Polymer Beads for Sorption of Cr(VI) Ions in Acidic Aqueous Media

Polymer sorbents used for the removal of hexavalent chromium (Cr(VI)) ions from highly acidic aqueous media (pH≤1) are needed. In this study, micronsized polystyrene beads containing immobilized thiourea (mTA-PS) were prepared through suspension polymerization and two successive chemical modifications. The sorbent was stable even at pH of 0 under room temperature. The effects of pH, contact time, and initial concentration on sorption of Cr(VI) anions were studied. The isotherm data was fitted to the Freundlich model accordingly. The Langmuir model predicted the sorbent to have a maximum sorption capacity of 137 mg g−1 at pH 1. The sorbent exhibited a significant selective sorption of Cr(VI) ions over trivalent chromium (Cr(III)) ions. These results show that such polymer sorbent can be utilized to remove Cr(VI) ions from a highly acidic aqueous media.