Effective and selective scavenging of Cr(VI) by novel triethylenetetramine-modified sodium lignosulfonate ion imprinted polymer from wastewater: Performance, mechanism, and application

A novel ion-imprinted polymer (SIIP) was synthesized by modifying sodium lignosulfonate (SL) with triethylenetetramine (TETA) to selectively adsorb Cr(VI) from wastewater. SIIP exhibited a high adsorption capacity for Cr(VI) of 464.73 mg/g, which is 1.1 times higher than that of TETA-modified SL (TS). SIIP reached adsorption equilibrium for Cr(VI) within just 30 min. In the single Cr(VI) solution system, the selective adsorption amount of SIIP for Cr(VI) was 75.81 mg/g, while in the mixed Cr(VI)/Cu(Ⅱ) solution system, it was 29.55 mg/g. These values were greater compared to those of the unmodified TS, demonstrating the enhanced adsorption performance of SIIP. In view of the similarity between SO₄^2– and HCrO₄^– in terms of molecular size and hydration energy, during the adsorption of Cr(VI) by SIIP, the SO₄^2– had a remarkably obvious effect on the co-existing ion adsorption. The mechanism analysis revealed that the adsorption of Cr(VI) by SIIP involved surface complexation reactions, reduction processes, and electrostatic attraction effects. These findings suggest that SIIP holds substantial potential in the realm of Cr(VI) containing wastewater treatment.