Removal of hexavalent chromium from simulated wastewater by Polyethylene glycol modified D201 resin supported nanoscale zero-valent iron

Abstract In view of the increasingly prominent heavy metal pollution problem in water, polyethylene glycol modified D201 resin supported nanoscale zero-valent iron (PEG-nZVI/D201) was fabricated to remove Cr(VI) in wastewater. PEG-nZVI/D201 can overcome the agglomeration and oxidation drawbacks of nZVI effectively, and improve the removal efficiency of Cr(VI). Its Cr(VI) removal rate was 33.6% higher than that of bare nZVI when the dosage of PEG-nZVI/D201 was 1.0 g·L− 1, the Cr(VI) concentration was 50 mg·L− 1 and initial pH was 5.0. The Langmuir model better describes the adsorption of Cr(VI) on PEG-nZVI/D201. Thermodynamic parameters show that adsorption is spontaneous and endothermic. The mechanism of Cr(VI) removal by PEG-nZVI/D201 is as follows: firstly, protonated PEG-nZVI/D201 adsorbs Cr(VI) by electrostatic attraction, then nZVI reduces most of Cr(VI) to Cr(III) through its strong reducibility, and finally Cr(III) can form CrXFe1−X(OH)3 co-precipitation with Fe(III) produced by oxidation of nZVI.