Facile preparation of polyethyleneimine modified activated sludge-based adsorbent for hexavalent chromium removal from aqueous solution

Polyethyleneimine modified activated sludge (AS-PEI) was prepared and used for the removal of Cr(VI) in wastewater. Characterized results exhibited that PEI was successfully anchored on the surface of activated sludge. At 25 ºC and pH = 5.0, the maximum adsorption amount of Cr(VI) on AS-PEI was 86.96 mg/g. The adsorption amount of AS-PEI for Cr(VI) decreased as the pH values increased. The existence of Cl-, SO42- and PO43- decreased the Cr(VI) adsorption, and HA enhances the Cr(VI) adsorption. The electrostatic interaction combined reduction was the main mechanism of Cr(VI) adsorption. Cr(VI) loaded adsorbent can be regenerated in alkaline solution and AS-PEI can be reused.