Silk fibroin/polyethylenimine functional hydrogel for metal ion adsorption and upcycling utilization

The indiscriminate disposal of heavy metal ions poses serious threat to the environment and public health. Herein, we report a sustainable and low-cost silk fibroin (SF)/polyethyleneimine (PEI) composite hydrogel for the remediation of heavy metal ions in the aqueous solutions. The SF/PEI hydrogel demonstrated excellent adsorption capacities for the Cu(II), Pb(II), Cd(II), Zn(II), Ni(II), and Ag(I) ions, which are 163.9, 185.2, 169.5, 125.0, 140.8, and 200.0 mg g −1 , respectively. Via a stepwise adsorption, reduction and utilization procedure, the as-prepared hydrogel shows versatile functionalities depending on the pristine adsorbed metal ion(s), for example, catalytical activity and antibacterial property. Based on the functional SF/PEI hydrogel, engineering the cascaded treatment procedure will provide an effective and practical paradigm for the treatment and recycling of heavy metal ions in the wastewater.