Molecularly imprinted smart cryogels for selective nickel recognition in aqueous solutions

Smart polymers with fast response to slight changes show high practicability in separation and removal applications, such as water and wastewater treatment. Molecular imprinted polymers (MIPs) are designed to possess specific binding sites enabling the recognition of the target analytes. In this article, the newly synthesized smart adsorbents were used for the selective removal of nickel [Ni(II)] ions from aqueous solutions, which have dual (pH and temperature) memory for the recognition of Ni(II) ions due to the self-assembled recognition sites in MIP structure. The Ni(II)-MIP smart cryogels were prepared by cryopolymerization ofN-isopropylacrylamide (NIPAm) andN-methacryloyl-l-histidine (MAH) monomers to incorporate their smart features for removal of Ni(II) ions in a selective and temperature-modulated way. The maximum binding capacity of Ni(II) ions onto MIP smart cryogel was determined at pH 6 as 414 mu g g(-1)at 20 degrees C and only 104.5 mu g g(-1)at 40 degrees C, respectively. The adsorption reached an equilibrium within 30 min, while 85% of the bound amount of Ni(II) ions was achieved in only 15 min. This unique MIP cryogel as a smart and selective adsorbent was able to remove Ni(II) ions immediately by a significant temperature and pH change as an alternative application for water and wastewater treatment.

Automated summary

The newly synthesized smart adsorbents used in this study are capable of selectively removing nickel [Ni(II)] ions from aqueous solutions with dual (pH and temperature) memory due to self-assembled recognition sites in the MIP structure. These smart cryogels demonstrate a maximum binding capacity for Ni(II) ions and achieve equilibrium adsorption within a short time frame, making them efficient and practical for water and wastewater treatment applications.