Preparation of nanocellulose grafted molecularly imprinted polymer for selective adsorption Pb(II) and Hg(II)

Heavy metal pollution has become a major problem in environmental pollution. Ion imprinted polymers with specific identification and wide practicality have gradually become an important tool for wastewater treatment. In this work, ion-imprinted polymer-grafted modified nanocellulose was designed as an adsorbent for the serious hazard of Pb(II) and Hg(II) in wastewater. This work used medical cotton wool as raw material to prepare a nanocellulose suspension by acid-catalyzed hydrolysis. The high reactivity of carbonyl diimidazole (CDI) was utilized to react with acrylic acid (AA) to generate reactive intermediates, which then reacted with nanocellulose to form activated nanocellulose (AA-CDI-NC). Crown ether was used as functional monomers to synthesize Pb(II) ion-imprinted polymers and grafted onto the AA-CDI-NC surface (Pb(II)-MIP-NC). Meanwhile, Hg(II) ion-imprinted polymer was synthesized and grafted onto the AA-CDI-NC surface (Hg(II)-MIP-NC) using thymine as a functional monomer. The experimental results showed that Pb(II)-MIP-NC and Hg(II)-MIP-NC could effectively adsorb Pb(II) and Hg(II), respectively. Their adsorption behaviors for Pb(II) and Hg(II) were consistent with the secondary kinetic model and Langmuir adsorption isotherm model. The adsorption capacities of Pb (II)-MIP-NC and Hg (II)-MIP-NC for Pb (II) and Hg (II) were 27.55 mg/g and 161.31, respectively.