Supramolecular cellulose-based heavy metal adsorbent for efficient and accurate removal of cobalt (II) for water treatment

Heavy metal ions' high toxicity, carcinogenicity, and non-degradability have been identified as the most severe environmental concerns. Therefore, in this study, a new type of cellulose-based ionic imprinting adsorbent (p-CMs@EPI@PEI@Cys-IIP) with a three-dimensional pore structure was developed to selectively adsorb cobalt (II) using a simple ion-cross-linking technique. In this experiment, p-CMs@EPI@PEI@Cys-IIP were prepared by modifying cellulose microspheres (p-CMs) with epichlorohydrin (EPI), polyethyleneimine (PEI) and L-cysteine (L-Cys).The p-CMs@EPI@PEI@Cys-IIP was found to be able to selectively adsorb Co (II), and it was well characterized with FT-IR, SEM, TGA, and XRD. The system adsorption experiment proved that the maximum adsorption capacity reached 158.93 mg g-1, below the pH 7. After five cycles, the adsorption capacity of p-CMs@EPI@-PEI@Cys-IIP still remained above 90%. The results of selectivity experiments indicated that p-CMs@EPI@PEI@Cys-IIP has preferential selectivity for Co (II). The adsorption isotherm and kinetic experiment of Co (II) conformed to the Langmuir model and pseudo-second-order kinetic, respectively. The adsorption process of Co (II) on p-CMs@EPI@PEI@Cys-IIP was also affected by the intra-particle diffusion model. Due to its simple preparation method and good adsorption performance, p-CMs@EPI@PEI@Cys-IIP would have a good application prospect in the selective removal of Co (II) for water treatment.

Automated summary

In this study, a new type of cellulose-based ionic imprinting adsorbent was developed for the selective removal of cobalt ions. The adsorbent exhibited excellent adsorption performance, high cycling stability, and preferential selectivity for cobalt ions. The simple preparation method and promising application prospects make it a promising candidate for water treatment.