Facile preparation of lignosulfonate-based superparamagnetic colloidal nanocrystal clusters (CNCs)

Colloidal nanocrystal clusters (CNCs) are hierarchical nanostructure formed by clustering several nanocrystals into one nano-ensemble. In this work, novel lignosulfonate (LS)-based superparamagnetic CNCs were prepared for the first time. The strategy based on electrostatic interaction between LS, nanocrystals and charge control agent, and included multistep of surface modification, precipitation and self-assembly. With the protection of LS and blocking of CTAB, individual gamma-Fe2O3 nanocrystals in the colloidal particles can keep monodisperse to form the cluster morphology. The superparamagnetic gamma-Fe2O3 endowed superparamagnetic property to the CNCs, and the saturation magnetization value of CNCs increased with the increase number of nanocrystals in the LS spheres. Furthermore, the LS-based superparamagnetic CNCs showed excellent dye adsorption efficiency for different dyes, especially for positive charged cationic dyes.

Automated summary

The study presents a novel method for preparing LS-based superparamagnetic CNCs through electrostatic interaction and multistep surface modification. The protection of LS and blockage of CTAB led to well-dispersed individual gamma-Fe2O3 nanocrystals and a superparamagnetic property in CNCs. Moreover, LS-based CNCs exhibited excellent dye adsorption efficiency towards cationic dyes.