Facile synthesis of manganese oxide modified lignin nanocomposites from lignocellulosic biorefinery wastes for dye removal.

Abstract

In this study, a facile method to prepare MnO2 nanodots modified lignin nanocomposite (MnO2@LNP) was developed for efficient dye removal. The MnO2@LNP displayed hierarchical spherical nanostructures, where the MnO2 nanodots were evenly dispersed within the lignin nanosphere. Compared with lignin nanoparticles, the as-prepared MnO2@LNP exhibits higher surface area and can be separated after adsorption. It showed excellent adsorption capacity (806 mg/g) towards a typical cationic dye, methylene blue (MB), at a fast removal rate, where more than 80% of adsorption capacity was reached within 5 min at room temperature. The high adsorption capacity was contributed by the high surface area and negative charge on the adsorbent. The adsorption process is pH-responsive and exothermic, and the spent adsorbent can be reused for at least five cycles. This study displayed an efficient method to prepare MnO2@LNP for the high-value utilization of lignin-derived from lignocellulosic biorefinery.