Repurposing lignin to generate functional afterglow paper

Lignin is a significant byproduct from the pulp and paper industry. However, the conversion of lignin to a resource with added value is plagued by expensive processing. Here we report that the syringyl units (S) of sodium lignosulfonate (LS) exhibit phosphorescence in water with a lifetime of similar to 2 ms and the lifetime can be prolonged up to similar to 618 ms by encapsulation in Ca-3(PO4)(2) due to the formation of H-type dimers of the S units (LS@Ca-3(PO4)(2)). Motivated by this, we develop afterglow paper through the in situ generation of LS@Ca-3(PO4)(2) in the paper matrix. The afterglow emission of the paper is sensitive to H2O2, enabling its application as a sensor for liquid/vapor H2O2. Moreover, the afterglow paper is shown to be suitable for use in anti-counterfeiting applications, enabling the development of a more sustainable pulp and paper industry.

Automated summary

In this study, the phosphorescence of the syringyl units of sodium lignosulfonate in water was investigated, and their lifetime was prolonged by encapsulation. The findings were applied to the development of afterglow paper, H2O2 sensor, and anti-counterfeiting applications.