Wood-derived nanocellulose hydrogel incorporating gold nanoclusters using in situ multistep reactions for efficient sorption and sensitive detection of mercury ion

• A novel wood-derived nanocellulose hydrogel with gold nanoclusters was prepared. • This hydrogel simultaneously has effective adsorption and detection abilities. • Maximum sorption capacity of this hydrogel for Hg(II) ion reached 234.4 mg/g. • The hydrogel had sensitive detection ability with the detection limit of 0.09 μg/L. • Electrostatic, metallophilic and complexation interactions worked for sorption. A wood-derived nanocellulose hydrogel (WNH) with gold nanoclusters (Au NCs) was prepared by in situ multistep reactions, which was used as an effective adsorbent for the adsorption of mercury ion (Hg 2+ ) and a solid-state fluorescent probe for detecting Hg 2+ . The WNH’s morphology, chemical structure and optical properties were investigated. The adsorption performance of WNH towards the Hg 2+ ion was studied, indicating that the sorption data were well fitted by Langmuir and pseudo-second-order models with a maximum sorption capacity of 234.4 mg/g. The detection performance of WNH towards the Hg 2+ ion was also investigated, showing excellent selectivity and sensitivity to Hg 2+ with a detection limit of 0.09 μg/L. The 3D porous structure created by wood-derived nanocellulose increased adsorption and detection, according to the mechanism analysis. Furthermore, a cost analysis was performed for WNH and commercial activated carbon, and the results showed that WNH was the economically viable option for Hg 2+ sorption. This research could pave the way for a low-cost, multi-functional and environmentally friendly mercury adsorbent.