Nanocellulose-based hydrogel incorporating silver nanoclusters for sensitive detection and efficient removal of hexavalent chromium

Chromium pollution is a significant environmental threat. As a result, effective and multifunctional adsorbents for removing hexavalent chromium [Cr(VI)] ions are urgently needed. A new nanocellulose-based hydrogel (NBH) based on silver nanoclusters was created in this work for the sensitive detection and removal of Cr(VI). This NBH was characterised with respect to its morphological features, chemical composition, optical properties, and sorption and detection characteristics and so on. The NBH adsorption isotherm followed the Langmuir model well, and the predicted maximum adsorption capacity was 418.5 mg/g. Kinetic study revealed that Cr(VI) sorption followed the pseudo-second-order kinetic model. Regeneration studies showed the efficiency of more than 85%, even after four adsorption–desorption cycles. The NBH displayed high selectivity and sensitivity to Cr(VI), with a detection limit of 0.43 μg/L. Then, the mechanism analysis of the NBH for the sensitive detection and effective removal was discussed. Furthermore, a cost-of-fabrication study found that NBH was about six times less expensive than commercial activated carbon for removing Cr(VI) ions. This research suggests a new cellulose-based approach for creating a low-cost, multifunctional adsorbent for removing Cr(VI) ions.