Sulfhydryl-functionalized anisotropic photonic crystal hydrogels for visual Hg2+ detection and adsorption in cinnabar mine water area

Emissions of mercury ions from human activities during mining and smelting processes cannot be overlooked due to their potential for environmental pollution. Consequently, developing a material that offers both visual detection capability and efficient adsorption for Hg²⁺ is crucial. Inspired by cephalopod skin, we have prepared a sulfhydryl-functionalized anisotropic photonic crystal hydrogel (PDGI/PAAm-SH). The bilayer structure of polydodecyl glyceryl itaconate (PDGI) is immobilized and stabilized within the sulfhydryl-functionalized polyacrylamide network after polymerization. The porous structure of hydrogel facilitates the adsorption of Hg²⁺ in solution, resulting in a blue shift in structural color, which allows for visual detection. The PDGI/PAAm-SH effectively adsorbs and removes Hg²⁺ from water, with an impressive uptake capacity of 129.06 mmol kg^-1. Additionally, this hydrogel exhibits good reproducibility, excellent mechanical properties, and remarkable selectivity for Hg²⁺. It can shield interference from other ions during detection and shows promising applications in environmental monitoring and purification.