Fluorescent cellulose hydrogels based on corn stalk of double sulfhydryl functional group modification for Hg(II) removal and detection.

Ions of mercury, one of the most hazardous heavy metals in nature, pose serious risks to the environment and human health. Blue sulfur-doped carbon dots (SCDs) from corn stalks were utilized as material. The SCDs were incorporated into a carboxylated hydrogel modified with sulfur, and a compound gel (SCDs-KTOCS gel) was successfully fabricated for simultaneous fluorescence detection and Hg(II) adsorption. This enabled the effective identification and removal of Hg(II) from contaminated water. The chemical content, fluorescence properties, and adsorption behaviors of the SCDs-KTOCS-gels were analyzed. The results demonstrate that the SCDs-KTOCS-gels exhibited effective Hg(II) adsorption (193 mg/g) and an extensive linear spectrum for Hg(II) fluorescence emission (150-500 mg/L; detection limit = 1.5668 mg/L). The adsorption values fit well with the Temkin models and pseudo-second-order kinetics. Additionally, Hg(II) detection and adsorption in the SCDs-KTOCS-gels were examined. By exchanging the existing probe for a suitable one that fits various relevant applications, this study suggests an environmentally friendly and sustainable method of producing materials for removing and detecting Hg(II) and constructing a fluorescence hydrogel for the detection and adsorption of different metals.