Spinach-extracted chlorophyll-a modified peanut shell as fluorescence sensors for selective detection of Hg2+ in water

A prototype of environmentally friendly and low-cost fluorescence sensor, consisting of spinach-extracted chlorophyll-a modified alkali-treated peanut shell (denoted as chlorophyll-a@peanut shell), is achieved and used for trace detection of Hg2+ in aqueous solutions through fluorescence quenching method. The chlorophyll-a@peanut shell exhibits a linear dynamic detection range from 0 to 19 × 10−8 M for Hg2+ with a detection lower limit of 8.5 × 10−9 M. The feasibility of sensitive and selective detection of Hg2+ using the chlorophyll-a@peanut shell is also demonstrated in the test of Hg2+ in synthetic polluted lake waters, showing excellent anti-interference ability to common impurities like silt and alga. Further experiments demonstrate that the improved sensing property of the chlorophyll-a@peanut shell for Hg2+ than that of chlorophyll-a in solution is ascribed to the selective Hg2+ adsorption of the alkali-treated peanut shell, which might also be used for the remediation of Hg2+ in polluted waters. The design concept using non-toxic plants may open a new door to the environmentally friendly and low-cost materials for detection and remediation of environmental pollutants.