Carbon dots-MnO2 nanocomposites for As(III) detection in groundwater with high sensitivity and selectivity
As(III) pollution has attracted increasing concerns due to their vital role in environmental safety and human health. Carbon dots (CDs)-MnO2 nanocomposites were prepared and characterized for As(III) detection. The intense blue fluorescence of CDs can be greatly quenched due to the functionalization of MnO2 nanosheets due to the existence of fluorescence resonance energy transfer (FRET) effect. CDs-MnO2 nanocomposites were then used as a fluorescence sensor for As(III) detection with high detection sensitivity and selectivity. The redox reaction between As(III) and MnO2 nanosheets can induce the decomposition of MnO2 and termination of FERT process. Then the blue fluorescence originated from CDs can be recovered. The detection limit of CDs-MnO2 nanocomposites toward As(III) was calculated to be 16.8 nM (1.40 ppb) in a linear concentration range of 0-200 nM. CDs-MnO2 nanocomposites were also investigated to possess highly selective ability toward As(III) detection. In addition, the spiked and recovery test also confirmed the practicality and reliability of CDs-MnO2 nanocomposites toward As(III) detection in the real water samples, such as groundwater etc. Our research has provided reliable tool and strategy for visual detection of As(III) with outstanding sensing ability.