Sensitive and environmental friendly sensor on porphyrin functionalized chitosan fiber membrane for Hg2+

Mercury is the most toxic and harmful heavy metal pollutant, and it is essential to detect and remove mercury from beverages. Inducing the porphyrin molecules into the chitosan structure, a novel membrane sensor tetrakis(4-carboxyphenyl)porphyrin-grafted chitosan fiber membrane (TCPP-CS) was prepared by electrospinning method and applied to recognize Hg2+ contaminant selectively. Compared with other common metal ions (Pb2+, Cu2+, Fe3+, Cr3+, Mg2+, and Zn2+), the colorimetric sensor has specific color development and sensitivity to Hg2+ and the detection limit of the sensor reaches 1 × 10−5 mol·L−1. The response time of the membrane is 5 s, and it can be specifically colored in various pH environments convenient for practical application. Hg2+ resulted in a visual color change of the fiber membrane from brown to yellow-green, indicating a potential interaction between the porphyrin-functionalized chitosan fiber membrane and Hg2+ ions, and the wavelength shift of the UV–visible spectrum can be observed. It has the advantages of simplicity, rapidity, high selectivity, and high sensitivity, providing a new method for removing and detecting heavy metals in traditional Chinese medicine and drinks.