Simultaneous visual detection and removal of lead(II) ions with pyromellitic dianhydride-grafted cellulose nanofibrous membranes

By virtue of the affinity of pyromellitic dianhydride (PMDA) for lead(II) ion (Pb2+) and the inherent structural merits of electrospun nanofibrous membranes, a novel solid-phase nanofibrous material was facilely fabricated via the modification of deacetylated cellulose acetate membranes with PMDA (DCA-PMDA). The resultant DCA-PMDA can be applied for the simultaneous naked-eye detection and removal of Pb2+ from water matrixes by simple filtration followed by treatment with Na2S solution. Importantly, the color of the DCA-PMDA changes from white to dark yellow-brown due to the formation of PbS, which can be leveraged for the colorimetric detection of Pb2+ by the naked eye with a detection limit of 0.048 μM. Under the same circumstances, the maximum adsorption capacity was determined to be as high as 326.80 mg g-1. Furthermore, the extraction of Pb2+ from DCA-PMDA was possible with HNO3. The regenerated membrane that remained maintained the high sensitivity to Pb2+ and exhibited almost the same adsorption capacity as the original membrane. Therefore, the proposed membrane offers a cost-effective material that can be considered as a viable alternative for effectively detecting and removing toxic Pb2+ from water samples.