A chitosan-based sensing membrane for on-site and sensitive dual-channel portable detection and efficient adsorption of Pb2+in groundwater

The presence of lead ion (Pb2+) in groundwater poses a serious risk to human health, even at low levels. Therefore, it is essential to develop a new strategy for both selective detection and effective removal of Pb2+ in groundwater, which has been rarely reported. Here, we developed a multi-functional chitosan-based fluorescent sensing membrane (CM-L/CG) by using a casting method for the sensitive/selective detection and removal of Pb2+ in groundwater. The CM-L /CG membrane can be integrated into the portable laser-induced fluorescence spectrometer (LIFs) for on-site detection of Pb2+, with a low detection limit of 1.02 ppb. Moreover, the CM-L/CG membrane demonstrates an outstanding 99 % removal rate and an adsorption capacity of 247.6 mg g-1 for Pb2+ and the adsorption process is mainly controlled by chemisorption. Importantly, the CM-L /CG membrane enables the real-time and on-site detection of Pb2+ in groundwater samples via a smartphone-based RGB (Red Green Blue) color analysis-assisted portable platform and portable LIFs-based platform, achieving acceptable results. This dual-functional fluorescent sensing membrane represents a breakthrough in environmental monitoring technology, offering a comprehensive solution for sensitive detection and efficient removal of Pb2+ from groundwater.