Colorimetric sensing for the sensitive detection of UO 2 2+ via the phosphorylation functionalized mesoporous silica-based controlled release system.

In this study, we developed a simple and sensitive colorimetric sensing method for the detection of UO 2 2+ , which was built to release MB from the molybdenum disulfide with a phosphate group (MoS 2 -PO 4 ) gated mesoporous silica nanoparticles functionalized phosphate group (MSN-PO 4 ) with UO 2 2+ chelating. In the presence of UO 2 2+ , MoS 2 -PO 4 can be effectively adsorbed onto the surface of MSN-PO 4 based on the coordination chemistry for strong affinity between the P-O bond and UO 2 2+ . The adsorbed MoS 2 -PO 4 was then utilized as an ideal gate material to control the release of signal molecules (MB) entrapped within the pores of MSN-PO 4 , resulting in a detectable decrease in the absorption peak at 663 nm. This colorimetric sensing demonstrated the advantages of simplicity and easy manipulation and exhibited a linear response to the concentration of UO 2 2+ within the range of 0.02-0.2 μM. The detection limit of UO 2 2+ was determined to be 0.85 nM, which was lower than the limit (130 nmol L -1 ) set by the US Environmental Protection Agency. Furthermore, the proposed colorimetric sensing method has been utilized to determine UO 2 2+ in samples of Xiangjiang River and tap water, and a high recovery rate was achieved. This method shows promising potential in preventing and controlling environmental pollution.