Selective and quantitative recovery of sulfadiazine from seawater by Sb doped LTA zeolite electrochemical sensor

The sensitive Sb probe has been anchored in the LTA (Linde Type A) zeolite to form a bifunctional sensor for the electrochemical detection and recycling of sulfadiazine (SDZ) in seawater. Under Amperometric i-t Curve (A i-t C) method, SDZ is quantitatively adsorbed on the Sb LTA zeolite electrode from seawater by adjusting the reduction time and potential. Under differential pulse voltammetry (DPV) method, a characteristic peak is observed at ca. 0.80 V whose intensity can indicate the SDZ concentration on the novel modified electrode. Also, SDZ can be selectively released to phosphate-buffered saline (PBS) in the potential range of 0.80–0.95 V. The electrochemical mechanism of the reversible recovery reaction is carefully studied by the cyclic voltammetry (CV) method and confirmed by the X-ray Photoelectron Spectroscopy (XPS) analysis results related to the interaction between the electrode material and SDZ before and after electrochemical process. Sb doped on LTA zeolite presented a cubic phase from SEM images, and there are some SDZ particles accumulated and adsorbed on the surface of the crystal from TEM images. Theoretical calculation results reveal that SDZ is stable in the electrochemical adsorption and desorption process due to the interaction between the SDZ molecules and the 8-ring opening windows of LTA zeolite framework. The transfer efficiency of SDZ could reach 9.62 μg / 100 s or 0.430 g / 1 g based on the mass of Sb probe. The multifunctional sensor suggests a novel strategy for the electrochemically controlled detection and recovery toward antibiotic sulfadiazine.