Novel BODIPY-based fluorescent Lycopodium clavatum sporopollenin microcapsules for detection and removal of Cu(II) ions

In this study, microcapsules of L. clavatum sporopollenin (f-sporopollenin) immobilized with BODIPY were developed. XRD, SEM, and FTIR did characterization of f-sporopollenin, showing that the BODIPY dye was successfully introduced, and the microcapsule structure of f-sporopollenin microcapsules was well preserved after the post-grafting procedure. When Cu(II) was added to the f-sporopollenin suspension, the fluorescence intensity gradually decreased at ~541 nm. Furthermore, adding Cu(II) to suspension mixtures in the presence of other cations resulted in dramatic fluorescent quenching, which showed that it was excellent selectivity for Cu(II) ions. The linear detection range for low concentration Cu(II) detection was 1 – 10 µM, and the detection limit was 7.41 × 10−7 M (0.741 µM). Prepared f-sporopollenin was also used as an adsorbent to remove Cu(II) ions from aqueous solutions. The adsorption study showed that the optimum adsorption conditions were pH = 6.0, amount of adsorbent 0.04 g, initial Cu(II) concentration at 25 mg/L, and contact time of 120 min. Adsorption isotherms and kinetics have been studied and found to fit the Langmuir isotherm model and the pseudo-second-order kinetic. The theoretical maximum Langmuir adsorption capacity of Cu(II) towards f-sporopollenin was 22.71 mg/g. Therefore, f-sporopollenin shows promise for removing and detecting Cu(II) ions in water.