1-[(2-Hydroxy-phenylimino)-methyl]-naphthalen-2-ol: application in detection and adsorption of aluminum ions

A novel on-off Al3+ ions fluorescence-enhanced sensor (E)-1-(((2-hydroxyphenyl) imino)methyl)naphthalen-2-ol (AH-2) and its hydrogel hybrid (PAMN) were synthesized. AH-2 showed excellent selectivity and ultrasensitive to Al3+ ions; the detection limit was 2.36 x 10(-9) M. The most plausible complexation mechanism was studied by H-1 NMR, FT-IR, HR-MS, Job's plot and theoretical calculation. And, it was interesting that PAMN could adsorb Al3+ ions with a removal rate of over 99%, which also could easily be distinguished by the naked eye in UV lamp (365 nm). Before and after adsorption of Al3+ ions, the microstructures of PAMN were analyzed by scanning electron microscope and X-ray energy spectrometer. The silica gel detect plates prepared in this work could rapidly and conveniently detect Al3+ ions with a concentration greater than 5 x 10(-6) M (0.13 mg/L) in aqueous solution, and the detection concentration (0.13 mg/L) was lower than the national standard concentration of Al3+ ions (0.2 mg/L) in city tap water of china.

Automated summary

The newly synthesized sensor AH-2 showed high selectivity and sensitivity to Al3+ ions, while the hydrogel PAMN exhibited excellent adsorption performance and the ability to visually distinguish adsorbed Al3+ ions.