Dual function naphthalimide modified mesoporous silica for organic pollutant sensing and removal from water

Dual-function materials for the selective sensing and adsorption of multiple dyes simultaneously are still challenging to prepare. Herein, a naphthalimide functionalized SBA-15 fluorescent sensor and adsorbent, namely, TPNI-SBA-15, was developed for the simultaneous detection and adsorption of the anionic dye congo red (CR) and the cationic dyes methylene blue (MLB) and malachite green (MG). The fluorescence intensity of TPNI-SBA-15 at 531 nm selectively quenched by CR, MLB and MG. The detection of CR was based on inner filter effect mechanism, and the detection of MLB and MG was attributed to the combined mechanism of electrostatic interaction, electron transfer and fluorescence resonance energy transfer. Limits of detection of 0.03, 0.10 and 0.26 mu M, and limits of quantification of 0.10, 0.33 and 0.85 mu M were estimated for the determination of CR, MLB and MG, respectively. The satisfactory recoveries from 99.72 to 104.80 % were acquired for detecting CR in tap water, with a relative standard deviation less than 2.9 %. Moreover, TPNI-SBA-15 can selectively remove CR, MLB and MG from water with a removal percentage reaching 100 %, 98.8 % and 61.5 %, respectively, within 1 min. TPNI-SBA-15 exhibited good dye adsorption and removal stability after three cycles of adsorption, desorption and regeneration. TPNI-SBA-15 also removes CR, MLB and MG from binary, ternary and quaternary dye mixtures conveniently and effectively. This work provided an economic strategy to realize simultaneous selective detection and adsorption of organic dyes by rationally introducing specific organic functional units into mesoporous structures. (c) 2022 Elsevier B.V. All rights reserved.