On the basis of high selective and sensitive interaction of 1,8-naphthalimide with Hg2+ and the formation of stable neutral imide-Hg-imide complexes, we designed and synthesized a novel magnetic fluorescent sensor (S1) employed Fe3O4 magnetic nanoparticles and 1,8-naphthalimide fluorescent sensor. Under optimum conditions, S1 exhibits the high selectivity toward Hg2+ over other metal ions, with the detection limit of 1.03 x 10(-8) M. We demonstrated that a reliable fluorescence response of S1 toward Hg2+ over a broad pH range (pH = 5.0-9.0) could be reused at least four cycles. The maximum sorption capacity of S1 was about 5.6 mg g(-1). In addition, the removal of Hg2+, in water was achieved by the aggregation-induced sedimentation (AIS) strategy. Moreover, the suspended magnetic nanoparticles could be removed by external magnetic field, and the secondary pollution was avoided. The above-mentioned results indicate that this approach may serve as a foundation of the preparation of the multifunctional magnetic fluorescent sensor for simple, rapid, and simultaneous determination and removal of trace Hg2+ and other pollutants in environmental samples. (C) 2012 Elsevier Inc. All rights reserved.