[en] A functionalized organic-inorganic hybrid is synthesized by Mannich reaction after its activation with organosilane coupling agent and subsequent conjugation with and 1-napthyl-2-thiourea (ANTU). The material is characterized by fourier transform infrared spectroscopy, elemental and thermogravimetric analysis. Its efficacy as adsorbent is tested for the extraction of low level of mercury from aqueous solutions using radiotracer technique. Various parameters affecting mercury extraction are optimized. Maximum sorption (92%) of Hg(II) ions occured at pH 6 in 30 min using 50 mg of nanohybrid as extractant. In competitive environment only chromate and fluoride increased while thiosulfate reduced its extraction efficiency. The mercury adsorption process is chemisorption in nature and follows second-order kinetic model. The sorption follows Freundlich and D–R models over a wide range of concentration studied. The maximum uptake capacity of the material is 156.7 mmolg⁻¹. (paper)