Thioacetamide (TAA), a well known ligand having both S and N donors, has been immobilized quantitatively onto silica gel (SG) surface for easy detection (through naked eye) and removal of mercury (Hg) from environmental samples for the first time. The quantitative immobilization involves direct incorporation of TAA onto SG without widely used Mannich reaction. TAA immobilized SG (TAA@FSG) has been characterized by spectral, morphological, elemental, thermal, chemical and electrochemical analysis. The TAA@FSG has a BET surface area of 243.31m2g−1 with an average pore diameter of 3–7nm. The degree of immobilization (α=∼9.45μmolm−2) is quantitative. The role of TAA in detecting and removing Hg has been elucidated. Trace level of Hg (below 0.01mgL−1) has been detected through naked eye. The Hg2+ binding capacity of the synthesized material is found to be 17.5mgg−1 even at very low level of Hg (Co=100mgL−1). The developed method may be used to remove Hg from real samples.