Grafting of organosilane derived from 3-glycidoxypropyltrimethoxysilane and thiourea onto magnesium phyllosilicate by sol–gel process and investigation of metal adsorption properties

A layered inorganic–organic magnesium silicate (Mg-GTPS-TU) has been successfully synthesized by using sol–gel based precursor under mild temperature conditions and a new silylaing agent (GTPS-TU) derived from 3-glycidoxypropyltrimethoxysilane (GTPS) and thiourea (TU) as the silicon source. The hybrid material was characterized through elemental analysis, infrared spectroscopy, X-ray diffractometry, thermogravimetry, and carbon and silicon solid-state nuclear magnetic resonance spectroscopy. The result confirmed the attachment of organic functionality to the inorganic silicon network. The inter-lamellar distance for the hybrid material was found to be 18.8 Å. Metal adsorption characteristics follows Cr(III) >Mn(II)>Zn(II) with more affinity towards Cr(III) in dilute aqueous solution. Evaluation of thermodynamic parameters ΔH and ΔS for Cr(III) were found to be 25.44 J mol−1 and 79.9 J mol−1 K−1, respectively, indicating adsorption process to be endothermic in nature. The negative value of ΔG indicated the feasibility and spontaneity of ongoing adsorption process at relatively higher temperature. The presence of multiple coordination sites in the attached organic functionality expresses the potentiality of the hybrid material containing new silylating agent for heavy cation removal from eco-system.