Surface modification of TiO2 nanoparticle by three dimensional silane coupling agent and preparation of polyamide/modified-TiO2 nanocomposites for removal of Cr (VI) from aqueous solutions

In the present investigation, the goal was the preparation, characterization and surface morphology of polyamide/modified-TiO2 nanocomposites (PA/m-TiO2 NCs). At first, a soluble aromatic PA was synthesized by direct polycondensation reaction of the synthesized diacid and 1,3-phenylenediamine in molten tetrabutylammonium bromide (TBAB) with good yield and moderate inherent viscosity. The structure and purity of these compounds were confirmed by different techniques. For the improvement of TiO2 nanoparticles dispersion and enhancing interactions between nanoparticles and polymeric matrix, the surface of TiO2 was successfully modified by 1,3,5-triazine based silane coupling agent. The functionalized nanoparticles were then inscribed in 0, 5, 10 and 15 wt.% into polymer matrix. The resulting hybrids were characterized by Fourier transform infrared spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA). The TGA of the obtained PA/m-TiO2 NCs proves the enhancement in the thermal stability with an increase in the percentage of titania nanoparticles. It was further investigated for Cr(VI) ion removal by optimizing the parameters including pH, contact time and concentration. Also, adsorption kinetics and adsorption isotherms of this polymer were investigated.