Sepiolite functionalized with N-[3-(trimethoxysilyl)propyl]ethylenediamine triacetic acid trisodium salt. Part I: Preparation and characterization

Abstract

Natural sepiolite from Andrici (Serbia) was functionalized by covalent grafting of N-[3-(trimethoxysilyl)propyl]ethylenediamine triacetic acid trisodium salt onto the Si-OH sepiolite groups. The functionalized material, MSEAS, was characterized by determination of the phase composition by X-ray diffraction (XRD) analysis, analysis of the morphological characteristics by scanning electron microscopy (SEM), using Fourier transform infrared (FTIR) spectroscopy, differential thermal analyses (DTA), determination of the specific surface areas and pore size distribution using the BET method and point of zero charge (pH(pzc)) determination. The crystal structure of sepiolite did not change significantly upon surface modification. The FT-IR and DTA analyses confirmed that the modified sample maintained the basic structure of sepiolite and the presence of organic groups in the functionalized sepiolite sample. The point of zero charge of MSEAS in KNO3 solutions of different concentrations, determined by the batch technique, was at pH 7.0 +/- 0.1.