Functionalization of Silica Coated on Iron Sand Magnetic Material with Diethylenetriamine

Abstract

Diethylenetriamine (DETA) functionalized silica coated on magnetic material of iron sand (MM@SiO2-DETA) has been synthesized by sol-gel method. Synthesis was carried out by coating magnetic material of iron sand as the core with diethylenetriamine-modified silica using sodium silicate solution and N 1 -(3-trimethoxysylilpropyl)diethylenetriamine (TMPSDETA) as silica and diethylenetriamine group sources, respectively. Several variations of mole ratio of silica to DETA at a constant weight of magnetic material were examined to evaluate the effect of the coating agent amount on the properties of MM@SiO2-DETA. MM@SiO2-DETA was characterized with Fourier transform infrared spectrophotometer, X-ray diffraction, scanning electron microscope with energy dispersive spectroscope (SEM-EDX), vibrating sample magnetometer and thermal gravimetric analysis. Stability test of product toward acidic solution and the effect of mole ratio of SiO2 and DETA on adsorption of Au(III) also evaluated. The characterization results indicated that SiO2 and DETA groups were successfully attached to the surface of magnetic material to form MM@SiO2-DETA. Characteristic bands of the vibration of propyl and amino groups derived from DETA; indicating that DETA was successfully reacted with MM@SiO2. Coating of magnetic material with SiO2 exhibits the decrease in Ms up to 38.2 emu/g and 23.5 emu/g after coating with SiO2-DETA. Thermalgravimetric analysis indicate thermal stability of the resulted product of MM@SiO2-DETA (1:1) up to 350 °C. Dissolution by acid solution can be diminished by coating magnetic material with silica. Gold(III) adsorption capacity of MM@SiO2-DETA (1:0.5), MM@SiO2-DETA (1:1) and MM@SiO2-DETA (1:2) are found to be higher than 92 %.