Factors affecting the physicochemical properties of the modified core/shell NH2–SiO2@NZVI nanoparticles

A novel core–shell amino-functionalized silica coated nanoscale zero valent iron (NH 2 –SiO 2 @NZVI) was prepared by the combination of liquid phase reducing method and improved Stöber method. The surface, structure and characteristics of the nanoparticles (NPs) were investigated by transmission electron microscope (TEM), scanning electron microscopy (SEM), powder X-ray diffraction (XRD), and the elemental analysis. It was found that the appropriate dropping rate of NaBF 4 and the proper usage of 3-aminopropyl trimethoxysilane (APTMS) were the crucial and key step for the formation of highly uniform and desirable NH 2 –SiO 2 @NZVI particles. SEM, XRD results showed that the obtained NH 2 –SiO 2 @NZVI NPs has a good dispersibility and antioxidant capacity with the particle size around 120   nm, BET surface area around 123.38   m 2 /g when NaBH 4 dropping speed was 1   ml/min and the usage of APTMS was 0.3   ml/ml tetraethyl orthosilicate (TEOS). NH 2 –SiO 2 @NZVI particles can effectively adsorb TCP with the first-order rate constant k obs of 0.0204   h −1 in 18   h and remove with a removal efficiency of 45.62% in 48   h.