Preparation of Silicone Emulsion Defoamer with Easy Separation of Magnetic Hydrophobic Nanoparticles
Abstract To prepare lyophobic magnetic nanoparticles (LMNs) with core/shell structure to be applied in silicone emulsion defoamer, magnetic nanoparticles covered with silica (MNS) were prepared in a one step process from FeCl3 6H2O, FeCl2 4H2O and tetraethyl orthosilicate and then modified with poly (methylhydrosiloxane) X ray powder diffraction (XRD) scanning electron microscope (SEM) Fourier transform infrared spectroscope (FTIR) thermogravimetric analysis (TGA) and contact angle tests were performed to characterize the nano particles, and the droplets of the defoamer emulsion were observed with a microscope. The foam breaking and foam inhibition properties of the defoamer and the magnetic separation of the particles were observed and recorded by a camera. It was found that the silicone emulsion defoamer exhibited good foam breaking and foam inhibition properties for foaming systems with anionic, cationic and non ionic surfactants, respectively. The solid particles in the defoamer could be easily separated from the defoamed systems by a magnet.