STUDY ON THE PREPARATION AND CHARACTERIZATION OF MAGNETIC FLUID COMPOUND FLOCCULANT

Magnetic fluid (MF) flocculant was prepared by solgel method and characterized. Its flocculation efficiency was compared with a magnetic seed compound flocculant and studied by flocculation tests. The forces affecting flocculant particles under an external magnetic field were researched. The results showed that, when coated with SiO sub(2) and PAM as double-layer, magnetic fluid compound flocculant was stable to exist in solution. The structure of the particles observed by SEM showed that they were well polydisperse with a smooth surface. The magnetic flocculation efficiency of magnetic fluid compound flocculant was obviously superior to that of the magnetic seed compound flocculant. The removal rates of colour reached 85.7 and 86.1% as maximum values when V sub(MF)V sub(PAM) was 10 and concentration of PAC was 0.4 mol/L, respectively. Meanwhile, the removal rates of TSS, TP, COD and colour reached 95.8, 90.2, 83.7 and 85.7%, respectively, when the magnetic field strength was 200 mT, and the external forces dominated in the process of flocculation.