Synthesis of SiO2/Fe3O4 magnetic nanoparticles as a nano-coagulant/flocculant for removal of calcium fluoride in semiconductor wastewater

Abstract

In this study, the novel SiO2/Fe3O4 magnetic nanoparticles (MNPs) were synthesised and used as a nano-coagulant/flocculant for removal of suspended CaF2 in semiconductor wastewater. Different batches of SiO2/Fe3O4 MNPs were synthesised using the sol-gel method using various dosages of tetraethyl orthosilicate (TEOS) and FESEM results revealed that the TEOS dosage has a significant impact on the particle size of the synthesised SiO2/Fe3O4 MNPs. In particular, the batch of SiO2/Fe3O4 MNPs synthesised using 2 mL of TEOS has an average particle size of 190 nm, and when used as a nano-coagulant/flocculant, it was able to effectively remove 99 % of total suspended solids (TSS) from semiconductor wastewater. In addition, the SiO2/Fe3O4 MNPs were further characterized using energy dispersive X-ray (EDX), transmission electron detector (TED), and X-ray diffraction (XRD) analysis. Considering the promising 99 % TSS removal synthesised SiO2/Fe3O4 MNPs and its superparamagnetic properties, the SiO2/Fe3O4 MNPs may be used as a novel nano-coagulant/flocculant for the removal of suspended CaF2 in semiconductor wastewater.