The effects of magnetic nanoparticles embedded with SA/PVA and pH on chemical-mechanical polishing wastewater and magnetic particle regeneration and recycle

Experiments were conducted using sodium alginate (SA) and polyvinyl alcohol (PVA) as embedded materials for Fe3O4 magnetic nanoparticles (MNPs). The materials provided excellent protection to the embedded MNPs in low-pH conditions. This study observed and compared the adsorption capacity of the unaltered and embedded MNPs. At pH 3 and without additional magnetic fields, the wastewater turbidity removal rate of the embedded MNPs reached a maximum of 95%, similar to that of the unaltered MNPs. Moreover, this study examined the recyclability and reusability of the unaltered and embedded MNPs and discovered that the embedded MNPs could be reused up to seven times. Overall, the use of SA/PVA prevented MNPs from disintegrating and contaminating the wastewater through the dissolution of Fe ions. SA and PVA also increased the reusability of the unaltered MNPs.