Immobilization of NanoFe3O4 onto fabric material through in situ co-precipitation as a flexible catalyst for humic acid degradation

Abstract

Humic acid (HA) is a major component in dissolved natural organic matter (NOM) that is commonly found in natural water sources such as surface water and soil. Although HA is non-toxic, it is a precursor of carcinogenic and mutagenic disinfection by-products that will be generated when chlorine and chloramine are applied to disinfect water during the chlorination process. Hence, researchers have been investigating various strategies to remove HA from water sources and nanoparticles stood out as one of the preferred materials for the removal. However, owing to the tiny size of nanoparticles, the recycling, and removal of nanoparticles through sedimentation and centrifugation method is often time and energy-consuming. Therefore, this work set out to immobilize iron oxide nanoparticles (nanoFe3O4) onto fabric material to create a flexible catalyst that is feasible in degrading HA. The immobilization of nanoFe3O4 onto woven and non-woven fabrics was successfully done through in situ co-precipitation method. The flexible catalyst was found to be responsive to magnetic pull, which is one of the properties of nanoFe3O4 itself. On the other hand, scanning electron microscopy (SEM) images have verified the attachment of nanoFe3O4 was in an irregular pattern across the heterogeneous surface and it was grown on the fabric’s filament instead of being trapped between the pores of the fabric. Subsequently, the as-made flexible catalysts were tested and found to be feasible as it can degrade HA completely in 24 to 36 h. More importantly, the flexible catalyst can be removed easily in an instant with a negligible detachment of nanoparticles from the fabric material. While this preliminary result is promising, it is suggested that further study should be carried out to optimize the efficiency of this novel flexible catalyst on the degradation of HA.