Influence of zeta potential of ZrO2 and Al2O3 nanoparticles on removal of metal ions by hybrid electrospun polyamide 6 membrane: Kinetics of adsorption and fouling mechanisms

Electrostatic charging of the adsorbent is a critical method for the selective removal of metal ions fromacidic wastewater. In this study, electrospun polyamide 6 (PA6) membranes were separately incorporated with Al2O3 and ZrO2 nanoparticles (NPs), and their ability in the removal of cations (eg, Al3+ and Fe3+) were evaluated by static adsorption and filtration methods. The impact of various parameters, namely microstructure, surface porosity, functional molecular groups, and hydrophobicity of membranes on the removal process, was investigated. By evaluating the zeta (ζ) potential of oxide ceramic NPs, it was found that the Al2O3 and ZrO2 NPs had positive and negative electrostatic charges inacidic solution, respectively. The results showed that the incorporation of negatively charged ZrO2 NPs improved both the static adsorption and filtration removal capability of the PA6 membrane. The maximum adsorption efficiency of Al3+ and Fe3+ cations was 52.43% and 54.11%, and the highest filtration efficiency of the mentioned cations obtained by electrospun hybrid ZrO2 incorporated PA6 membrane was 98.6% and 99.3%, respectively. It was also found that the adsorption of both Al3+ and Fe3+ cations correlated well with the pseudo‐second‐order kinetic model. The results also demonstrated that the dominant blocking models were switched with the increase in the initial concentration of metal ions from 5 ppm‐70 ppm. Incorporation of ceramic NPs (eg, ZrO2) into PA6 scaffold improves the removal of Al3+ and Fe3+ cations due to the negative electrostatic charges.