Due to natural agents and human activities, large quantities of microplastics enter the marine environment. As an emerging pollutant, MPs have attracted worldwide attention and become a great challenge in recent years. Sodium alginate is a kind of natural polysaccharide with non-toxic, stability, and low cost. In this study, sodium alginate sponge was prepared by secondary freeze-drying technology. Alginate sponge contains a large number of hydrophilic groups; thus, alginate sponge has super water-absorbed (the water absorption rate range from 1193-5232%). Meanwhile, the alginate sponge has high porosity of 81.93% and excellent mechanical properties. The removal efficiency of 100 mg·L-1 microplastics by alginate sponge reached up to 92.3%. The 1 mg·L-1 and 10 mg·L-1 microplastics can be completely absorbed in 27 h and 60 h, respectively. The adsorption mechanism of microplastics adsorbed onto alginate sponge included intra-particle diffusion, hydrogen bonds interactions, and π-π interactions. In addition, the adsorption of MPs loaded Cu2+/Na+ by sponge in complex aqueous environments is still significant. This study expands the development prospect of sodium alginate sponge materials in the field of water treatment and provides a new green approach for the removal of microplastics.
Keywords: Adsorption; Chemical crosslink; Freeze-drying; Microplastics; Sodium alginate sponge.
© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.