Highly Efficient Removal of Phosphate by Film-like Purifier Prepared via Dopamine-Assisted Fixation of Lanthanum Hydroxide onto Bacterial Cellulose

Abstract

Eutrophication caused by excess phosphate is a growing threat to aquatic ecosystems, driving the need for efficient and practical removal technologies. Lanthanum (La)-based adsorbents are of significant interest due to their high affinity for phosphate, structural tunability, and efficient metal utilization. In this study, we developed a flexible, film-like composite adsorbent by uniformly anchoring La(OH)3 nanoparticles onto a 3D bacterial cellulose nanofiber network using a dopamine-assisted approach. The resulting composite achieves nearly complete phosphate removal (∼100%) at concentrations below 10 mg/L, while retaining high efficiency over a broad pH range and in complex aqueous conditions. Notably, it also exhibits exceptional La utilization and a phosphate adsorption capacity higher than most previously reported powder-based adsorbents. The flexible film-like architecture offers the critical practical advantages of easy handling and separation from treated water. This work demonstrates a rational integration strategy for fabricating a flexible film adsorbent that achieves high La utilization efficiency and practical operability for targeted low-concentration phosphate removal in water treatment.