Alkali resistant nanocomposite gel beads as renewable adsorbents for water phosphate recovery

• Published in: The Science of the total environment 2019-10, Vol.685, p.10-18
• Main Authors: Huang, Xuanqi, Wu, Wufeng, Xia, Yan, Li, Wanbin, Gong, Yanyan, Li, Zhanjun
• Format: Article
• Language: English
• Subjects: Alginate; Gel beads; Hydrous zirconium oxide; Nanomaterials; Phosphate recovery
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2019.05.296

Hydrous zirconium oxide (HZO) encapsulated alginate gel beads were synthesized for phosphate recovery from water. Importantly, we find that HZO/alginate gel beads (ZrA) crosslinked with Ca2+, Mg2+, Fe3+, Al3+, and Zr4+ are unstable under an intense alkali regeneration condition. Only Sr2+-crosslinked ZrA can endure a high alkali solution. ZrA possesses a high specific surface area (80.84 m2·g−1) and a mesoporous structure (15.3 nm and 0.196 cm3·g−1), which endow them with a high Langmuir adsorption capacity of 52.5 mg-P/g. ZrA can be easily recycled, and the mass loss of HZO is prevented. Furthermore, the strontium alginate gel framework protects the encapsulated HZO nanoparticles from adverse humic acid contamination. ZrA can be regenerated for at least 5 adsorption/desorption cycles. Cost analysis indicates the potential scale application feasibility for ZrA. This study provides a novel, simple, and environmentally benign solution to immobilize HZO for efficient phosphate recovery. [Display omitted] •Hydrous zirconium oxide/alginate beads (ZrA) are prepared for phosphorus recovery.•Sr2+ is the only crosslinking ion that can produce alkali resistant ZrA beads.•ZrA is mesoporous (15.3 nm) with a specific surface area of 80.84 m2·g−1.•ZrA shows a high Langmuir adsorption capacity to phosphate (52.5 mg-P·g−1).•ZrA can be easily recycled and protected from adverse humic acid contamination.