ABSTRACT
Simultaneous removal of phosphorus (P) and algae is important to mitigate eutrophication, however, it is rather challenging in remediation of harmful algal blooms (HABs)-contaminated water. In this study, a wet alginate bead functionalized by CaO2 particle formed layer by layer was prepared with an in-situ method and optimized to remove phosphorous and inhibit algae growth. The stable H2O2 release with a concentration level of 0.06 mM was observed for a period of 26 d. The content of peroxy groups (-O-O-) in the optimal bead was 0.44 mmol·g-1 through permanganate-based titration study. For solution with an initial phosphorous concentration of 10 mg·L-1, the removal was around 97% in pH 3.0-10.0. XRD, SEM, and XPS studies and kinetic modelings showed that removal of phosphorus was mainly due to formation of insoluble Ca-P compounds in the bead. The CaO2-functionalized bead inhibited algae growth with an effect lasting over 170 d, which was much better than liquid H2O2 and Ca(OH)2 bead; the phosphorous removal with an efficiency of about 70% was simultaneously obtained. Furthermore, the bead demonstrated to be effective in removing algae in the realistic water from a reservoir. In summary, this study shows that the CaO2-functionalized material is promising for simultaneous removal of phosphorous and management of HABs.
