NUS Environmental Research Institute, National University of Singapore, 5A Engineering Drive 1, #02-01, Singapore 117411, Singapore.
Department of Civil and Environmental Engineering, National University of Singapore, Kent Ridge Crescent, Singapore 119260, Singapore; School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China.
Sci Total Environ. 2022 Feb 1;806(Pt 1):150382. doi: 10.1016/j.scitotenv.2021.150382. Epub 2021 Sep 17.
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 CaO particle formed layer by layer was prepared with an in-situ method and optimized to remove phosphorous and inhibit algae growth. The stable HO 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 through permanganate-based titration study. For solution with an initial phosphorous concentration of 10 mg·L, 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 CaO-functionalized bead inhibited algae growth with an effect lasting over 170 d, which was much better than liquid HO and Ca(OH) 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 CaO-functionalized material is promising for simultaneous removal of phosphorous and management of HABs.
同时去除磷（P）和藻类对于减轻富营养化非常重要，但在修复有害藻华（HAB）污染的水中却相当具有挑战性。本研究采用原位法制备了一种经 CaO 颗粒层层修饰的湿海藻酸钠珠，并对其进行了优化，以去除磷并抑制藻类生长。在 26 天的时间内，观察到稳定的 HO 释放，浓度水平为 0.06 mM。通过高锰酸盐滴定研究发现，最优珠中的过氧基团（-O-O-）含量为 0.44 mmol·g。对于初始磷浓度为 10 mg·L 的溶液，在 pH 3.0-10.0 范围内，去除率约为 97%。XRD、SEM 和 XPS 研究以及动力学模型表明，磷的去除主要归因于珠中形成的不溶性 Ca-P 化合物。与液体 HO 和 Ca(OH)珠相比，CaO 功能化珠对藻类生长的抑制作用可持续 170 天以上，效果更好；同时还能获得约 70%的磷去除效率。此外，该珠在实际水库水源水中的除藻效果良好。综上所述，本研究表明，CaO 功能化材料有望用于同时去除磷和管理 HAB。
