Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong, China.
Water Supplies Department, Hong Kong Special Administrative Region, China.
Sci Total Environ. 2021 Oct 15;791:148281. doi: 10.1016/j.scitotenv.2021.148281. Epub 2021 Jun 5.
The use of magnetic lanthanum-based materials for phosphate removal from river water has gained increasing attention. However, challenges to produce and use lanthanum-based materials in large-scale or pilot-scale studies remain. In this work, a kilogram-scale FeO/La(OH) magnetically recyclable composite for removing phosphate from river water was developed through a low-temperature precipitation route. The composite was used to remove phosphate from river water at both bench- and pilot-scales. Based on the bench-scale tests, the developed FeO/La(OH) composite was found to have excellent magnetic particle separation efficiency (>98%) and a sorption capacity of 11.77 mg/g for phosphate. A 1.0 g/L dosage of the composite in the river water sample was able to selectively reduce the phosphate level from 0.089 to 0.005 mg/L in 60 min over five consecutive adsorption cycles. At the pilot-scale, the FeO/La(OH) composite only achieved 36.0% phosphate removal efficiency, which is considerably different from the bench-scale results over an operational time of five months and a total treatment volume of 300 m. This significantly reduced removal efficiency is mainly attributable to turbidity, suspended solids, and organic matter in the river water and the deteriorated magnetic separation efficiency. This study revealed potential challenges and shed new insights on moving magnetic nanocomposite-based technology from the bench-scale to the pilot-scale, which can inspire new designs for the application of similar technology.
从河水中去除磷酸盐的镧基磁性材料的应用越来越受到关注。然而，在大规模或中试规模研究中生产和使用镧基材料仍然存在挑战。在这项工作中，通过低温沉淀法开发了一种用于从河水中去除磷酸盐的公斤级 FeO/La(OH)可磁回收复合材料。该复合材料在中试和台架规模上用于从河水中去除磷酸盐。基于台架试验，所开发的 FeO/La(OH)复合材料具有出色的磁性颗粒分离效率（>98%）和 11.77 mg/g 的磷酸盐吸附容量。在河水中，以 1.0 g/L 的复合材料剂量，在五个连续吸附循环中，在 60 分钟内可将磷酸盐水平从 0.089 降至 0.005 mg/L。在中试规模下，FeO/La(OH)复合材料仅实现了 36.0%的磷酸盐去除效率，与五个月的运行时间和 300 m 的总处理量相比，这与台架结果有很大的不同。这种去除效率的显著降低主要归因于河水的浊度、悬浮物和有机物以及磁分离效率的恶化。本研究揭示了将基于磁性纳米复合材料的技术从台架规模转移到中试规模的潜在挑战和新见解，这可为类似技术的应用提供新的设计思路。
