Despite centuries of advancements in water treatment, hundreds of millions of people worldwide continue to suffer detrimental health impacts from drinking water with unsafe fluoride levels. Our study compares the performance of low-cost mildly heated bauxite ores and commercial activated alumina (AA) in treating a synthetic groundwater matrix representative of global, fluoride-contaminated aquifers. Batch kinetics studies of fluoride adsorption onto global bauxite ores and AA follow a pseudo-second order rate law, with adsorption increasing exponentially in the first few hours. Fluoride removal efficiencies increase from 73.5% to 85.5% as media particle sizes decrease from 0.6–1.2 mm to <0.1 mm. Column studies demonstrate that increasing the ratio of reactive media in filters from 1 to 100 weight percent increases the volume of treated water from 0.2–56.1 L for Guinea bauxite (GB) and from 0.5–58.3 L for AA. We predict the performance of large-scale columns by modifying the bed depth service time (BDST) model to scale breakthrough time with adsorbent mass rather than with column height. Our modified BDST model predicts that large-scale columns using 1039 kg AA and 1436 kg GB can treat 405 444 L and 338 859 L of potable water in 1.4 and 1.1 months. We also demonstrate application of the rapid small scale column test (RSSCT) model to design smaller lab-scale columns with lower resource, cost, and time inputs by scaling down known field systems parameters including column height, pump flow rate, empty bed contact time, and approach velocity.

中文翻译：

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使用粒状铝土矿过滤介质作为活性氧化铝的经济且可持续的替代品有效去除氟化物

尽管在水处理方面取得了几个世纪的进步，但全世界仍有数亿人因饮用含氟量不安全的水而继续遭受有害的健康影响。我们的研究比较了低成本温和加热铝土矿和商业活性氧化铝 (AA) 在处理代表全球氟化物污染含水层的合成地下水基质方面的性能。氟化物吸附在全球铝土矿和 AA 上的批量动力学研究遵循伪二级速率定律，吸附在最初几个小时内呈指数增长。随着介质粒径从 0.6-1.2 毫米减小到 <0.1 毫米，氟化物去除效率从 73.5% 增加到 85.5%。色谱柱研究表明，将过滤器中反应介质的比例从 1 重量% 增加到 100 重量%，几内亚铝土矿 (GB) 的处理水体积从 0.2-56.1 L 增加，AA 的处理水体积从 0.5-58.3 L 增加。我们通过修改床深度服务时间 (BDST) 模型来预测大型色谱柱的性能，以使用吸附剂质量而不是色谱柱高度来衡量突破时间。我们改进的 BDST 模型预测，使用 1039 kg AA 和 1436 kg GB 的大型色谱柱可以在 1.4 和 1.1 个月内处理 405 444 L 和 338 859 L 的饮用水。我们还展示了快速小规模柱测试 (RSSCT) 模型的应用，通过缩小已知的现场系统参数（包括柱高、泵流速、空床接触时间）来设计具有较低资源、成本和时间投入的较小实验室规模的柱，和接近速度。