Division of Land and Water Resources Engineering, KTH Royal Institute of Technology, Teknikringen 76, SE-100 44 Stockholm, Sweden.
Division of Land and Water Resources Engineering, KTH Royal Institute of Technology, Teknikringen 76, SE-100 44 Stockholm, Sweden; Department of Soil and Environment, Swedish University of Agricultural Sciences, Box 7014, SE-750 07 Uppsala, Sweden.
Water Res. 2015 Dec 15;87:271-81. doi: 10.1016/j.watres.2015.09.035. Epub 2015 Sep 25.
Argon oxygen decarburisation (AOD) slag may be used for phosphorus (P) removal, as its high pH and weatherable calcium (Ca) minerals provide sufficient Ca(2+) and OH(-) for calcium phosphate (Ca-PO4) precipitation. This study examined the P removal performance of AOD slag for use as wastewater treatment material. Batch experiments were carried out using both synthetic P solution and real wastewater, followed by chemical modelling and X-ray absorption near edge structure (XANES) spectroscopy. The influences of initial P concentration, slag dose and modification by polyethylene glycol (PEG), an effective agent for generation of porous materials, were investigated to determine the optimal conditions for P removal by AOD slag. It was found that virgin AOD slag removed 94.8% of P from a synthetic P solution in 4 h and 97.8% in 10 h. This high P removal was accompanied by a rapid increase in pH from 7.0 to 10.74. The maximum P removal capacity (PRC) from synthetic P solution ranged from 1.3 to 27.5 mg P g(-1). The optimal AOD dose for P removal from wastewater, determined in 8-h batch experiments, was 25 g L(-1). PEG modification increased the reaction rate and resulted in higher final pH, increasing PRC by 47.9%. Combined Visual MINTEQ and XANES analysis for detailed examination of P removal mechanisms revealed that the main P removal mechanism was precipitation of calcium phosphate. According to the XANES analysis, the main Ca-PO4 precipitate formed on virgin AOD slag under low initial P concentration and high pH was apatite, while brushite was the dominant product at high initial P concentration and low pH.
氩氧脱碳（AOD）渣可用于除磷，因为其高 pH 值和风化钙（Ca）矿物提供了足够的 Ca(2+) 和 OH(-) 用于磷酸钙（Ca-PO4）沉淀。本研究考察了 AOD 渣作为废水处理材料的除磷性能。采用合成磷溶液和实际废水进行了批量实验，随后进行了化学建模和 X 射线吸收近边结构（XANES）光谱分析。考察了初始磷浓度、渣剂量以及通过聚乙二醇（PEG）改性（一种有效生成多孔材料的试剂）的影响，以确定 AOD 渣去除磷的最佳条件。结果表明，原始 AOD 渣在 4 小时内从合成磷溶液中去除了 94.8%的磷，在 10 小时内去除了 97.8%。这种高磷去除伴随着 pH 值从 7.0 快速增加到 10.74。从合成磷溶液中获得的最大磷去除容量（PRC）范围为 1.3 至 27.5mg P g(-1)。在 8 小时批量实验中确定的去除废水中磷的最佳 AOD 剂量为 25g L(-1)。PEG 改性提高了反应速率，导致最终 pH 值升高，PRC 增加了 47.9%。结合 Visual MINTEQ 和 XANES 分析对除磷机制的详细考察表明，主要的除磷机制是磷酸钙的沉淀。根据 XANES 分析，在低初始磷浓度和高 pH 值下，原始 AOD 渣上形成的主要磷去除产物是磷灰石，而在高初始磷浓度和低 pH 值下，主要产物是鸟粪石。
