ABSTRACT

Electric arc furnace (EAF) slag aggregate, a waste by-product of the steel industry, exhibited a high potential for phosphorus (P) removal and had attracted considerable attention. The main objectives of this study were to evaluate the performance of using EAF slag aggregate as an adsorbent for P removal and identify its P removal capacity. A series of batch tests showed that P removal capacity of EAF slag increases gradually with the increase of pH with a range of 2–10, while the highest P removal capacity (1.94 mg/g) can be obtained at pH 12. The adsorption kinetics of P on EAF slag can be described by pseudo-second-order kinetic equations. Isothermal adsorption simulations showed that the best fitted model was the Freundlich model with a correlation coefficient of 0.9825. A continuous flow column experiment feeding a synthetic influent containing 15 mg P/L was operated for 60 days and the P removal efficiency was greater than 95% with a P removal capacity of 1.6 mg P/g slag. The results obtained in this study showed that EAF slag could act as an efficient adsorbent for P removal. Calcium phosphate precipitation depends on the release of Ca²⁺ and OH⁻ by the dissolution of calcium oxide in EAF slag was found to be the dominant removal mechanism for P removal.

摘要

电弧炉 (EAF) 渣骨料是钢铁工业的副产品，具有很高的除磷 (P) 潜力，引起了广泛关注。本研究的主要目的是评估使用 EAF 炉渣骨料作为除磷吸附剂的性能并确定其除磷能力。一系列批次试验表明，随着 pH 值的增加，电炉渣的除磷能力逐渐增加，范围为 2-10，而在 pH 12 时可获得最高的除磷能力（1.94 mg/g）。吸附动力学电炉渣中 P 的含量可以用准二级动力学方程来描述。等温吸附模拟表明，最佳拟合模型是 Freundlich 模型，相关系数为 0.9825。连续流柱实验进料含 15 mg P/L 的合成进水，运行 60 天，P 去除率大于 95%，P 去除能力为 1.6 mg P/g 渣。本研究获得的结果表明，电弧炉渣可以作为一种有效的除磷吸附剂。磷酸钙沉淀取决于Ca的释放^{发现通过氧化钙溶解在电弧炉炉渣中的2+}和 OH ^-是去除 P 的主要去除机制。