Removal and recovery of phosphate from wastewater can minimize deleterious environmental impacts and supplement fertilizer supply. Hybrid anion exchangers (HAIX, with doped ferric oxide nanoparticles (FeOnp)) can remove phosphate from complex wastewaters and recover concentrated phosphate solutions. In this study, we integrate HAIX with a weak acid cation exchanger (WAC) to enrich phosphate and calcium in mild regenerants and precipitate both elements for recovery. We demonstrated an electro-assisted regeneration approach to avoid strong acid and base input. Based on demonstrated pH sensitivities of both materials, electrochemically produced mild electrolytes (pH 3 and pH 11), which are 100–1000 times less concentrated than typical regenerants, preserved 80% WAC and 50% HAIX capacities over five batch adsorption-regeneration cycles. FeOnp in HAIX facilitated regeneration due to pH sensitivity and their likely distribution on the resin particle surface, which reduced intraparticle diffusion path length. In column tests, repeatable phosphate removal (> 95%) from synthetic wastewater (3 mg P/L) was achieved with 20 kWh/kg P specific energy consumption. After removal, a similar 50% HAIX regeneration efficiency as batch experiments was achieved. In spent regenerant, more than 95% phosphorus was recovered as hydroxyapatite. This novel approach enhances ion exchange by minimizing chemical inputs.

从废水中去除和回收磷酸盐可将对环境的不利影响降至最低，并补充肥料。混合阴离子交换剂（HAIX，带有掺杂的三氧化二铁纳米粒子（FeOnp））可以从复杂废水中去除磷酸盐并回收浓缩的磷酸盐溶液。在这项研究中，我们将HAIX与弱酸性阳离子交换剂（WAC）集成在一起，以在温和的再生剂中富集磷酸盐和钙，并沉淀这两种元素以进行回收。我们展示了一种电辅助再生方法，可避免强酸和强碱输入。基于两种材料均显示出的pH敏感性，电化学生产的弱电解质（pH 3和pH 11）的浓度比典型再生剂低100-1000倍，在五个批次的吸附-再生循环中，其80％的WAC和50％的HAIX容量得以保留。由于pH敏感性及其在树脂颗粒表面的可能分布，HAIX中的FeOnp促进了再生，从而缩短了颗粒内扩散路径的长度。在柱测试中，以20 kWh / kg P的单位能耗实现了从合成废水（3 mg P / L）中可重复去除磷酸盐（> 95％）。去除后，达到了与分批实验相似的50％HAIX再生效率。在废再生剂中，超过95％的磷被回收为羟基磷灰石。这种新颖的方法通过最小化化学物质输入来增强离子交换。以20 kWh / kg P的单位能耗实现了来自合成废水（3 mg P / L）的95％。去除后，达到了与分批实验相似的50％HAIX再生效率。在废再生剂中，超过95％的磷被回收为羟基磷灰石。这种新颖的方法通过最小化化学物质输入来增强离子交换。以20 kWh / kg P的单位能耗实现了来自合成废水（3 mg P / L）的95％。去除后，达到了与间歇实验相似的50％HAIX再生效率。在废再生剂中，超过95％的磷被回收为羟基磷灰石。这种新颖的方法通过最小化化学物质输入来增强离子交换。