Unlike the case for inorganic phosphate (P_i), removing organic phosphorus (P_o) is more challenging. Conventional methods for removing P_o involve a two-step route, where P_o is first converted to P_i by an advanced oxidation process, followed by subsequent chemical precipitation/coagulation. Here, we propose a one-step CaO₂/UV method for simultaneous conversion and coprecipitation of phosphonates, a representative type of organic phosphorus compound. We discovered that the total P removal (82.0%) is much higher than the conversion efficiency of P_o to P_i (26.7%) under a dose of 1.5 mM CaO₂ and 4 h UV irradiation for nitrilotris-methylene phosphonic acid (NTMP) treatment, providing new directions for treating P_o compounds without completely breaking down the molecular structure. We further found that a CaO₂/P_o molar ratio of 1.5 is ideal for inducing the partial breakdown of the NTMP structure, Ca-phosphate formation, and coprecipitation of NTMP and its degradation intermediates. Beyond that, we noted that the presence of Ca²⁺ enhances the reactivity of NTMP with hydroxyl radicals, as supported by the improved conversion efficiency of P_o to P_i, i.e., 37.4% vs 9.1% under pH_i 11. We also demonstrated the preliminary feasibility of the CaO₂/UV system in treating the reverse osmosis concentrate. Our study offers a robust one-step approach and sheds new insights on the synergistic role of partial oxidation, complexation, and coprecipitation in dealing with phosphonate-laden wastewater.

中文翻译：

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CaO2/UV 有效处理含磷酸盐废水：部分氧化、络合和共沉淀

_{与无机磷酸盐 (P i} )的情况不同，去除有机磷 (P _o ) 更具挑战性。去除 P _o的传统方法涉及两步路线，其中 P _o首先通过高级氧化过程转化为 P _i，然后进行化学沉淀/凝结。在这里，我们提出了一种一步CaO ₂ /UV方法，用于同时转化和共沉淀膦酸盐（有机磷化合物的代表类型）。我们发现，在 1.5 mM CaO ₂剂量和 4 h 紫外线照射下，次氮基三亚甲基膦酸 (NTMP)的总 P 去除率 (82.0%) 远高于 P _o到 P _i的转化效率 (26.7%)。处理，为在不完全破坏分子结构的情况下处理P _o化合物提供了新的方向。我们进一步发现CaO ₂ /P _o摩尔比为1.5对于诱导NTMP结构的部分分解、磷酸钙的形成以及NTMP及其降解中间体的共沉淀是理想的。除此之外，我们注意到 Ca ²⁺的存在增强了 NTMP 与羟基自由基的反应性，这得到了 P _o到 P _i转化效率提高的支持，即在 pH _i 11下，分别为 37.4% 和 9.1%。我们还证明了CaO ₂ /UV系统处理反渗透浓缩液的初步可行性。我们的研究提供了一种稳健的一步法，并对部分氧化、络合和共沉淀在处理含膦酸盐废水中的协同作用提供了新的见解。