In this study, the efficiency of electrocoagulation (EC) with iron electrodes was applied to remove two phosphonates, 1-hydroxyethylidene-1, 1-diphosphonic acid (HEDP) and nitrilotris(methylene) triphosphonic acid (NTMP) from concentrates. This work provides a detailed description of the experimental procedure and results on phosphonate removal and recovery from different electrolytes, including synthetic and real reverse osmosis (RO) membrane concentrates. This research showed high selectivity of EC, removing 100% and 80% of the NTMP and the HEDP respectively, confirming no competition with sulfates, nitrates, or silica. When experimenting with other electrolytes, calcium showed to be critical in enhancing the flocculation process, while calcium carbonate precipitation contributed to capturing the phosphonates from the concentrate. The produced iron oxide (sludge) was confirmed as goethite and akaganéite, and finally transformed into hematite, indicating the oxidation from Fe²⁺ to Fe³⁺ during the EC process. After the iron precipitate collection, an alkaline wash of the sludge was enough to recover 100% of the initial phosphorus from the NTMP phosphonate. However, further research is needed to optimize the recovery procedure and to improve the results with the HEDP. 70 and 140 A·m^-2 current densities were optimal to bring HEDP and NTMP concentrations down to 32 μM (1 mg·L^-1) in only 30 and 10 minutes respectively. In these conditions, the operational costs, 1.10 and 0.03 €·m^-3 of treated concentrate, were estimated for HEDP and NTMP respectively. Even when EC has been widely studied for phosphate removal, this technique has been barely applied to treat concentrates containing phosphonate-based antiscalants. EC opens new possibilities for phosphonates and phosphorus to be removed and recovered respectively from membrane and other concentrates.

在这项研究中，铁电极电凝 (EC) 的效率被应用于从浓缩物中去除两种膦酸盐，1-hydroxyethylidene-1, 1-diphosphonic acid (HEDP) 和 nitrilotris(methylene) triphosphonic acid (NTMP)。这项工作详细描述了从不同电解质中去除和回收膦酸盐的实验程序和结果，包括合成和真正的反渗透 (RO) 膜浓缩物。该研究表明 EC 具有高选择性，分别去除 100% 和 80% 的 NTMP 和 HEDP，证实不与硫酸盐、硝酸盐或二氧化硅竞争。当用其他电解质进行实验时，钙显示出对增强絮凝过程至关重要，而碳酸钙沉淀有助于从浓缩物中捕获膦酸盐。²⁺到 Fe ³⁺在 EC 过程中。收集铁沉淀物后，对污泥进行碱洗足以从 NTMP 膦酸盐中回收 100% 的初始磷。然而，需要进一步研究来优化恢复程序并改善 HEDP 的结果。70 和 140  A·m ^-2电流密度最适合分别在 30 分钟和 10分钟内将 HEDP 和 NTMP 浓度降至 32 μM (1  mg·L ^-1  ) 。在这些条件下，运营成本分别为 1.10 和 0.03 €·m ^-3经处理的精矿，分别估计 HEDP 和 NTMP。即使在 EC 已被广泛研究用于除磷时，该技术也几乎没有应用于处理含有膦酸盐基阻垢剂的浓缩物。EC 为分别从膜和其他浓缩物中去除和回收膦酸盐和磷开辟了新的可能性。