State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, No.73 Huanghe Road, Nangang District, Harbin 150090, China.
School of Environmental Science and Engineering, Tianjin University, No. 92 Weijin Road, Nankai District, Tianjin 300072, China.
Water Res. 2018 Jul 1;138:129-136. doi: 10.1016/j.watres.2018.03.037. Epub 2018 Mar 16.
A migration electric-field assisted electrocoagulation (MEAEC) system was developed to increase phosphate removal from domestic wastewater, with reduced energy consumption, using a titanium charging (inert) electrode and a sacrificial iron anode. In the MEAEC, an electric field was applied between the inert electrode (titanium) and an air cathode to drive migration of phosphate anions towards the sacrificial anode. Current was then applied between the sacrificial anode (Fe or Al mesh) and the air cathode to drive electrocoagulation of phosphate. A MEAEC with the Fe electrode using primary clarifier effluent achieved 98% phosphate removal, producing water with a total phosphorus of 0.3 mg/L with <6 min total treatment time (five cycles; each 10 s inert electrode charging, and 1 min electrocoagulation), at a constant current density of 1 mA/cm. In the absence of the 10 s charging time, electrocoagulation required 15 min for the same removal. With an aluminum anode and the same phosphorus removal, the MEAEC required 7 cycles (7 min total treatment, 1 min 10 s total charging), while conventional electrocoagulation required 20 min. The energy demand of Fe-MEAEC was only 0.039 kWh/m for 98% phosphate removal, which was 35% less than with the Al-MEAEC of 0.06 kWh/m, and 28% less than that previously obtained using an inert graphite electrode. Analysis of the precipitate showed that a less porous precipitate was obtained with the Al anode than with the Fe anode. The phosphorus in precipitate of Fe-MEAEC was identified as PO and HPO, while the Fe was present as both Fe and Fe. Only HPO and Al were identified in the precipitate of the Al-MEAEC. These results indicated that the MEAEC with a titanium inert charging electrode and iron anode could achieve the most efficient phosphate removal with very low energy demands, compared to previous electrochemical approaches.
开发了一种迁移电场辅助电凝（MEAEC）系统，以使用钛充电（惰性）电极和牺牲铁阳极降低能耗，从生活废水中去除磷酸盐。在 MEAEC 中，在惰性电极（钛）和空气阴极之间施加电场，以驱动磷酸盐阴离子向牺牲阳极迁移。然后，在牺牲阳极（Fe 或 Al 网）和空气阴极之间施加电流，以驱动磷酸盐的电凝。使用初沉池出水的 MEAEC 与 Fe 电极实现了 98%的磷酸盐去除，总磷为 0.3mg/L，总处理时间<6min（五个循环；每个 10s 惰性电极充电，1min 电凝），电流密度为 1mA/cm。在没有 10s 充电时间的情况下，相同的去除需要 15min 进行电凝。使用铝阳极和相同的磷去除率，MEAEC 需要 7 个循环（7min 总处理时间，1min 10s 总充电时间），而传统电凝需要 20min。Fe-MEAEC 的能量需求仅为 0.039kWh/m 即可去除 98%的磷酸盐，比 Al-MEAEC 的 0.06kWh/m 低 35%，比以前使用惰性石墨电极获得的能量低 28%。对沉淀物的分析表明，与 Fe 阳极相比，Al 阳极得到的沉淀物孔隙率更低。Fe-MEAEC 沉淀物中的磷被鉴定为 PO 和 HPO，而 Fe 则同时以 Fe 和 Fe 的形式存在。在 Al-MEAEC 的沉淀物中仅鉴定出 HPO 和 Al。这些结果表明，与以前的电化学方法相比，使用钛惰性充电电极和铁阳极的 MEAEC 可以以非常低的能耗实现最有效的磷酸盐去除。
