State Key Laboratory of Pollution Control and Resource Reuse, Shanghai Institute of Pollution Control and Ecological Security, Key Laboratory of Yangtze River Water Environment of Ministry of Education, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China; Tongji Advanced Membrane Technology Center, Shanghai 200092, China.
Tongji Architectural Design (Group) Co., Ltd., Shanghai 200092, China.
Water Res. 2024 Nov 15;266:122424. doi: 10.1016/j.watres.2024.122424. Epub 2024 Sep 12.
The economical and efficient removal of nickel nitrate from industrial wastewater remains a challenge. Herein, we developed an innovative electrochemical membrane filtration system that used a periodic polarity reversal process to adjust the acid-base environment near membrane interface for the recovery of nickel (II) and ammonia. The Ru based electrocatalytic layer could boost the selective reduction of nitrate to ammonia by generating atomic hydrogen, resulting in the precipitation of Ni by the increasing pH at the membrane interface. Then, the precipitation of Ni(OH) could be effectively stripped and collected under the periodic polarity reversal process. In-situ interfacial measurements demonstrated that the polarity reversal process enabled a reversible transformation between strongly acidic (pH < 2) and alkaline (pH > 13) environments within a 200 µm range at the membrane interface. In continuous flow operation treating real industrial wastewater containing 96.7 mg-N L nitrate and 135.0 mg L Ni, the system demonstrated the capability to achieve 92.5 ± 2.6 % nitrate removal (with a recovery efficiency of 15.1 ± 1.9 g-NH kWh) and 99.7 ± 0.1 % Ni²⁺ removal (with a recovery efficiency of 24.9 ± 2.4 g-Ni kWh). Additionally, the specific treatment cost was approximately $0.17 m, attributed to the recovery of Ni(OH)₂ and ammonia. Furthermore, this system could deliver a significant economic benefit ($1.64 per m) for treating a high concentration real wastewater (331.5 mg-N L nitrate and 1496.3 mg L Ni), outperforming traditional alkali precipitation and biological nitrification/denitrification processes. Overall, our study presents an economical and sustainable method for recovering valuable chemicals from wastewater containing heavy metals and inorganic nitrogen, potentially advancing cost-effective water treatment technologies.
从工业废水中经济高效地去除硝酸镍仍然是一个挑战。在此，我们开发了一种创新的电化学膜过滤系统，该系统使用周期性极性反转过程来调节膜界面附近的酸碱环境，以回收镍（II）和氨。基于 Ru 的电催化层可以通过生成原子氢来促进硝酸盐选择性还原为氨，从而在膜界面增加 pH 值导致镍沉淀。然后，在周期性极性反转过程中可以有效地将 Ni(OH)₂沉淀剥落并收集。原位界面测量表明，极性反转过程可以在膜界面 200 µm 范围内实现强酸性（pH < 2）和碱性（pH > 13）环境之间的可逆转化。在连续流动操作中，处理含有 96.7 mg-N L 硝酸盐和 135.0 mg L Ni 的实际工业废水时，该系统能够实现 92.5 ± 2.6 %的硝酸盐去除（回收效率为 15.1 ± 1.9 g-NH kWh）和 99.7 ± 0.1 %的 Ni²⁺去除（回收效率为 24.9 ± 2.4 g-Ni kWh）。此外，特定的处理成本约为$0.17 m，归因于 Ni(OH)₂和氨的回收。此外，该系统可以为处理高浓度实际废水（331.5 mg-N L 硝酸盐和 1496.3 mg L Ni）带来显著的经济效益（每立方米$1.64），优于传统的碱沉淀和生物硝化/反硝化工艺。总的来说，我们的研究为从含有重金属和无机氮的废水中回收有价值的化学品提供了一种经济且可持续的方法，可能会推动具有成本效益的水处理技术的发展。
