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 Wen's Research Group​

Wen Zhang, Ph.D., P.E., BCEE

Principal Investigator

Phone: (973) 596-5520 
Fax: (973) 596-5790
Email: wen.zhang@njit.edu

Office Location: Colton Hall 211

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Electrocatalytic Upcycling of Nitrate Wastewater to Ammonia Fertilizer via Electrified Membrane 

Dr. Wen Zhang’s group in New Jersey Institute of Technology reported an electrified membrane process demonstrated for the first time to achieve NO3− removal/upcycling as nitrogen fertilizer with reduced energy and chemical consumption as opposed to the conventional biological nitrogen removal processes (e.g., nitrification and denitrification). Specifically, this study presents an electrified membrane made of a CuO@Cu foam and a polytetrafluoroethylene (PTFE) hydrophobic substrate for reducing NO3− to NH3 and upcycling NH3 into (NH4)2SO4, a liquid fertilizer readily for use. A paired electrolysis process without the external acid/base consumption was achieved under a partial current density of 63.8±4.4 mA·cm−2 on the cathodic membrane, which removed 99.9% NO3− in the feed (150 mM NO3−) after 5 h operation with a NH3 recovery rate of 99.5%. A recovery rate and energy consumption of 3100±91 g-(NH4)2SO4·m−2·d−1 and 21.8±3.8 kWh·kg−1-(NH4)2SO4 almost outcompetes the industrial ammonia production cost in the Haber-Bosch process. Density functional theory (DFT) calculations unraveled that the in situ electrochemical conversion of Cu2+ into Cu1+ provides high dynamic active species for NO3− reduction to NH3. This electrified membrane process was demonstrated to achieve synergistic nitrate decontamination and nutrient recovery with durable catalytic activity and stability. This study is supported by the NSF PFI-TT project and the INTERN program (Award number: 2016472) and Natural Science Foundation of Shandong Province (Award number: ZR2021MB003, ZR2021QB205).

新泽西理工大学土木与环境工程系张文教授课题组近期于Environmental Science & Technology发表研究论文, 报道了利用一个新型电气化膜工艺,与传统的生物脱氮过程(如硝化和反硝化)相比,该工艺首次实现了NO3-的去除和氮肥的生产,并无需输入酸碱等危险化学品。具体来说,本研究提出了一种由CuO@Cu泡沫和聚四氟乙烯(PTFE)疏水基材制成的电化膜,可将NO3-还原成NH3,并将NH3升级为(NH4)2SO4(一种常见的液体氮肥)。该阴极膜耦合了电子转移和相转移,生产NH3的部分电流密度达到了63.8±4.4 mA∙cm-2。通过耦合阴阳极的配对电解法,利用阴极和阳极界面的强碱性和强酸性环境,实现了NH4+到NH3的相转移过程和随后的NH3酸化固定为(NH4)2SO4的过程,从而避免了酸碱危险化学品的输入。该电化学反应器运行5小时后,可在150 mM NO3-进水条件去除99.9%的NO3-,并获得99.5%的NH3回收率,3100±91 g-(NH4)2SO4∙m-2∙d-1的硫酸铵生产速率和21.8±3.8 kWh∙kg-1-(NH4)2SO4的能耗。该能耗表现可与目前主流氨生产Haber-Bosch工艺的成本相当。密度泛函理论(DFT)计算表明,CuO阴极中的Cu2+可被原为电还原化学为Cu1+,为NO3-还原为NH3提供了高动态活性物种。这种电气化膜工艺被证明可以实现协同的硝酸盐净化和营养物回收,并具有持久的催化活性和稳定性(>40小时)。

Mr. Jianan Gao is a Ph.D. candidate in Environmental Engineering at NJIT. He received his B.S. in 2017 and M.S. in 2020 from Qingdao University of Technology. Mr. Gao’s research focuses on 1) rational surface/interface design and synthesis of functional materials for electrocatalytic wastewater treatment applications; 2) electrified reactive membrane flow-cell, assessment of water purification, resources recovery, disinfection performance, membrane fouling, and surface reactivity behavior.