Wen Zhang, Ph.D., P.E., BCEE
Principal Investigator
Professor
Phone: (973) 596-5520
Fax: (973) 596-5790
Email: wen.zhang@njit.edu
Office Location: Colton Hall 211
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Dr. Zhang’s group published a paper in Nature Communications on resource recovery from wastewater using synchronous electrosynthesis and separation.
Source: https://www.nature.com/articles/s41467-024-52830-4
Under funding support from NSF and the NJIT’s Technology Innovation Translation and Acceleration (TITA) Seed Grant program, Dr. Zhang’s group has been working on the translational research and commercialization of electrochemical technologies that convert nitrate waste into useful ammonia products such as fertilizer and liquid ammonia. Recently, Dr. Jianan Gao from Professor Wen Zhang's team at New Jersey Institute of Technology published a research paper in Nature Communications titled "Direct electrosynthesis and separation of ammonia and chlorine from waste streams via a stacked membrane-free electrolyzer." This study integrates gas extraction electrodes into a flow-based membrane-free electrolyzer, achieving simultaneous electrosynthesis and separation of NH₃ and Cl₂ from waste streams, with high product purity, high yield, and minimal product loss.
Electrosynthesis, a viable path to decarbonize the chemical industry, has been harnessed to generate valuable chemicals under ambient conditions. Here, we present a membrane-free flow electrolyzer for paired electrocatalytic upcycling of nitrate (NO3−) and chloride (Cl−) to ammonia (NH3) and chlorine (Cl2) gases by utilizing waste streams as substitutes for traditional electrolytes. The electrolyzer concurrently couples electrosynthesis and gaseous-product separation, which minimizes the undesired redox reaction between NH3 and Cl2 and thus prevents products loss. Using a three-stacked-modules electrolyzer system, we efficiently processed a reverse osmosis retentate waste stream. This yielded high concentrations of (NH4)2SO4 (83.8 mM) and NaClO (243.4 mM) at an electrical cost of 7.1 kWh per kilogram of solid products, while residual NH3/NH4+ (0.3 mM), NO2− (0.2 mM), and Cl2/HClO/ClO− (0.1 mM) pollutants in the waste stream could meet the wastewater discharge regulations for nitrogen- and chlorine-species. This study underscores the value of pairing appropriate half-reactions, utilizing waste streams to replace traditional electrolytes, and merging product synthesis with separation to refine electrosynthesis platforms.
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