Explore the Nano World
Wen's Research Group
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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1. Electrochemically Reactive Membranes for Efficient Biomass Recovery and Pollutant Degradation
This research embodies sustainability principles and approaches to remove and recovery nitrogen from nitrate-containing wastewater that is also increasingly being considered as a potential nitrogen resource rather than as a waste.3 The synergies of combining NO3− removal and upcycling into commodity products such as ammonia fertilizer have been reported in literature. However, recycling of this resource for fertilization will require innovation, analysis, ingenuity and significant changes in water and wastewater management. To enable the nitrate nitrogen upcycling, my research reported a novel three-phase interface design to achieve NO3− removal, ammonia production, and NH3 recovery from wastewaters simultaneously, where electron-transfer reactions were coupled with the phase-transfer reaction. In this system, the cathode equipped on the interface was certainly the core component, the following points should be therefore taken into consideration for cathode preparation: (i) abundant reactive sites with strong activity towards NO3− reduction, (ii) high selectivity towards ammonia, and (iii) strongly basic local pH near the cathode surface created by HER and NO3− reduction reaction to maintain the generation of gaseous NH3. Thus, in present system, boosting the active sites towards electrocatalytic NO3− reduction to ammonia as well as HER and balancing the active site distribution for the above two reactions were both essential for simultaneous ammonia electrosynthesis and NH3 separation. The H atom adsorption strength of cobalt-based catalysts could be modulated via electronic construction engineering, leading to elaborately controlled production of strong reducing agent (∙H) or HER intermediate.
Major achievements:
(1) One Ph.D. student (Likun Hua) is currently engaged and trained by this project;
(2) One journal articles published in Bioresource Technology;
(3) One provisional patent disclosure was filed at NJIT;
(4) Two NSF grants (one CBET and one national NSF I-Corps; $210,000 in total from 2015 to 2018);
(5) One NSF I-Corps Site grant;
(6) One NSF INTERN grant ($31,000)
(7) First Place Award in 2018 Student Research Poster Competition of AWWA NJ 83rd Annual Conference
(8) ENVR Graduate Award from Division of Environmental Chemistry of ACS;
(9) URI phase I and II grants;
(10) 3 undergraduate and 2 master students were involved and trained;
(11) One undergraduate student (Marah Magpile) received the ACS Division of Environmental Chemistry 2016 Undergraduate Award; and the other two (Andrea Cano and Maira Valenci) received the 2016 TechQuest First Place Award.
Micropollution in natural waters such as rivers and groundwater aquifers is a widespread problem that prevents these potentially potable sources from being used as drinking water. At the same time, utilization of biomass-based raw materials (e.g., bacteria, algae, and cellulose) for the production of high value chemicals such as proteins, pharmaceuticals, and biofuels is gaining an increasing interest. Traditional membrane filtration faces major challenges such as polymer aging, membrane fouling, and high costs. Thus, developing sustainable and efficient membrane filtration technologies is not only critical for safe drinking water supply but also important for many chemical processing or refineries such as biomass separation and biofuel production. This project is to develop an innovative and multifunctional reactive electrochemical membrane (REM) that exhibit great antifouling characteristics and strong surface reactivity. Our research focuses on four aspects: (1) development and testing of a suite of tailored monolithic or nanofibrous REMs in biomass recovery; (2) evaluation of biomass separation efficiency, permeate water treatment, and anti-fouling properties using algae as model organisms; (3) experimental and modeling assessment of membrane fouling and regeneration kinetics and mechanisms; and (4) Ti4O7 reactive electrochemical membrane filtration for recalcitrant pollutants removal and microbial disinfection. The results not only provided fundamental guidelines as to the rational design of REMs with controlled and efficient performance, flexible structure, and durability of operation for algal recovery, but also leads to an avenue for the development of a new generation of reactive membranes that can be applied in other disciplines in addition to algal separation (e.g., food processing, drinking water treatment, and biomolecule purification in pharmaceutical industries).
2. Electrochemically Reactive Membranes for Efficient Biomass Recovery and Pollutant Degradation