Wen's Research Group

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  • Doctoral student, Jiahe Zhang, Delivered Two Oral Presentations at ACS Spring 2025 Conference in San Diego, California

    Jiahe Zhang, a Ph.D. student in Environmental Engineering at the New Jersey Institute of Technology (NJIT), delivered two oral presentations at the 2025 American Chemical Society (ACS) Spring Conference in San Diego on March 24-28 2025.

    For the first oral presentation, Jiahe Zhang presented our results related to the mechanisms and performance of PFAS removal using commercial reverse osmosis (RO) and nanofiltration (NF) membranes under complex water chemistries. This work was conducted in collaboration with Dr. Qingquan Ma and Guangyu Zhu, under the supervision of Professor Wen Zhang under the funding support from the NSF Industry/University Cooperative Research Center for Membrane Science, Engineering and Technology. This talk systematically evaluated the effects of key operational factors—including pressure, temperature, pH, and water matrix components such as DOM and surfactants—on the rejection behaviors of short- and long-chain PFAS. By integrating surface and structural analyses such as SEM, AFM-IR, and KPFM, Jiahe provided new insights into how membrane surface properties and compaction affect PFAS transport and electrostatic exclusion. This work contributes to a deeper understanding of physicochemical interactions at the membrane interface and offers promising directions for optimizing membrane-based treatment of emerging contaminants like PFAS in wastewater systems.

    The second oral presentation, titled “Ammonia Recovery from Wastewater Containing Nitrate and Ammonia Using an Integrated Electrochemical Membrane Flow Reactor,”

    showcased an innovative approach to simultaneously converting nitrate pollutants into valuable ammonia and recovering existing ammonium from wastewater. His reactor integrates selective electrocatalysis with real-time ammonia separation to enhance nitrogen circularity in municipal and agricultural waste streams. A key innovation lies in the use of hydrophobic catalyst interfaces and advanced membrane configurations to finely regulate gas-liquid-solid interactions—overcoming traditional challenges in product desorption and gas bubble accumulation. With a U.S. patent application underway and a pilot-scale reactor developed, this work demonstrates the practical translation of electrochemical nitrogen removal technologies from laboratory research to real-world implementation, advancing the field of environmental sustainability. The study has been supported by the NSF/BSF project (award number: 2215387), New Jersey Water Resources Research Institute (award number: G21AP10595-01), and the 2024 NJIT’s Technology Innovation Translation and Acceleration (TITA) Seed Grant program.

    In summary, attending the 2025 ACS Spring Meeting was both academically enriching and personally rewarding. Through two oral presentations, Jiahe Zhang showcased his latest research on PFAS removal and ammonia recovery, highlighting innovations in membrane science and electrochemical engineering. The conference offered valuable opportunities to exchange ideas with experts across disciplines, gain feedback, and explore future collaborations. Complemented by the vibrant setting of San Diego, this experience not only advanced Jiahe’s research visibility but also deepened our social networking with the broader scientific community. Beyond the academic sessions, exploring the vibrant city of San Diego was equally enjoyable. With its sunny skies, coastal breeze, and iconic palm-lined streets, the city provided a refreshing backdrop for reflection and connection. From scenic waterfront walks to bustling local eateries, the experience added a memorable and relaxing dimension to the conference trip.

  • Researchers Unveil New Insights into Airborne PFAS Pollution in Northern New Jersey

    https://doi.org/10.1016/j.scitotenv.2025.179037

    A collaborative study led by environmental scientists from Rutgers University, NJIT, and the Meadowlands Research and Restoration Institute (MRRI) sheds light on the presence and behavior of airborne Per- and Polyfluoroalkyl Substances (PFAS) in Northern New Jersey’s urban atmosphere.

    Dr. Wen Zhang and his former Ph.D. student, Dr. Fangzhou Liu, alongside researchers (Cheryl Yao, Xinting Wang, Dr. Francisco J. Artigas and Dr. Gao Yuan) from multiple institutions, has co-authored a groundbreaking study investigating the distribution and partitioning of PFAS in the region’s air. The research, published in Science of the Total Environment, provides crucial data on the presence of these persistent and potentially harmful pollutants, which have been widely used in industrial applications and consumer products. PFAS are known for their resistance to degradation and have been linked to adverse health effects. While much research has focused on their presence in water and soil, this study highlights the importance of monitoring airborne PFAS, which can contribute to long-range transport and human inhalation exposure. The findings underscore the need for improved air quality monitoring and regulatory measures to address this emerging concern.

    This study exemplifies the power of interdisciplinary collaboration, combining expertise from environmental science, atmospheric chemistry, and engineering to enhance our understanding of PFAS pollution. The research team hopes their findings will inform policy decisions and inspire further studies on the environmental fate and human exposure risks associated with airborne PFAS.

    For more details, the full study can be accessed here.

  • Hydrothermal valorization of cellulose tuned by non-corrosive Lewis acids and bases

    https://doi.org/10.1016/j.cej.2025.161109

    Dr. Zhang’s former postdoc, Dr. Jiahui Hu, published a paper in Chemical Engineering Journal and elucidating the regulation mechanism of cellulose hydrothermal valorization via non-corrosive Lewis acids and bases. Cellulose, the most abundant component of biomass, is an essential renewable and carbon–neutral resource that can be converted into valuable products through hydrothermal treatment. However, the industrial application of hydrothermal technology for cellulose valorization is hindered by the formation of complex products which are challenging to separate. This study introduces a novel strategy for regulating product formation in cellulose hydrothermal conversion using non-corrosive Lewis acids and bases, integrating density functional theory calculations with experimental investigations. Frontier molecular orbital analysis reveals that peroxodisulfate, with strong electrophilicity, acts as a Lewis acid, directing the reaction toward the formation of levulinic acid. Conversely, peroxymonosulfate and thiourea, as nucleophilic Lewis bases, promote the accumulation of hydroxymethylfurfural by preventing its further degradation to levulinic acid and polymerization to carbon microspheres. Thiosulfate, with excessively strong nucleophilicity, inhibits the conversion of cellulose into sugars, thereby altering the whole hydrothermal decomposition pathways. Focusing on thiourea as a model additive, the study identified optimal conditions for hydroxymethylfurfural accumulation: a thiourea-to-cellulose ratio of 0.05:1, a reaction temperature of 220 °C, and a reaction time of 2 h. Additionally, increasing the initial reaction pressure from 0.1 MPa to 1.5 MPa resulted in a 92 % increase in hydroxymethylfurfural yield. This study provides a theoretical foundation for regulating cellulose hydrothermal processing via Lewis acids and bases, offering new insights into selective product formation and advancing biomass valorization technologies.

  • NJIT Researchers Advance Air Gap Membrane Distillation with High Thermal Efficiency

    Dr. Wen Zhang and Dr. Kamalesh K. Sirkar, along with their research team (e.g., Fangzhou Liu, Dr. Weihua Qing, Dr. John Chau, Dr. Qingquan Ma, and Guangyu Zhu) at the New Jersey Institute of Technology (NJIT), have published a groundbreaking study in Desalination on an innovative air gap membrane distillation (AGMD) module that significantly enhances water treatment performance.

    The study introduces a novel two-hollow-fiber-set membrane module, where a poly(etheretherketone) (PEEK) hollow fiber membrane (HFM) is placed inside a hydrophobic polyvinylidene fluoride (PVDF) HFM, creating an ultra-thin air gap of just 121 μm. This design achieves high thermal efficiency and improved water vapor flux, reaching 9.05 kg/m²∙h under optimal conditions (85°C brine, 5°C coolant).

    Key contributions of the study include:
    ✅ High packing density of 1297 m²/m³, enabling efficient mass transfer
    ✅ 98.7% salt rejection, ensuring desalination effectiveness
    ✅ Finite element analysis using COMSOL Multiphysics to predict water flux and temperature profiles
    ✅ Principal component analysis (PCA) to assess performance factors, highlighting the critical role of air gap thickness in temperature polarization

    This innovative approach could lead to more efficient and scalable membrane distillation systems for water purification, desalination, and resource recovery.

    📖 Read the full paper: https://doi.org/10.1016/j.desal.2025.118683

    🔬 #MembraneDistillation #WaterTreatment #Nanotechnology #NJIT #SustainableEngineering

  • 2025 spring farewell and welcome party for visiting scholars

    http://www.wenresearch.com/visiting-scholars.html

    On 01/26/2025, we held a family party at Professor Zhang’s home to say goodbye to our three group members, Dr. Ge, Hongmei, Dr. Jiahui Hu and Lili Li.

    Dr. Ge is a lecturer at Hubei University of Technology and her research areas include emerging contaminants removal by microalgae, and microalgal removal and harvesting.  She has been here with Dr. Zhang’s group as a visiting scholar from 02/2024 to 02/2025.

    Dr. Jiahui Hu is a postdoctoral researcher who joined Zhang’s group in February 2025 and conducts research on microplastics/PFAS detection in food waste and membrane distillation. After leaving Zhang’s group this spring, she will begin a postdoctoral position at the U.S. Salinity Laboratory (USDA-ARS) in Riverside, California, focusing on PFAS in agricultural systems.

    Lili Li is a doctoral student from the Institute of Hydrobiology, Chinese Academy of Sciences, and has been conducting research in algae-laden water separation technologies and their engineering application. She stayed in Zhang’s group as a visiting student from 02/2023 to 02/2025 and conducted research in magnetic separation of algae and CO2 nanobubbles for enhanced algal growth.

    A heart-felt wishes to these scholars for their prosperous future and careers!

    Meanwhile, we recently accepted three new visiting scholars this spring:

    Dr. Mu Hui, professor from Jinan University, will start her visiting scholarship in Zhang’s group for one year and will focus on resource recovery for environmental applications.

    Dr. Mubarshar Mubashar is a postdoctoral fellow at the Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China. His research focuses on mixotrophy-based nutrient recovery from wastewater, carbon neutrality, and carbon capture and utilization using microalgae. Mubashar will stay in Zhang’s group as a visiting scholar, where he will conduct research in CO2 nanobubble-driven mixotrophy-based carbon capture and nutrient recovery.

    Haodong Jia, a Ph.D. student from Shanxi University, will work on PMS activation for wastewater treatment, electrochemistry analysis of catalysts, and membrane distillation for desalination and pollution removal. His visiting scholar will start from January to June 2025.

  • Deciphering the Mechanisms of Nanobubble Production in Membrane Technology for Enhanced Oxygenation and Efficiency

    Dr. Shan Xue, a former Ph.D. student and postdoc of Prof. Zhang’s group, now a research scientist at PureNanoTech Inc., recently published her postdoctoral research in Langmuir (https://doi.org/10.1021/acs.langmuir.4c04781), which evaluated the interfacial processes of nanobubble evolution and production across a porous membrane surface. Many operational factors and membrane properties can significantly influence nanobubble production and characteristics. This study examined how membrane pore size, surface hydrophobicity, and gas/water flow conditions affect nanobubble size and concentration. Findings reveal that reducing the ceramic membrane pore size from 200 nm to 10 nm slightly decreased the mean nanobubble diameter, from 115 nm to 89 nm. Furthermore, membranes with a hydrophilic outer surface and hydrophobic pore surface generated smaller nanobubbles with higher concentrations in water. Additionally, a high water cross-flow rate (e.g., >1 L·min⁻¹) increased the nanobubble concentration, though bubble size remained unaffected. In contrast, the gas flow rate had a more pronounced effect. Increasing the gas flow rate from 0.5 to 12 L·min⁻¹ significantly raised the nanobubble concentration from 3.09 × 10⁸ to 1.24 × 10⁹ bubbles·mL⁻¹ while reducing the mean bubble diameter from 100 nm to 79 nm. An interfacial force model was applied to analyze bubble detachment at the membrane pore outlet, considering factors such as gas flow/pressure, surface tension, and shear forces from water flow. These findings offer valuable insights into the mechanisms governing nanobubble generation via gas injection through porous membranes.

  • NJIT Hosts Successful Workshop on Nanobubbles for Sustainability

    On January 24, 2025, the New Jersey Institute of Technology (NJIT) hosted the workshop “Nanobubbles for Sustainability: Transforming Agriculture and Environmental Management” at the Weston Hall 220 Gallery Conference Room. Organized by Dr. Wen Zhang, the event brought together leading researchers, industry professionals, students, and policymakers from across the globe to explore the transformative applications of nanobubble technology in sustainable agriculture and environmental management.

    The workshop highlighted nanobubbles’ potential in areas such as pollution mitigation, soil health improvement, water efficiency, and agricultural productivity. Discussions also delved into innovative strategies for pollutant degradation, carbon sequestration, and improving water use in controlled environment agriculture. Attendees gained valuable insights into the science behind nanobubbles and their practical applications in addressing pressing global challenges.

    The event featured an impressive lineup of speakers, including international experts such as Prof. Pan Li (Tongji University), Prof. Yoshikatsu Ueda (Kyoto University), and Prof. Yongsheng Chen (Georgia Institute of Technology), who discussed topics ranging from nutrient utilization in aquatic vegetation to the role of nanobubbles in urban sustainability. Industry leaders also contributed, with presentations from Dr. Michael Radicone (I2 Air Fluid Innovation) and Dr. Jeff Bodycomb (HORIBA), highlighting advancements in nanobubble characterization and real-world applications.

  • Deciphering the biodegradation mechanism of sulfonamides using combined molecular biology and computational approaches

    https://doi.org/10.1016/j.watres.2024.123037

    Dr. Zhang’s postdoc, Dr. Jiahui Hu, published a paper in Water Research and elucidating biodegradation mechanisms and predicting pollutant reactivities for advancing the application of biodegradation engineering to address the challenge of thousands of emerging contaminants. Molecular biology and computational chemistry are powerful tools for this purpose, enabling the investigation of biochemical reactions at both the gene and atomic levels. This study employs the biodegradation of ten sulfonamide antibiotics as a case study to demonstrate the integration of genomics and quantum chemistry approaches in exploring the biodegradation behavior of emerging contaminants. The isolated functional strain, Paenarthrobacter sp., could completely degrade all ten model sulfonamides under aerobic conditions. These compounds share a 4-aminobenzenesulfonamide core but differ in N1-substituent rings. Despite structural variations, all sulfonamides follow a consistent degradation pathway, yielding aminated heterocycles as end products. This pathway involves key steps such as dehydrogenation activation, ipso-hydroxylation, and the cleavage of S-N and S-C bonds, with the latter being particularly influenced by the N1-substituents. Heterocyclic structures affect biodegradation rates by altering the electronic density at the C3 and N1 atoms of sulfonamides. Substituents with higher electron-donating potential and lower Gibbs free energy barriers for S-C and C-N bond cleavage significantly enhance biodegradation efficiency. This work not only deciphers the universal biodegradation mechanism of sulfonamides but also offers theoretical insights for predicting the biodegradation behavior and pattern of emerging contaminants. These findings contribute to the effective removal of emerging contaminants from aquatic environments, advancing the practical application of biotreatment technologies.

    This study is a collaboration with her former faculty advisors, Xiaoyan Li and Bing Li, at Tsinghua university. The research was funded by the National Key R&D Program of China (no. 2022YFE0103200), the National Natural Science Foundation of China (no. 22176107), Shenzhen Science and Technology Innovation Bureau (no. SGDX20230821091559021), and the Guangdong Higher Education Institutions Innovative Research Team of Urban Water Cycle and Ecological Safety (no. 2023KCXTD053).