DATE: September 2015
New Jersey Institute of Technology | Environmental Engineering
Wen Zhang, Ph.D., P.E., Assistant Professor
Dr. Wen Zhang is currently the faculty member of NJIT’s Newark College of Engineering in the Department of Civil and Environmental Engineering as an assistant professor. Wen is a licensed Professional Engineer (P.E.) in environmental engineering.
Since joining NJIT in fall 2012, Dr. Zhang has been actively engaged in multidisciplinary research in sustainable nanotechnology. Dr. Zhang’s research integrates nanotechnology into environmental engineering to develop innovative solutions for environmental sustainability and challenges in water-energy nexus. His PhD work has extensively focused on the environmental fate and transport of engineered nanoparticles, biological interactions, nanomaterial characterization at biointerfaces [1-7], as well as mechanisms of nanoparticle’s impacts on water disinfection .
Recently, Wen leads major efforts in the sustainable design of visible light-driven photocatalytic systems for harnessing solar energy, hydrogen evolution [9-13], and efficient degradation of emerging water contaminants. Moreover, he develops novel multifunctional nanomaterials for antimicrobial applications, microalgae harvesting for biofuel production [14-18].
Utilization of non-hazardous materials and earth abundant elements for sustainable photocatalytic reactions to produce hydrogen and remove water contaminant.
“Solar-to-fuel” photocatalysis aims to transform solar energy into chemical fuels. Hydrogen (H2) is one of the target carbon-free energy fuels. Producing H/2 from an abundant, non-toxic, and clean source such as sunlight and water is an ideal sustainable solution. Thus, developing visible light-driven photocatalytic systems is increasingly important owing to the promising potential of harnessing solar energy and removing environmental pollutants concurrently. In Dr. Zhang’s research, carbon doped TiO2 was synthesized and anchored to graphene oxide (GO) to form a hybrid nanostructure. Such nanostructured photocatalysts exhibited enhanced visible light absorbance and photocatalytic H2 production rates even in the absence of noble or rare earth metals as co-catalysts. As opposed to rare earth elements, noble, or transition metals such as Pt, Pd, Ru, and Rh in the synthesis of photocatalysts, non-metal elements such as such as C, N, and S are likely the ideal options to achieve greater sustainability as they are earth abundant. For example, graphene is a unique carbonaceous nanomaterial providing a two-dimensional (2-D) sheet that was shown to greatly facilitate charge transfer and separation and thus improved photocatalytic activity. Moreover, graphene as a supporting matrix increased photocatalytic longevity and maintained good colloidal stability. Dr. Zhang’s new findings lay groundwork toward the design of sustainable and efficient hybrid photocatalytic materials for renewable energy harvesting. Novel visible light responsible materials made with earth abundant elements should also play a critical role in reaching environmental sustainability and broader applications such as antimicrobial functions, pathogen removal, and recalcitrant water contaminant removal.
Implementation of green chemistry and engineering principles in biomass separation and treatment for algal biofuel production
Microalgae are not only the promising feedstock for biodiesel production, but also a water contaminant that negatively affects water quality (harmful algal bloom). Thus, efficient algal separation or removal from water is not only critical for biofuel production but also important for drinking water security. Magnetophoretic separation is a promising technology for rapid biomass separation from water. Dr. Zhang’s team performs extensive investigations of magnetic Fe3O4 nanoparticles as a core material to synthesize multiple nanocomposite materials with cationic polymers and semiconductor nanomaterials. Their research indicates magnetic nanocomposite materials could help achieve exceptional algal harvesting efficiency with competitive economic viability. More importantly, Dr. Zhang recently developed a technique based on the UV-induced surface hydrophobicity shift to recover and reuse these magnetic agents as shown in the figure above , which potentially reduces the algal harvesting cost. Recovery of nanoparticles from algal biomass using green chemistry methods may also find many other engineering applications that require recovery, recycle and reuse of valuable nanomaterials.
The roles of Hamilton’s syringes
An integral part of Dr. Zhang’s research in the areas of photocatalysis and algal biofuel research has involved the use of gas chromatography (GC) and high performance liquid chromatography (HPLC). These techniques are to track and quantify the concentrations of vapor substances such as H2, CO2, and some volatile organic compounds (e.g., CH3CH2OH) that are used in photocatalytic reactions. The Hamilton gastight syringes (e.g., PTFE Luer Lock Syringes, Parts No. 81320, 81520, 82520) with MTB sampling valve (Parts No. 86580) have been particularly useful in the collection of air samples. The air samples can also be stored in the syringes with a Septum Adapter (Parts No. 31335) before further analysis. The Model 1725 RN syringes (Parts No.81130) show excellent features we need for air sample injection to GC. Similarly, the liquid sampling and injection into HPLC also benefit a lot from Hamilton’s syringes such as Model 1702 N syringe (Parts No. 80275) and Model 1705 N syringe (Part No. 80985) for manual injection of different liquid sample volumes. The student researchers in Dr. Zhang’s lab have benefited a lot from the Hamilton’s syringes during their experiments. In addition to research, The student researchers in Dr. Zhang’s lab have benefited a lot from the Hamilton’s syringes during their experiments. in our teaching sessions for undergraduate and high school students during the Introduction to Environmental Engineering lab sessions and summer research programs. We demonstrated the vapor and liquid sampling to the students and the simple operation of syringes has greatly facilitated the teaching and learning processes. There is no doubt that the work being carried out by Dr. Zhang and his team at the Department of Civil and Environmental Engineering fully embraces the School’s mission of broadening research and education in sustainability. We are so happy that Hamilton and its products are helping them achieve that goal. We firmly believe that the industrial engagement and support toward academic researchers will lead more beneficial and synergistic outcomes toward building a more sustainable society.
- Li, Y., Niu, J., Zhang, W., Zhang, L. and Shang, E. Influence of Aqueous Media on the ROS-Mediated Toxicity of ZnO Nanoparticles toward Green Fluorescent Protein-Expressing Escherichia coli under UV-365 Irradiation. langmuir, 2014, 30, 2852-2862.
- Zhang, W., Li, Y., Niu, J. and Chen, Y. Photogeneration of reactive oxygen species on uncoated silver, gold, nickel, and silicon nanoparticles and their antibacterial effects. Langmuir, 2013, 29, 4647-4651.
- Li, Y., Zhang, W., Niu, J. and Chen, Y. Surface coating–dependent dissolution, aggregation, and ROS generation of silver nanoparticles under different irradiation conditions. Environmental Science & Technology, 2013, 47, 10293–10301.
- Zhang, W., Hughes, J. and Chen, Y. Impacts of hematite nanoparticle exposure on biomechanical, adhesive, and surface electrical properties of E. coli cells Applied and environmental microbiology, 2012, 78, 3905-3915.
- Zhang, W., Rittmann, B. and Chen, Y. Size effects on adsorption of hematite nanoparticles on E. coli cells. Environ. Sci. Technol., 2011, 45, 2172-2178.
- Zhang, W., Stack, A.G. and Chen, Y. Interaction force measurement between E. coli cells and nanoparticles immobilized surfaces by using AFM. Colloids Surf., B, 2010, 82, 316-324
- Zhang, W., Kalive, M., Capco, D.G. and Chen, Y. Adsorption of hematite nanoparticles onto Caco-2 cells and the cellular impairments: effect of particle size. Nanotechnology, 2010, 21, 355103.
- Zhang, W. and Zhang, X. Adsorption of MS2 on oxide nanoparticles affects chlorine disinfection and solar inactivation. Water Research, 2015, 69, 59-67.
- Zhang, G., Zhang, W., Minakata, D., Wang, P., Chen, Y. and Crittenden, J. Efficient photocatalytic H2 production using visible-light irradiation and (CuAg)xIn2xZn2(1 − 2x)S2 photocatalysts with tunable band gaps. International Journal of Energy Research, 2014, 38, 1513-1521.
- Zhang, G., Zhang, W., Crittenden, J., Minakata, D., Chen, Y. and Wang, P. Effects of inorganic electron donors in photocatalytic hydrogen production over Ru/(CuAg) 0.15 In0. 3Zn1. 4S2 under visible light irradiation. Journal of Renewable and Sustainable Energy, 2014, 6, 033131.
- Zhang, G., Zhang, W., Minakata, D., Chen, Y., Crittenden, J. and Wang, P. The pH effects on H2 evolution kinetics for visible light water splitting over the Ru/(CuAg)0.15In0.3Zn1.4S2 photocatalyst. International Journal of Hydrogen Energy, 2013, 38, 11727-11736.
- Zhang, G., Zhang, W., Crittenden, J.C., Chen, Y., Minakata, D. and Wang, P. Photocatalytic hydrogen production under visible-light irradiation on (CuAg)0.15In0.3Zn1.4S2 synthesized by precipitation and calcination. Chinese Journal of Catalysis, 2013, 34, 1926-1935.
- Zhang, G., Zhang, W., Wang, P., Minakata, D., Chen, Y. and Crittenden, J. Stability of an H2-producing photocatalyst (Ru/(CuAg)0.15In0.3Zn1.4S2) in aqueous solution under visible light irradiation. International Journal of Hydrogen Energy, 2012, DOI: 10.1016/j.ijhydene.2012.11.033.
- Ge, S., Agbakpe, M., Zhang, W., Kuang, L., Wu, Z. and Wang, X. Recovering Magnetic Fe3O4-ZnO Nanocomposites from Algal Biomass Based on Hydrophobicity Shift under UV Irradiation. ACS Applied Materials & Interfaces, 2015, 7, 11677–11682.
- Ge, S., Agbakpe, M., Zhang, W. and Kuang, L. Heteroaggregation between PEI-Coated Magnetic Nanoparticles and Algae: Effect of Particle Size on Algal Harvesting Efficiency. Acs Applied Materials & Interfaces, 2015, 7, 6102-6108.
- Ge, S., Agbakpe, M., Wu, Z., Kuang, L., Zhang, W. and Wang, X. Influences of Surface Coating, UV Irradiation and Magnetic Field on the Algae Removal Using Magnetite Nanoparticles Environmental Science & Technology, 2014, 49 1190–1196.
- Agbakpe, M., Ge, S., Zhang, W., Zhang, X. and Kobylarz, P. Algae harvesting for biofuel production: Influences of UV irradiation and polyethylenimine (PEI) coating on bacterial biocoagulation. Bioresource Technology, 2014, 166, 266–272.
- Zhang, W., Zhang, W., Zhang, X., Amendola, P., Hu, Q. and Chen, Y. Characterization of dissolved organic matters responsible for ultrafiltration membrane fouling in algal harvesting. Algal Research, 2013, 2, 223-229.
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