A large portion of Zhaohui Tong's work is with UF’s biofuels program, but Tong’s vision and capabilities go beyond biofuels. She is interested in the full range of products that can be produced from biomass. Her training gives her remarkable scope to work at all stages of biomass processing -- from pretreatment to the development of novel polymer products. In addition to her work with biomass processes, Tong maintains an active research program in the area of novel polymer and nanoparticle development.
Biofuels and Biomass-based Products
The basic problems with petroleum are well known. Still the largest energy source in the U.S. (40%) and in the world (35%), petroleum results in many environmental problems, such as acid rain, stratospheric ozone depletion, global warming, and environmental degradation. Plus, petroleum and other nonrenewable energy sources are running out and will be depleted in the future. Part of the solution to these problems is the production of biofuels, and the U.S. government has mandated the production of 36 billion gallons of biofuels by 2022 and 60 billion gallons by 2030.
Two UF biofuel plants will be part of this solution. One of the plants is a state-of-the-art research-scale biofuel pilot plant located on the UF campus, and the other is a $20 million biofuel production facility, which will be located in Perry, Florida. Tong works closely with both of these facilities – she does research in the campus pilot plant and is helping to develop the biofuel production facility. Tong is also interested in modeling and computational aspects of biofuel engineering. She collaborates with Dr. Guanghui (George) Lan in UF’s Industrial Engineering Department in an interdisciplinary research effort to simulate and optimize the biofuel feedstock supply chain and biofuel process.
But production of biofuels is not the whole story because petroleum is not just a fuel. Many chemicals and plastics are derived from petroleum. This is the “bioproducts” part of the program and one that Tong is eager to dig into. Replacing petroleum means both replacing petroleum-based fuels with biofuels and finding additional ways of reducing environmental pollution through complete utilization of current biomass and the production of high-value-added biomass-based products. Production of high-value-added materials from the three components of lignocellulose is a very interesting research area to Tong. She cites nanocrystalline cellulose which can dramatically strengthen plastics, oligosaccharides as growth regulators for animals and plants, and lignin-based products, such as nanolignin with its UV-blocking properties.
Tong’s preparation for her current position is unique and especially appropriate. Her primary interests in school were mathematics and chemistry, but she has always been motivated by a strong desire to find work of benefit to human health. She had thought she might accomplish this either directly by becoming a physician or indirectly by reducing the environmental impact of modern society. Despite these lofty goals, advisers directed her to Pulp and Paper Engineering as the most practical use of her skills, given the specific opportunities in the region of China she was living in. Nevertheless, what seemed like a diversion served as an unexpected, but appropriate preparation of her current position.
Tong describes the many benefits gained from this training and experience. Most importantly, her education and industrial experience in pulp and paper dealt with lignocellulose and natural fibers, which are also the most interesting raw materials for biofuel production. Lignocellulosic materials are not unfamiliar. This material makes up most of the mass of the plants all around us, in fact, lignocellulose is the most abundant organic material on earth.
Tong explains that lignocellulose is composed mainly of three polymers. The first is cellulose, which, in its pure state, is a fluffy, fibrous material. A cotton ball is 95% cellulose. But in combination with two other polymers, lignin and hemicellulose, a new material is formed which gives the stems of plants and the wood in trees their strength. Cellulose is the main component of woody plants (about 40-45%) with lesser amounts of lignin (20-25%) and hemicellulose (15-25%).
The detailed understanding of lignocelluloses which Tong gained in working with pulp and paper is critically important for her work with products derived from biomass. Tong explains that most current biorefinery unit operations are adapted from the pulping process, including feedstock storage and transportation, preparation, size reduction, and the pretreatment process. Her industrial experience in the paper industry with different feedstocks, different processes, and different final products exposed her to a broad range of scientific and engineering aspects of pulp production, including biomass chemistry and biomass handling and processing. Knowledge of these unit operations will be very useful for Tong as she works on the scale-up and commercialization of current biofuel technologies.
Another benefit of Tong’s work in China was that, in addition to what she learned about the main product, paper, she also learned about the processing of lignocellulose for production of alternative products and byproducts. She focused on research into the chemical pretreatment and liquefaction of lignocelluloses, ranging from pure cellulose to tough woody materials. This liquefaction product can be synthesized into value-added plastics, such as polyurethane film.
Tong significantly advanced her ability to develop novel products through her studies in the School of Chemical and Biomolecular Engineering at the Georgia Institute of Technology. Her training combined chemical engineering, polymerization, nanotechnology, and colloid and surface chemistry. Specifically, she worked to synthesize polymer composites with special properties, such as super barrier properties for water, grease, heat resistance and higher physical properties. In a breakthrough project, she worked to synthesize the self-assembling particles with core-shell structure and understand the polymerization mechanism to synthesize this type of particle. The particles she made could be stabilized in water to create a synthetic latex, which had certain desirable physical, thermal, and barrier properties. Technically speaking, Tong modified clay particles into exfoliated nanoclay layers and grafted a monomer-reactive group onto the clay surface; then, using a specialized process called miniemulsion polymerization, she encapsulated the nanoclay particles in polymer resulting in particles with size range of 200-400 nm.
In discussing the potential for novel products derived from biomass, Tong emphasizes lignin, which is a significant portion of biomass (18%-25%) and is not used to make paper or biofuel. Lignin left over from the production of paper is often burned to offset energy costs. This is a poor use of lignin for two reasons. First, it is a very energy-intensive process and generates heat with low value. Second, it is only possible to use lignin this way when it comes from specific feedstocks and is pretreated in certain ways. Current biofuel processes start with non-woody agricultural residues and are pretreated with acid, which is not suitable for this lignin mature technology. Tong would like to isolate and purify this lignin and evaluate its function as the prepolymer to synthesize high value-added, lignin-based products or composites. Then she would like to make this process part of the current biofuel pilot plant.
Through Tong’s work, the maximum possible value will be derived from the lowly biomass that the process starts with.
Dr. Tong specializes in sustainable biopolymer systems, bio-nanocomposite synthesis and self-assembling; the conversion of biomass to chemicals, fuels and bioproducts.
ABE6933: Advanced Biobased Products
Research and Extension
- Production, characterization and application of green nanocomposites
- Synthesis of sustainable latex of biopolymer encapsulated nanohybrid via miniemulison
- Development of high-value byproducts from biorefining waste and its applications in coating, packaging and agricultural areas
- Synthesis of cellulose-based biomimetic nanocomposite
- Conversion of lignocellulosic biomass to ethanol
- Synthesis of plant-based chemicals and materials
- Ph.D. Chemical Engineering, Georgia Institute of Technology 2007
- M.S. Chemical Engineering, Georgia Institute of Technology 2005
- 2010-Present: Assistant Professor, Agricultural and Biological Engineering Department, University of Florida
- 2007-2010: Process Engineer, Energy and Chemicals Business Group, CH2MHILL Engineering Ltd.
- 2003-2007: Graduate Student Research Assistant, School of Chemical & Biomolecular Engineering, Georgia Institute of Technology
Awards and Honors
- Graduate Student Fellowship, Georgia Institute of Technology, 2003-2007
- Six Sigma Cost-saving Award and Team Award for New Poduct Development, Sonoco Packaging Co. Ltd., China, 2002
Other Professional Activities
- Member, AICHE, 2008-present
- Member, TAPPI, 2002-2003
- Member, ASABE 2010-2011