Research in the Li Lab for Advanced Water Treatment Technologies focuses on novel materials, processes as well as system-level designs that enable energy efficient, cost-effective utilization of conventional and alternative water resources for residential, municipal and industrial water supplies. We exploit discoveries in fundamental research at the interface of materials science, water chemistry, microbiology, transport phenomenon, and reactor engineering, to empower and drive technological innovation in water and wastewater treatment. At the fundamental science level, we are interested in understanding transport of contaminants in nanomaterials and nano-structured materials including nanosorbents, membranes and electrodes. In technology development, we focus on novel nanocomposite membrane and electrode materials for high efficiency desalination and ionic contaminant removal. A particular interest is the harvest of renewable energy, e.g., sunlight, for desalination and water purification. At the systems level, we develop analytical tools and comprehensive mathematical models to characterize urban water and wastewater infrastructure systems in different system configurations.
Membrane Fouling: Mechanisms, Advanced Materials and Control Strategies
Membrane fouling, categorized as organic fouling, inorganic fouling and biofouling, is a major issue impeding the application of membrane technology to water treatment processes. It not only increases the mass transfer resistance but also causes deterioration of effluent quality and ultimately shortens the membrane’s useful life. Therefore, it is important to study the basic mechanisms fundamentally for the development of functionalized anti-fouling membranes.
Combined Fouling Mechanisms
Natural water bodies are complex systems. When they are treated with membranes, the fouling normally shows largely different from that of feed water with only one or two species, which makes the fouling issue hard to predict and control. In our lab, complex mechanisms of combined colloidal and organic fouling in high pressure membrane systems are studied via experimental measurement and mathematical modeling.
1. Law, C.M.C., Li, X.Y. and Li, Q.* The Combined Colloid-Organic Fouling on Nanofiltration Membranes for Wastewater Treatment and Reuse. Separation Science & Technology, 2010, 45(7): 935-940.
2. Kim, A.*, Contreras, A., Li, Q. and Rong, Y. Fundamental Mechanisms of Three-Component Combined Fouling with Experimental Verification. Langmuir, 2009, 25(14): 7815-7827.
3. Contreras, A., Kim, A. and Li, Q.* Combined Fouling Behavior of Nanofiltration Membranes: Mechanisms and Effect of Organic Matter. Journal of Membrane Science, 2009, 327(1-2): 87-95.
4. Li, Q.* and Elimelech, M. Synergistic effects in Combined Fouling of a Loose Nanofiltration Membrane by Colloidal Material and Natural Organic Matter. Journal of Membrane Science, 2006, 278: 72-82.
Effect of Membrane Surface Properties on Scale Formation
Membrane scaling, known as inorganic fouling, is mainly caused by particulate matter deposition or the salts precipitation on the membrane surface. It has been a key issue especially in seawater desalination and brine water treatment. Ongoing researches mainly study the effect of membrane surface properties on the heterogeneous nucleation. Characterized by QCM-D, different nucleation rates were observed on the surface with different functional groups.
Sustainable Control Strategies for Membrane Biological Fouling
Due to the adaption and inevitable growth of microorganisms, biofouling is a critical issue in the operation and maintenance of membrane systems used for water and wastewater treatment. Nanoparticles(such as Ag, Cu etc) are extensive studied biocidal releasing materials. Thus, they are consumable and the water safety after ion releasing is a concern as well. Our group focus on the sustainable biofouling control strategies, by reducing Ag releasing rate1,2 and employing biological biofouling control reagents such as D-amino acids.3,4
1. Wu, J., Yu, C. and Li, Q.* Novel Regenerable Antimicrobial Nanocomposite Membranes: Effect of Silver Loading and Valence State. Journal of Membrane Science, 2017, 531: 68-76.
2. Wu, J., Yu, C. and Li, Q.* Regenerable antimicrobial activity in polyamide thin film nano-composite membranes, Journal of Membrane Science. 2015, 476: 119-127.
3. Yu, C., Wu, J., Zin, G., Di Luccio, M., Wen, D. and Li, Q.* D-Tyrosine Loaded Nanocomposite Membranes for Environmentally-Friendly, Long-Term Biofouling Control. Water Research, 2018, 130: 105-114.
4. Yu, C., Wu, J., Contreras, A.E. and Li, Q.* Control of Nanofiltration Membrane Biofouling by Pseudomonas aeruginosa Using D-Tyrosine. Journal of Membrane Science, 2012, 423–424 (15): 487-494.
Novel Desalination and Water Purification Technologies
Nanophotonics Enhanced Membrane Distillation
Supported by NEWT and Sunshort Program from Department of Energy, our group has developed Nanophotonics-enabled solar membrane distillation (NESMD) which greatly reduces the operation cost of MD by using sunlight as a heat source to heat up the feed water. It also provides a highly localized heating on membrane surface which reveres the temperature polarization on the feed side and increases the energy efficiency. In our lab, we actively work on developing novel materials for NESMD to improve the sunlight absorbance, mechanical durability, and chemical stability, and cost of photothermal material for NESMD. Current research involves developing core-shell structure carbon black coated nanofiber for improved NESMD performance.
1. Wu, J., Zodrwo, K.R., Szemraj, P., and Li, Q.* Photothermal Nanocomposite Membranes for Direct Solar Membrane Distillation. Journal of Materials Chemistry A, 2017, 5(45): 23712-23719
2. Dongare, P.D., Alabastri, A., Pedersen, S., Zodrow, K.R., Hogan, N.J., Neumann, O., Wu, J., Wang, T., Deshmukh, A., Elimelech, M., Li, Q.*, Nordlander, P., Halas, N.J.* Nanophotonics –Enabled Solar Membrane Distillation for Off-grid Water Purification. PNAS, 2017, 114 (27): 6936-6941. (doi:10.1073/pnas.1701835114)
Water Recovery From Urine in Space Missions
One of the significant challenges facing future long-range space exploration is the need to provide adequate water supplies with minimal resource input from Earth. To meet this challenge, it is important to develop robust technology that can extract >90% of the water from the urine produced by crew members. Membrane distillation (MD) has shown promise for treating concentrated wastewaters at high recovery rates, but scaling can still be a problem. To develop robust, scaling-resistant membranes of >90% water recovery from urine-based wastewaters, it is important we firstly characterize the scaling behavior of synthetic and real urine in a membrane distillation system using experimental and modeling approaches.
Nanocomposite Membranes for Electrothermal Membrane Distillation
Application of electrothermal surface heating material has further broaden application of MD systems, as it allows easier control and higher intensity of energy input. However, existing surface heating materials face major challenges in MD: low electrochemical stability and unable for high energy input. In our group, we developed a novel electrothermal surface heating element by in situ growth of nano-thin protective coating, which provides high thermal conductivity, high electric insulation, and anti-corrosion properties, all critical for application in saline solutions.
1. Kuichang Zuo, Weipeng Wang, Akshay Deshmukh, Shuai Jia, Hua Guo, Ruikun Xin, Menachem Elimelech, Pulickel M. Ajayan*, Jun Lou*, Qilin Li*, Multifunctional nanocoated membranes for high rate electrothermal desalination of hypersaline water (Under Review)
Interactions of Electrolyte Ions with Heterogeneous Surfaces of Carbon Nanomaterials
Nanomaterials for Electrosorption and Electrocatalysis
Nanocomposite Electrodes for Selective Ionic Contaminant Removal
Capacitive deionization (CDI) is an emerging desalination and water treatment process, which efficiently removes hardness or any ionic species in water/wastewater through electro-sorption, with the advantage of lower energy consumption, less chemical usage, and lower fouling potential. By adopting ion-selective polymer coating, our group aims to develop novel CDI realizing the selective removal of multivalent ions over monovalent ions, such as scalants (Ca2+, SO42- etc.) or toxic heavy metals (Cr (VI), As (V) etc.)
1. Zuo, K., Kim, J., Jain, A., Wang, T., Verduzco, R., Long, M. and Li, Q.* Novel Composite Electrodes for Selective Removal of Sulfate by the Capacitive Deionization Process. Environmental Science & Technology, 2018, 52: 9486 – 9494.
2. Jain, A., Kim, J., Owoseni, O.M., Weaters, C., Caña, D., Zuo, K., Walker, W.S., Li, Q.*, and Verduzco, R.* Aqueous-Processed, High-Capacity Electrodes for Membrane Capacitive Deionization. Environmental Science & Technology, 2018, 52(10): 5859 – 5867.
Electrocatalytic Reduction of Oxyanions
Oxyanions (ClO4– etc.) and organic pollutants (PFOA, PFOS etc.) are usually much lower in concentration but higher in toxicity. Therefore, developing high selective and efficient removal technologies for target contaminants is of great significance. By modifying selective nanomaterials or efficient catalysts, CDIs can realize selective removal of target containments by electrosorption, electrochemical oxidation/reduction, or alternative electrosorption, oxidation and reduction.
Antibiotic Resistance and Control in Wastewater Treatment
Propagation of Antibiotic Resistance in Wastewater Treatment: Impact of Treatment Processes and Operating Conditions
Inactivation of Antibiotic Resistant Bacteria and Genes
Due to numerous causations including over-prescribing of antibiotics and over-use in farming, antibiotic resistant bacteria (ARB) and antibiotic resistant genes (ARG) are found in various environments which eventually are concluded in wastewater treatment plants (WWTPs). Infected WWTP effluents are then dispersed to a variety of areas in the environment-leading to a greater spread of ARBs. Therefore, disinfection processes for ARBs and ARGs particularly in WWTPs is an area of critical focus. We aim to figure out effective disinfection method such as advanced oxidation processes, especially for the ARBs and ARGs.
Biofilms in Water Treatment Systems
Impact of Materials Surface Morphology on Bacteria Biofilm Formation
Cell adhesion is the first and key step leading to biofilm formation. Material surface properties, such as hydrophilicity and morphology, act significantly in the interaction between cells and materials. Enlightened by the antifouling and self-cleaning properties of plants such as Nelumbo nucifera (lotus) and Colocasia esculenta (taro), researches found the surface topography would greatly affect the adhesion performance. With nano-structured surface, the anti-adhesion property could even be retained under fully wetting condition. Therefore, engineered surfaces with properly designed nanoscale topographic structures could potentially reduce or prevent particle/bacterial fouling under submerged conditions.
1. Yu, C., Ma, J., Zhang, J., Lou, J., Wen, D., Li, Q.* Modulating Particle Adhesion with Micro-patterned Surfaces. ACS Applied Materials and Interfaces. 2014, 6(11): 8199-8207.
2. Ma, J., Sun, Y., Gleichauf, K., Lou, J. and Li, Q.* Nanostructure on Taro Leaves Resists Fouling by Colloids and Bacteria under Submerged Conditions. Langmuir, 2011, 27: 10035-10040.
Quorum Sensing in Biofilm Formation and Its Control
Quorum Sensing (QS), the cell to cell communication strategy to coordinate collective behavior, through bacteria synthesized diffusible signals(autoinducers), could be utilized to regulate the biofilm formation. We enhanced anodic biofilm formation by promoting quorum sensing (QS) through addition of exogenous QS signals. Therefore, QS stimulation through the addition of trace levels of such autoinducers might be a feasible approach to enhance MFC performance under high-salinity conditions.
1. Monzon, O., Yang, Y., Li, Q. and Alvarez, P.J.J.* Quorum Sensing Autoinducers Enhance Biofilm Formation and Power Production in an Axenic Hypersaline Microbial Fuel Cell. Biochemical Engineering Journal. 2016, 109: 222-227.
Effects of D-amino Acids on Bacterial Biofilms
D-amino acids produced by bacteria could inhibit biofilm formation and trigger self-dispersal of biofilms without affecting bacterial growth, presenting a potentially low cost, non-toxic and non-biocidal approach to biofouling control. We studied the distinct mechanisms at different d-tyrosine concentrations on different bacteria types, even those with antibiotic genes. It suggests that D-amino acids would be potential for biological biofouling control when the dosage is carefully controlled.
1. Yu, C., Li, X., Zhang, N., Liu, C., Wen, D. and Li, Q.* Inhibition of Biofilm Formation by D-Tyrosine: Effect of Bacterial Type and D-Tyrosine Concentration. Water Research. 2016, 92: 173-179.
2. Yu, C., Wu, J., Contreras, A.E. and Li, Q.* Control of Nanofiltration Membrane Biofouling by Pseudomonas aeruginosa Using D-Tyrosine. Journal of Membrane Science, 2012, 423–424 (15): 487-494.
Sustainable Urban Food, Energy and Water Infrastructures
Quantitative Modeling Tools for Design and Performance Assessment of Integrated Water Management Systems
Safe and secure water supply is critical to the sustainability of cities. This goal, however, has become increasingly challenging due to rapid population growth, continuing urbanization and global climate change. A paradigm shift from centralized water supply to an integrated water and wastewater management approach has been proposed as a potential solution, but the discussion remains largely qualitative. The lack of quantitative assessment of the potential economic and environmental implications of such an approach prohibits data-driven policy-making and hinders technological development and implementation. We aim to develop quantitive models to assess urban water and wastewater infrastructure through decentralized direct potable reuse (DPR) of wastewater as a strategy to improve energy and water efficiency of urban water systems.
Engineering Implementation of Nanotechnologies for Water and Wastewater Treatment
Supported by NEWT, the project is the scaling up of our bench-scale systems to demonstrate and test the application potential of these novel technologies, such as NESMD and selective CDI, under practical circumstances. It also serves an educational purpose and give undergraduates opportunities to participate in research and engineering design.