Research

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.

Novel Desalination and Water Purification Technologies

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.

  • Nanophotonics Enhanced Membrane Distillation

    Supported by NEWT and SunShot 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 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 phtothermal materials, and optimizing the process design to increase the heat recovery,  to ultimately imporve the energy-efficiency and the cost-effectiveness of NESMD.

  • 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.

  • Membrane Distillation for Organic Wastewater Treatment

    Waste heat containing significant amounts of latent heat, which can be used for membrane distillation to further increase the energy efficiency. Supported by PepsiCo, our group explores the potental of air gap membrane distillation in treating the organic wastewater.

Nanomaterials for Electrosorption and Electrocatalysis

  • Selective Transport of High-value Metals

    Concentrating and harvesting high-value metals (e.g. Li, Cu) from water has become a potential solution to meet the growing demand. For example, the lithium storage in US geothermal brine is estimated to meet over 40% of global lithium demand. However, the direct extraction is still difficult due to the low concentration of target species and complex water composition. Therefore, our group aims to develop the next-generation materials with high selectivity, together with the optimized process and system design, to achieve the selective extraction of high-value metals both energy-efficiently and cost-effectively.

    The LiSED, a lithium selective electrodialysis system we propose is advancing to Phase 2 of the American-Made Geothermal Lithium Extraction Prize.

  • 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.) 

  • Electrocatalytic Reduction of Oxyanions

    Oxyanions (NO3–,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. 

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.

  • Scale Formation Mechanism

    Membrane scaling, known as inorganic fouling, is mainly caused by particulate matter deposition or the salts precipitation on the membrane surface. It has been the primary constraint especially in seawater desalination and brine water treatment. We devote to understand the fundamental mechanism of the scale formation process at the liquid-solid interface, aiming to empower the innovation in material development and process design.

  • Dynamic Coatings and Electrified Systems for Scaling Control

    Stimuli responsive polymers(SRPs), or smart polymers, are capable of conformational or chemical changes responding to external stimulus, such as temperature, pH, light, electric or magnetic field. Such structual change may have a potential in scaling control which is yet to be explored. Supported by The Bureau of Reclamation, we propose to develop membrane coatings consisting of stimuli-responsive block copolymer brush (SRBCB)-nanomaterial complexes for active control of mineral scaling in membrane desalination systems using a periodic electrical or magnetic signal. 

     

  • 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. Our group has investigated and developed various sustainable biofouling control strategies over the years, which are icorporating nanoparticles (such as Ag, Cu etc), employing biofouling control reagents such as D-amino acids, modulating  the qurum sensing and introducing surface patterning on the mateirals. 

Antibiotic Resistance and Control in Wastewater Treatment

Propagation of Antibiotic Resistance in Wastewater Treatment: Impact of Treatment Processes and Operating Conditions

This is HEARD PIRE project founded by NSF collaborated with Virginia Tech and other national and international universities.

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.

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. 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.

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