Research

Reinvent membranes at the nexus of novel material, structural redesign, and fabrication approach

Membrane separation is one key process in advanced water treatment due to various technical advantages such as small footprint, high separation efficiency, and relatively affordable costs. However, their more widespread applications are hindered by several technical challenges such as a trade-off between permeability and selectivity, fouling, and low chlorine resistance, among others. These challenges can be effectively addressed by developing a new generation of membranes, enabled by the use of novel membrane materials, the redesign of membrane structure, and the engineering of advanced fabrication approaches. We are actively exploring the assembly of emerging membrane building blocks (such as carbon and catalytic nanomaterials, polyelectrolytes) into novel membrane structures (mixed matrix or layer-by-layer assembly), assisted by new scalable aerosol-assisted printing approaches. Our current research has been focused on the development of nanocomposite ultrafiltration (UF) and polyelectrolyte multilayer nanofiltration (PEM NF) membranes.

Ongoing projects:
1. Polyelectrolyte Nanofiltration Membranes via Aerosol-assisted Printing: Establishing Fabrication-Structure-Performance Relationships towards Scalable Manufacturing and Applications in Advanced Water and Wastewater Treatment (Funded by Hong Kong RGC GRF, 2023-2025)
2. Development and Application of Nanocomposite Membranes via 3D Printing for Water Treatment (Funded by Shenzhen STIC, 2022-2024)
Completed projects:
1. Advanced Nanocomposite Membranes Synthesized by An Aerosol-assisted Fabrication Approach for Water and Wastewater Treatment (Funded by Hong Kong RGC ECS, 2020-2023)
2. Carbon Nanomaterials-Polysulfone Nanocomposite Ultrafiltration Membranes: Revealing Synthesis-Structure-Performance Relationships (Funded by NSFC, 2020-2022)

Reimagine the potential of magnetic water treatment

A magnetic field has been studied previously in promoting the reaction rates of an advanced oxidation process like the Fenton reactions, where the placement of a magnet near the batch reactor typically enhances the transfer of electrons and/or corrosion of iron materials, thus accelerating the reaction rates. But the significant potential of applying a magnetic field to achieve effective water treatment remains largely untapped. We proposed a new concept centered on magnetic confinement-enhanced water treatment, where magnetic microscale or nanoscale materials are immobilized and assembled in various magnetic fields, which opens up opportunities to build unprecedented yet superior water treatment systems.

Ongoing project:
Enhancing and Sustaining Zerovalent Iron Reactivity for Arsenic Removal in a Magnetic Confinement-enabled Flow-through Water Treatment System (Funded by Hong Kong RGC GRF, 2024-2026)

Revisit colloidal behaviors of engineered nanomaterials

Engineered nanomaterials (ENMs) are manufactured materials with at least one nanoscale (1−100 nm) dimension. Their small size and high surface area-to-volume ratio often lead to high surface energy and colloidal instability (i.e., aggregation) compared to their bulk counterparts. Aggregation of ENMs reduces available surface area and in turn alters their functionality, reactivity, and toxicity. For example, the stability of ENMs in water or organic solvents is crucial to our membrane applications. As such, tremendous research efforts have been devoted to the understanding of various factors that affect nanomaterial aggregation, theoretical prediction, and the development of engineering approaches such as surface coating to enhance nanomaterial stability. We aim to reveal structure-reactivity type relationships regarding nanomaterial aggregation, using a combination of experimental, theoretical, and data-driven meta-analysis approaches. We are also investigating a particular type of functional surface coating – engineered DNA. Our research findings enable their performance optimization in practical aquatic applications (e.g., from DNA design to pretreatment strategy).