JWPE 3-Minute Pitch "My Life in Water" event winning presentations

The increasing demand for lithium, driven by its vital role in energy storage technologies, underscores the need for efficient and sustainable recovery methods. Capacitive deionization (CDI) has emerged as a promising technology for lithium recovery from aqueous resources, such as seawater desalination brine, due to its low energy consumption, operational simplicity, and high adsorption efficiency. However, the selective recovery of lithium remains challenging due to the presence of massive competing ions. This presentation highlights my PhD research on enhancing lithium selectivity in CDI through three innovative strategies: employing nanomaterials with subnano-scale channels to leverage the size sieving effect, introducing functional groups with strong cation affinities, and utilizing lithium-ion sieves that exploit the material's memory effect. Experimental findings, detailed mechanism analyses, and potential applications for sustainable resource recovery will be discussed, paving the way for environmentally friendly lithium extraction solutions.

Track-etched membranes (TEM) offer distinct advantages over conventional membranes and other solid supports due to their precisely determined structure and the fact that their pores sizes and thickness can be varied in a controllable manner. Composite membranes were fabricated by combining the products of ion-tracking and electrospinning processes. Swift heavy ions generated from a cyclotron were used to irradiate polyethylene terephthalate (PET) polymer film to create latent tracks which were then chemically etched in an alkaline solution, to produce tracks on the membrane. Magnetron sputtering was then used to deposit titanium (Ti) on the membrane to produce PET-TM. Ligand functionalized polyacrylonitrile nanofibres (PAN-nfs), polysulfone (PSN-nfs) and polystyrene (PSRN-nfs) were directly electrospun on the Ti coated PET-TEM using an electrospinning process creating the composite membrane. These track-etched membranes with specific pore sizes were functionalized with various ligands for scavenging Pt, Rh and Ir metal anions from mine waste water. The track-etched membrane, the nanofibres and the composite membrane were characterised using SEM, TEM, TGA, ATR-FTIR and adsorption/desorption of nitrogen techniques. Mean pore size and pore size distribution was determined using electrical conductivity and small angle X-ray scattering techniques. The results confirmed the fabrication of nanofibers-coated track-etched composite membranes. Filtration studies were conducted to assess the efficiency of the uptake of the platinum group metals and invariably separate Pt, Rh and Ir from mine wastewater.

Microbial electrosynthesis (MES), coupling the electrochemical process with bio-technology, is green and specific for CO2 reduction, for which the microbial cells as the biocatalyst attached on the cathode are self-sustaining, stable, and inexpensive to develop and maintain. The MES system is a hybrid of a bioreactor and an electrochemical reactor, which requires thorough understanding across its various aspects such as reactor optimization, electrode design, and process control. In this study, the preferred inorganic carbon form (gaseous CO2 or dissolved bicarbonate) for the MES system was discussed, highlighting the importance of CO2 supplying strategy to the start-up and steady operation of the MES system. The system performance and microbial communities suggested that feeding more gaseous CO2 would aid in microbial CO2 electroreduction. Furthermore, a facile and promising electrode modification strategy was developed for MES system with Fe-Mn bimetallic oxides, increasing the acetate production rate from 28 to 78 g/(m2·d). The underlying mechanisms were also highlighted, in particular the contributions of Mn and Fe individually and their synergistic effect on the microbial CO2 electroreduction, as well as the functional microbial species and the electron transfer pathways involved. Overall, this presentation will provide effective strategies and mechanistic insights for efficient and sustainable conversion of CO2 to valuable platform organic chemicals, bringing the world closer to achieving carbon neutrality.