The use of graphene oxide (GO) in water purification has garnered significant attention due to its large specific surface area, high mechanical strength and abundant of oxygen functional groups.[1] However, several challenges hinder its practical deployment in real-world applications including high production costs, separation difficulty after purification process, and potential environmental risks associated with graphene migration into water systems.
To address these limitations, we introduced for the first time ‘adsorption-photodegradation system’, where only a minimal amount of TiO2 and GO is coated onto sand particles to effectively mitigate challenges posed by emerging water pollutants. This approach overcomes the major bottlenecks of existing graphene-based adsorbents including poor stability in water, weak interaction between graphene and sand surface, non-uniform coating, high cost and poor pollutants removal.
TiO2-GO-sand exhibited promising removal performance for dyes and pharmaceuticals and personal care products (PPCPs), where rhodamine B (RhB) and triamterene (TA), were used as modelled water pollutants. TiO2-GO-sand not only demonstrated remarkable removal efficiency for both tested pollutants, but also outstanding regeneration efficiency with 100% removal of TA for the 1st 10 cycles and up to 99.4% removal of RhB at the 20th cycle. The developed TiO2-GO hybrid sand is highly robust over 20 repeated cycles without detectable GO and TiO2 leaching from the coated sand.
Currently, the advancement of this sustainable water purification technology is rated at TRL 4, where it is set to undergo pilot-scale production, with plans for licensing, scaling, and eventual market deployment. This transition marks a significant milestone in addressing emerging water pollutants.