A breakthrough in water treatment

Two tiles - the hierarchical porous tio2 fibres and the gold nanoparticles


'Our designed materials are neat, robust and economical.  They offer a promising solution to the persistent pursuit of high-performance photocatalysis with appreciable recyclability, which paves the way for more sustainable and eco-friendly wastewater treatment processes'

Professor Nicole Grobert

A team led by Oxford University scientists has designed and created hierarchically porous titanium dioxide (TiO2) fibres that demonstrate exceptional promise for photocatalytic wastewater treatment.  This work is reported in a paper published in Materials & Design ('Hierarchical porosity design enables highly recyclable and efficient Au/TiO2 composite fibers for photodegradation of organic pollutants').  


More powerful water treatment is urgently needed to eradicate the diversified pollutants in wastewater.  TiO2 nanomaterials have long been recognised for their potential in photocatalytic degradation of organic pollutants.  Their industrial and municipal wastewater treatment applications, however, have been hampered for decades because the best-performance materials (ie small in size, large surface area and easy to disperse) are very challenging to separate from water and re-use without losing their performance.

"TiO2 fibres, with nanoscale diameters and much longer lengths, are much easier to filter out from water, yet problems remain in that their unsatisfied photoactivity is inferior to nanoparticles, and the weak structures tend to collapse during photoreaction and circulation." 

Shiling Dong (DPhil student and first author)

The Oxford research team from this department has demonstrated a new fibre-generating technique, so-called dual-templating electrospinning, leading to fibres with controllable hierarchical porosity.  These newly developed materials effectively capture phonon energy, and the pores throughout the fibre structure act as channels to allow water to flow through.  After combining with performance-boosting gold nanoparticles, the composite fibres achieve high efficiency and good recyclability, solving the long-standing challenges in developing practical photocatalysts for water treatment.

'TiO2 nanopowders tend to disperse or aggregate in water non-reversibly, becoming less functional after even the first use.  While the composite fibres in our work are recollected through natural sedimentation, remarkably, their superior performance remains intact for at least six cycles'.

Dr Barbara Maciejewska (the study's lead)

The development of these hierarchically porous TiO2 fibres represents a significant leap in the field of photocatalytic wastewater treatment.  The researchers continue to explore the possibilities of their newly established synthesis approach, unveiling more innovative materials to address the critical need for cleaner water worldwide.


Pictured above: scanning electron micrographs and a digital photo of the hierarchical porous TiO2 fibres (left) and transmission electron micrographs of the gold nanoparticles (Au NP5)/TiO2) composite fibre (right).