For efficient water collection, amorphous inorganic hollow multishelled structures have been used. Credit: Yang Nailiang
Global water scarcity is a serious problem. Water purification requires a lot of fossil energy, and can also lead to secondary pollution.
This strategy has been deemed the most promising to address this problem. It is still challenging to develop an optimized material that can convert solar-vapor efficiently and be resistant to environmental changes.
The Institute of Process Engineering (IPE), Chinese Academy of Sciences has developed an ultra-stable, amorphous Ta2 O 5/C nanocomposite with hollow multishelled structures (HoMS) for solar evaporate. This can increase the efficiency of water purification.
The study was published by Advanced Materials on October 29.
Prof. Wang Dan, who is the corresponding author of this study, stated that "The exact atomic and composition control in HoMS's building block realizes an indirect bandgap structural with abundant energy states around Fermi levels, which enhances photothermal conversion to facilitate photothermal transformation." "The unique hollow multishelled structure, which can effectively enhance light absorption like blackbody," he said.
HoMS reduces the energy needed for water evaporation. Simulations show that HoMS creates a thermal gradient which is the driving force behind vapor evaporation.
Wang stated that HoMS also benefits water transportation. "The capillary pumping effect in HoMS encourages liquid water diffusion, and the HoMS nanopores induce water molecules to evaporate as clusters. This allows for evaporation with lower enthalpy."
A super-fast evaporation rate of 4.02 kg/m-2h-1 was achieved by highly efficient photoabsorption. This indicates a long-term stability and a rapid evaporation rate that has not changed in 30 days.
After evaporation, the pseudovirus SC2-P concentration could be reduced by six orders of magnitude.
The amorphous Ta 2O 5 /C composite can be easily fabricated, transported, stored, and then recycled. It can be used to purify seawater or water containing heavy metals or bacteria, and produce safe drinking water that meets the standards of the World Health Organization.
Scientists from IPE are currently developing a prototype for seawater desalination to be used by residents of isolated islands.
Continue reading about the mechanisms of enhanced evaporation flux via nanochannels
More information: Xuanbo Chen et.al, Highly Efficient Photothermal Converter and Water Transport During Sun Evaporation Enabled By Amorphous Hollow Multishelled Nanocomposites. Advanced Materials (2021). Journal information: Advanced Materials Xuanbo Chen et al, Highly Efficient Photothermal Conversion and Water Transport During Solar Evaporation Enabled by Amorphous Hollow Multishelled Nanocomposites,(2021). DOI: 10.1002/adma.202107400
