Reliable access to clean water is a fundamental human right and a key goal of the United Nations’ Sustainable Development Goals. Therefore, developing technologies that eliminate pollutants from water sources is crucial for achieving sustainability. Among various methods, utilizing solar energy offers a promising solution for water purification without contributing to carbon emissions.
Currently, numerous photocatalysts are being investigated for their ability to degrade water contaminants through solar-driven processes. In contrast, photothermal evaporation harnesses solar energy to swiftly evaporate contaminated water, converting it into fresh water. However, both photocatalytic and photothermal remediation technologies often depend on costly materials that are difficult to produce and deploy on a large scale, highlighting the need for a single, affordable composite material.
A recent study conducted by a team from the Nagoya Institute of Technology (NITech) in Japan, including Dr. Kunihiko Kato, Dr. Yunzi Xin, and Mr. Yuping Xu, under the guidance of Associate Professor Takashi Shirai, introduced a new approach to create multifunctional composite particles. These particles can independently perform multiple critical functions for water purification.
The research group aims to enhance their ball milling technique to develop similar all-in-one catalysts for water purification and other uses. They utilized a planetary ball mill and fine-tuned the milling parameters to convert a commercially available powdered blend of molybdenum trioxide (MoO3) and polypropylene into composite particles consisting of hydrogen molybdenum bronze (HxMoO3–y), molybdenum dioxide (MoO2), and activated carbon.
“Our mechanochemical method outperforms existing techniques in both energy efficiency and cost-effectiveness,” notes Dr. Shirai.
Through comprehensive testing, the research team showcased the impressive capabilities of their composites. Initially, these particles demonstrated extensive light absorption across the near-infrared, visible, and ultraviolet spectrum, facilitating the photocatalytic breakdown of a model organic pollutant. Notably, the composites also acted as Brønsted acid catalysts, effectively removing water contaminants even in the absence of light.
Moreover, the proposed catalyst displayed plasmonic characteristics, resulting in a significant photothermal effect that allowed for rapid heating using sunlight. This property could be utilized to promote the swift evaporation of water with remarkable photothermal conversion efficiency. Lastly, oxygen-containing carbons produced as byproducts of milling could adsorb and eliminate heavy metal ions from wastewater.
The research team intends to further refine their ball milling technique to create similar all-in-one catalysts for water purification and additional applications.
“Our technology has the potential for a wide range of applications, including enhancing the functionality of existing materials and upcycling waste plastics to ensure access to drinking water,” concludes Dr. Shirai.
Source :Nagoya University
