Hydraulic energy transformation: A new hope for water treatment challenges

A recent publication in Engineering has brought to light an innovative concept that could reshape the water - treatment landscape. The research, led by a team of scientists from Nanjing University, explores the in situ conversion of universal hydraulic energy to electricity as a solution to common challenges in water treatment.

Water treatment processes are essential for managing water quality, but they come with a set of problems. Although diverse technologies are in use, the large amount of hydraulic energy present in these processes often goes to waste. Meanwhile, the application of external electricity in water treatment faces hurdles like inconvenient operation, high energy consumption, and unwanted faradic reactions in aqueous systems.

Enter piezoelectricity. It serves as a direct hydraulic energy - harvesting mechanism that can achieve force - electricity conversion. Piezoelectric materials, when exposed to mechanical strain, generate an asymmetric shift of charges or ions, enabling the conversion of hydraulic pressure into electricity. Thanks to their high electromechanical coupling capacity, high power density, and ability to function across a wide range of frequencies, they are considered a promising strategy for addressing water - treatment challenges.

The study highlights several key applications of this technology. Firstly, self - cleaning piezomembranes show great potential. Pressure - driven membrane technology is widely used in water treatment, but membrane fouling remains a major obstacle. By integrating piezoelectric materials into membranes, hydraulic pressure pulses can be transformed into electroactive responses. This results in the generation of reactive oxygen species and dielectrophoretic forces, which help in degrading and repelling pollutants without the need for additional chemical cleaning agents or external stimuli.

Secondly, piezoelectricity can regulate catalytic reactions. In heterogeneous catalysis, modulating the electronic structure of catalysts is crucial for precise catalytic regulation. The in situ electric field created by piezoelectricity can effectively adjust the activation and conversion of molecules, as well as their activity and selectivity in various catalytic reactions. For instance, a floatable piezo - photocatalytic platform has been shown to achieve significant self - purification of polluted rivers by harnessing natural water waves and solar light.

Finally, sludge piezo - dewatering and sterilization are areas where this technology can make a big difference. Current sludge dewatering methods are expensive and energy - intensive, often causing secondary pollution. Piezo - dewatering, driven by the natural pressure during the dewatering process, can lead to electroporation of microbial cell membranes, electro - osmosis, and electromigration, promoting both dewatering and sterilization.

Although this concept shows great promise, there are still challenges to be addressed. The fundamental physicochemical transduction mechanism needs further elucidation, and the long - term stability and recyclability of piezoelectric materials in aqueous environments are areas that require more research.

This new approach offers a glimmer of hope for a more sustainable, efficient, and cost - effective water - treatment future.

The paper “In Situ Conversion of Universal Hydraulic Energy to Electricity to Address Common Challenges in Water Treatment,” authored by Qiancheng Xia, Xinrong Fang, Jiaming Yao, Xiaohan Yang, Yongguang Bu, Wenkai Zhang, Guandao Gao. Full text of the open access paper: https://doi.org/10.1016/j.eng.2024.11.009. For more information about the Engineering, follow us on X (https://twitter.com/EngineeringJrnl) & like us on Facebook (https://www.facebook.com/EngineeringJrnl).