Developing chemical-free cleaning with the help of synchrotron X-rays

Every year, billions of kilograms of detergents and cleaning agents are used globally, ending up in aquatic systems and accumulating in living organisms. To further develop and improve a water filtration system for producing ultra-pure water with no added chemicals, Scandinavian Water Technology (SWATAB) and Lund University used synchrotron X-rays at MAX IV.

SWATAB has developed a so-called DIRO water filtration system that produces ultra-pure water without adding chemical cleaning agents or detergents. The system is designed for cleaning and washing and works at room temperature. It filters, purifies, and deionises incoming water so that grease and dirt lose grip on surfaces, fabrics, and laundry.

However, the mechanism of how different types of water can lift and transport particles is not yet fully understood. This knowledge is crucial for further optimising the system and enabling sustainable cleaning.

Using synchrotron X-rays to study water purification processes

To study this mechanism, small-angle X-ray scattering (SAXS) using synchrotron X-rays is an ideal research technique since it allows quantification of the size distribution of nanoparticles within a scattering volume such as water. It can be used to mimic the process of how water releases dirt particles from pores or surfaces.

Therefore, SWATAB teamed up with researchers from Lund University and Malmö University to perform a SAXS experiment at MAX IV, using the beamline CoSAXS.

First insights into real-time processes and changes

Samples consisting of thermoplastic chips covered in soil were produced and then washed with DIRO water, other types of ultra-pure water, and a salt solution to mimic tap water.

Using small-angle X-ray scattering (SAXS), the researchers were able to see for the very first time what happened in real-time when the ultrapure DIRO water hit the soil on the sample, lifted it, and transported it away.

The results revealed how the DIRO water was able to extract the soil nanoparticles from the microfluidic chip in a continuous manner. In contrast, the extraction rate in the other deionised water showed a variation.

Also, the DIRO water caused no degradation to the nanoparticles, as the dimension of the nanoparticles did not change.

The results indicate that DIRO water can enhance the dispersion of soil nanoparticles from a pore compared to deionised water or tap water.

Novel insights will support sustainable cleaning

The experiment illustrated significant differences between filtration systems and methods for producing ultra-pure water. DIRO water is better at causing the fabric or surface to release dirt, such as soil. This result supports earlier observations by SWATAB.

The insights will guide SWATAB’s further development of water filtration systems for producing ultra-pure water with no added chemicals, supporting sustainable cleaning.

“This project shows the importance of collaboration between the state-of-the-art synchrotron techniques, science, and the industry.”

Mats Marklund, CEO, SWATAB