Water processing: Light helps degrade hormones

Date:
April 22, 2022
Source:
Karlsruher Institut fu"r Technologie (KIT)
Summary:
Micropollutants in water often are hormones that accumulate in
the environment and may have negative impacts on humans and animals.

Researchers have now developed a process for the photocatalytic
degradation of these pollutants when they flow through polymer
membranes.

Irradiation with light triggers a chemical reaction, as a result
of which steroid hormones are degraded on the membranes coated
with titanium dioxide.



FULL STORY ========================================================================== Micropollutants in water often are hormones that accumulate
in the environment and may have negative impacts on humans and
animals. Researchers of Karlsruhe Institute of Technology (KIT)
and Leibniz Institute of Surface Engineering (IOM) in Leipzig have
now developed a process for the photocatalytic degradation of these
pollutants when they flow through polymer membranes. It is presented
in Nature Nanotechnology. Irradiation with light triggers a chemical
reaction, as a result of which steroid hormones are degraded on the
membranes coated with titanium dioxide.


========================================================================== Wherever people are living, hormones used in e.g. contraceptives or
agriculture enter the wastewater. Steroid hormones, such as sex hormones
and corticosteroids, may accumulate in the environment and adversely
affect humans and animals, as they impair behavioral development and
fertility. Sex hormones, for instance, may cause male fish to develop
female sexual characteristics. It is therefore important to remove
hormones, together with other micropollutants, from the wastewater before
they enter the natural water cycle again, from which drinking water
is extracted. "Supplying people with clean drinking water presently
is one of the most important challenges worldwide," says Professor
Andrea Iris Scha"fer, Head of KIT's Institute for Advanced Membrane
Technology (IAMT). "Micropollutants represent a big threat for our
future, as they impair our fertility and brain function." Inspired by
Solar Cell Technology For years, Scha"fer has studied water processing
by nanofiltration. For this purpose, she uses polymer membranes with nanometer-sized pores. However, nanofiltration requires high pressure
and, hence, much energy. Moreover, micropollutants may accumulate in the polymer membrane materials and gradually enter the filtered water. Even
if the pollutants are separated completely, a flow of concentrated
pollutants may develop and require further treatment.

Inspired by solar cell technology, the field of work of Professor Bryce S.

Richards from KIT, Scha"fer had the idea to coat polymer
membranes with titanium dioxide and to design photocatalytic
membranes. Photocatalytically active titanium dioxide nanoparticles are
applied to microfiltration membranes, whose pores are somewhat larger
than in nanofiltration. Irradiation with light then triggers a chemical reaction, as a result of which steroid hormones are degraded on the
membranes. Together with her team at IAMT and colleagues from the Leibniz Institute of Surface Engineering (IOM), Leipzig, Scha"fer has now realized
her idea and presented the new technology inNature Nanotechnology.

Catalyst for Water "We have developed a catalyst for water," Scha"fer summarizes her work. Using the photocatalytic polymer membranes, steroid hormones were removed in the continuous flow mode down to the analytical detection limit of 4 ng/l. In fact, the concentrations measured were very
close to 1 ng/l, the limit given in the new Drinking Water Guideline of
the WHO. The researchers are now optimizing their technology by reducing
the time needed and energy consumed. Moreover, their focus lies on
using natural light. In particular, their research is aimed at degrading
other pollutants by photocatalysis, such as industrial chemicals like perfluoro-alkylated and polyfluorinated substances (PFAS) or pesticides,
such as glyphosate. Another goal is to upscale the technology.


========================================================================== Story Source: Materials provided by
Karlsruher_Institut_fu"r_Technologie_(KIT). Note: Content may be edited
for style and length.


========================================================================== Journal Reference:
1. Shabnam Lotfi, Kristina Fischer, Agnes Schulze, Andrea I. Scha"fer.

Photocatalytic degradation of steroid hormone micropollutants by
TiO2- coated polyethersulfone membranes in a continuous flow-through
process.

Nature Nanotechnology, 2022; 17 (4): 417 DOI:
10.1038/s41565-022-01074-8 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/04/220422094315.htm

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