Researchers develop catalyst that purifies herbicide-tainted water and produces hydrogen

An innovation developed by researchers  at Oregon State University’s College of Science which is a catalyst that  produces hydrogen while simultaneously purifying water contaminated by herbicides.

The project is significant since water pollution is a significant global issue and hydrogen is a clean, sustainable fuel.

It involved researchers from the OSU College of Engineering and HP Inc.

The results of the investigation on photoactive catalysts were released in the journal ACS Catalysis today.

“We can combine oxidation and reduction into a single process to achieve an efficient photocatalytic system,” OSU’s Kyriakos Stylianou said. “Oxidation happens via a photodegradation reaction, and reduction through a hydrogen evolution reaction.”

A catalyst is a material that speeds up a chemical reaction without changing chemically in the process.

Photocatalysts are substances that absorb light to get energy and use that energy to oxidize organic pollutants to destroy them.

Self-cleaning coatings for stain- and odor-resistant walls, floors, ceilings, and furniture are only one of the many uses for photocatalysts.

The project, which used titanium dioxide photocatalysts made from a metal-organic framework, or MOF, was directed by Stylianou, an assistant professor of chemistry.

It is composed up of positively charged metal ions  which are surrounded by organic “linker” molecules, MOFs are crystalline, porous materials with customizable structural characteristics and nanosized holes.

The properties of the MOF can be designed with a number of components.

MOFs can be calcined to produce semiconducting materials like titanium dioxide through high heating without melting.

The most widely used photocatalyst is titanium dioxide, which is present in the minerals anatase, rutile, and brookite.

Anatase doped with nitrogen and sulfur was found to be the best “two birds, one stone” photocatalyst for simultaneously producing hydrogen and degrading the widely used herbicide glyphosate by Stylianou and collaborators including Lney rnadóttir of the OSU College of Engineering and William Stickle of HP.

Since its introduction on the market in 1964 under the brand name Roundup, glyphosate, also known as N-phosphonomethyl glycine or PMG, has been extensively sprayed on agricultural fields.

“Only a small percentage of the total amount of PMG applied is taken up by crops, and the rest reaches the environment,” . “That causes concerns regarding the leaching of PMG into soil and groundwater, as well it should – contaminated water can be detrimental to the health of every living thing on the planet. And herbicides leaching into water channels are a primary cause of water pollution.”Stylianou said

Water is the most prevalent compound in which hydrogen can be found, and producing hydrogen by splitting water through photocatalysis is cleaner and more environmentally friendly than the traditional method of getting hydrogen, which involves getting natural gas through a process called methane-steam reforming, which releases carbon dioxide.

In addition to its significance in the energy sector, hydrogen has several scientific and industrial uses.

It is employed in the synthesis of numerous chemicals, including ammonia, in the creation of polymers, in fuel cells for automobiles, and in the refining of metals.

“Water is a rich hydrogen source, and photocatalysis is a way of tapping into the Earth’s abundant solar energy for hydrogen production and environmental remediation. “We are showing that through photocatalysis, it is possible to produce a renewable fuel while removing organic pollutants, or converting them into useful products.” Stylianou said. 

Glufosinate ammonium and 2,4-dichlorophenoxyacetic acid were two other commonly used herbicides that the team, which also included graduate student Emmanuel Musa, postdoctoral researcher Sumandeep Kaur, and students Trenton Gallagher and Thao Mi Anthony, tested its photocatalyst against.

That worked on water containing them as well – even water with those two compounds plus PMG.

Source: Oregon State University

Leave A Reply

Your email address will not be published.