Electrolysis and Electrochemistry Can Neutralize and Convert Contaminants On-Site: New Technique Addresses Persistent Organic Pollutants (POPs), Including Toxic Pesticides

     Researchers at ETH Zurich, led by Bill Morandi, Professor of Synthetic Organic Chemistry, discovered a way, late last year, to convert some very toxic persistent organic pollutants on-site into other captured chemicals and byproducts. They can do this through electrolysis via alternating current and by utilizing electrochemistry principles.

     Persistent organic pollutants (POPs) are chemically stable and can remain in soil, water, and organisms for decades. These include some very toxic chemicals like the pesticides DDT and lindane. POPs can also accumulate in fatty tissue and enter the food chain. Several of these chemicals were banned long ago, but are still present in the environment and in human blood.

     The new research offers hope that POPs can be remediated successfully.  

"The key advance of this new technology is the use of alternating current to sequester the problematic halogen atoms as innocuous salts such as NaCl (table salt), while still generating valuable hydrocarbons," says Morandi.

     According to ETH Zurich:

“A key distinction between this and previous work is that the carbon skeleton of the pollutants is recycled and made reusable, while the halide component is sequestered as a harmless inorganic salt. “The previous methods were also energetically inefficient,” says Patrick Domke, a doctoral student in Morandi’s group. He explains: “The processes were expensive and still led to outcomes that were harmful to the environment.”

     Phys.org writes:

“Electrolysis enables almost complete dehalogenation of pollutants under mild, environmentally friendly and cost-effective conditions. It cleaves the stable carbon-halogen bonds, leaving behind only harmless salts such as table salt and useful hydrocarbons such as benzene, diphenylethane or cyclododecatriene.”

     These useful hydrocarbons are used in many ways in the chemical industry. Thus, the discovery also enables a circular economy.

"Alternating current protects the electrodes from wear, which is why we can reuse them for many subsequent electrolysis cycles. In addition, the alternating current suppresses unwanted side reactions and the formation of poisonous chlorine gas, allowing the pollutant's halogen atoms to be fully converted to inorganic salts."

“The reactor used by the researchers consists of an undivided electrolysis cell in which dimethyl sulfoxide (DMSO) is used as a solvent—itself a by-product of the pulp process in paper production.”

     The process can directly treat soil and sludge without pretreatment or separation processes. A prototype reactor has been tested successfully on DDT and lindane. It can be assembled on-site. No hazardous substances need to be transported.

     According to the Re Soil Foundation, this new technique could be employed for a variety of POPs as well as other contaminants that are stable in the environment, such as the so-called forever chemicals like PFAS/PFOA. They note EPA’s designation of “persistent” and compare “half-lives” of different stable chemicals:

“According to a study, the half-life of certain fluorinated compounds – i.e., the time it takes for their presence in the environment to be halved after spraying – can reach two and a half years. This is less than the time required for some older pesticides such as DDT, but still 15 times higher than the 60-day limit set by the US Environmental Protection Agency (EPA) for defining a pollutant as ‘persistent’.”

    

 

References:

 

Can electrolysis solve one of the biggest contamination problems? Walter Schmid. Phys.org. November 25, 2025. Can electrolysis solve one of the biggest contamination problems?

Electrolysis can solve one of our biggest contamination problems. Walter Schmid, Corporate Communications. ETH Zurich. November 25, 2025. Electrolysis can solve one of our biggest contamination problems | ETH Zurich

Through electrolysis we can neutralize (and enhance) soil contaminants. Matteo Cavallito. Re Soil Foundation. December 22, 2025. Through electrolysis we can neutralize soil contaminants