This looks very promising! Efficiently dehalogenizing toxins, preserving their carbon "skeletons" to be repurposed for valuable (nontoxic) industrial chemicals, creating NaCl (table salt) as a byproduct... seems full of win to me. Here's hoping...
Benzene is quite toxic. The EPA classifies benzene as a known human carcinogen for all routes of exposure. And their method leaves it buried it in the soil. It is not a valuable industrial chemical when it is in the soil, it is a pollutant.
Benzene is toxic, but it still has industrial uses. From the article:
> The reactor used by the researchers consists of an undivided electrolysis cell in which dimethyl sulfoxide (DMSO) is used as a solvent
They remove the DDT from the soil into the solvent (itself quite unpleasant). From there, it's pretty easy to filter out the soil and clean it up. Add water and boil or freeze dry to extract it back out, preferably capturing it to be reused.
> From there, it's pretty easy to filter out the soil and clean it up.
"Cleaning" soil is an interesting concept. At what point does it just become dirt? Presumably some of the nutrients will remain, but it seems like this would sterilize it.
Dirt still has use, of course, but soil is expensive to produce for a reason.
I don't think anyone is really too concerned about DDT harming the soil itself.
DDT, like organic mercury compounds, bioaccumulates up the food chain. Contaminated soil is sequestered to prevent it from contaminating insects and animals and then humans.
Hence, the trade-off: DDT in the ecosystem, or killing soil and rebuilding it with compost and time.
This all sounds like it would be many manyfold more expensive than just digging it all up, gathering it all togheter and putting it into some quarry or so that doesn't let much if any seepage happen.
I don't think it is intended to be commercially viable on the basis of benzene production alone.
Rather, it is a more permanent solution compared to sequestration, where the benzene production offsets the cost.
If, as they plan, it can be done on-site, that would also eliminate transporting the soil and avoiding accidentally spreading it elsewhere, which is appealing as well.
Sanitary landfills (the sort that prevent seepage) are not exactly cheap either, and pose an ongoing risk in that the DDT is always there, waiting to get back out.
