Interesting development in desalination

[grae]

seems that some science bods over at Columbia have discovered a cheap and easy way to desalinate water, not sure whether that will ever translate into a method for offshore water making but definitely worth watching

https://science.slashdot.org/story/1...alt-from-water

Grae Morrison
'72 Cal 2-29 Destiny
Red Bank, NJ

[GordMay]

“Membrane-less and Non-Evaporative Desalination of Hypersaline Brines by Temperature Swing Solvent Extraction” ~ by Chanhee Boo et al.
➥ https://pubs.acs.org/doi/10.1021/acs.estlett.9b00182

More ➥ https://engineering.columbia.edu/pre...l-desalination

[Franziska]

Interesting.

Not sure I understood that right, but do we than need to stock that solvent onboard?
What do you do with solvent and brine?
Is that biodegradable and environmentally ok to dispose?

[zboss]

Originally Posted by Franziska

Interesting.

Not sure I understood that right, but do we than need to stock that solvent onboard?
What do you do with solvent and brine?
Is that biodegradable and environmentally ok to dispose?

Distilled water is a solvent so until we know what that solvent is (I didn’t read the extended article) we can’t assume it’s not eco friendly.

[GordMay]

Originally Posted by zboss

Distilled water is a solvent so until we know what that solvent is (I didn’t read the extended article) we can’t assume it’s not eco friendly.

Among the solvents, DIPA exhibited the highest water extraction efficiency whereas ECHA and DMCHA produced water with the lowest salt content and solvent residue content, respectively.
DIPA = diisopropylamine
ECHA = N-ethylcyclohexylamine
DMCHA = N,N-dimethylcyclohexylamine

[Franziska]

Hey Gord, thanks for that.
Any thoughts on the environmentally friendliness of these?
I did not understand the article fully and have the impression that the saturated brine needs to be dumped or reprocessed in special facilities.

[GordMay]

DIISOPROPYLAMINE (DIPA) Hazard Sheet:
“... It may be necessary to contain and dispose of Diisopropylamine as a HAZARDOUS WASTE. Contact your state Department of Environmental Protection (DEP) or your regional office of the federal Environmental Protection Agency (EPA) for specific recommendations. * If employees are required to clean-up spills, they must be properly trained and equipped. OSHA 1910.120(q) may be applicable ...:
☞ https://nj.gov/health/eoh/rtkweb/documents/fs/0728.pdf

[Franziska]

So, not really something we would like in larger quantities on board.
Guess reverse-osmosis is with us for a while. Still, a while ago there was also rumors or a Graphene based filters which can do it without the high pressure.
Heard nothing new on this though more recently.

[trifan]

Originally Posted by Franziska

So, not really something we would like in larger quantities on board.
Guess reverse-osmosis is with us for a while. Still, a while ago there was also rumors or a Graphene based filters which can do it without the high pressure.
Heard nothing new on this though more recently.

A big corp (can't remember which - 3M, whatever) bought up the patent rights for graphene filter tech. Good luck seeing an affordable unit any time soon.

[Davidhoy]

Interesting that the article specifically mentions "Hypersaline brines—water that contains high concentrations of dissolved salts and whose saline levels are higher than ocean water". The article further talks about this desalination as a way to clean up toxic "water produced during oil and gas production, inland desalination concentrate, landfill leachate (a major problem for municipal solid waste landfills), flue gas desulfurization in fossil-fuel power plants, and effluent from industrial processes". Not sure that this is a viable alternative for the typical cruising sailor, but it is still interesting nevertheless.

-David.

[DMCantor]

This is aimed at brines that have on the order of 5-10x the salinity of sea water. It makes little sense for cruisers, but could be very useful in dealing with brines that are a byproduct of oil production, for example. Even trace amounts of these solvents remaining in the water would make them unfit for human consumption. This kind of technology could make sense if you need to desalinate tens of thousands of gallons of highly concentrated brines.

[Grattaway]

Lots of work still being done with graphene - it should prove to be the filter of the future but may also be the material boats are built out of - or painted with to reduce fouling