[twelve40]

if you claim this is sensationalized (ridiculously, too) would you care to decipher what this means:

> They’re operating about 200 ppb at lowest conc. usually we’re looking to remove from a 1 ppb

who does "they're operating" refer to in this sentence?

[anonymouskimmer]

My best guess is that the GP is referring to the concentration of PFOAs in the test setup. It is possible that a technology that is good at reducing higher concentrations of PFOAs is not good at further reducing PFOAs concentration at lower concentrations.

However, from the link to the paper in another comment (note that this is from the introduction; I don't have permission to view the full paper):

> After finding the best operating condition, the effects of solution parameters such as initial pH, DO, temperature, PFOA concentration, and electrolyte concentration in broad ranges were determined. PFOA concentration and sulfate dosage were chosen to be representative of different aqueous environments (e.g., natural waters and brine solutions).

So I'm not sure where GP gets that this 200 PPB number is the case for all of the tests.

[floil]

My interpretation: the paper describes a system that works for a starting concentration of 200 parts per billion, or higher. This is unrealistic because, in real world contamination scenario, you would expect to see a starting concentration of around 1 part per billion.

[greenie_beans]

lol yeah that comment is hard to decipher

[PlasmonOwl]

Sorry fellas I was baked. Yeah basically that's the cricket. If solutions they use are higher than those in the 'real world' it's actually a much bigger challenge than one would think at a first pass. Seeking a 1 ppm solution is a milligram in a litre, this is challenging. 200 ppb (this paper) is impressive, and on the cutting edge. Now, in the real world: 1-2 ppb and below that is where the real challenge lies. It's seeking a needle in a haystack, where your real world solution will contain a million other 'competing' species that will be preferentially bound or decomposed by your agent. The agent could be decomposition agent or a sorbent.