merkin
Rising Star
I might have added too much NaOH solution at that step in the "pictorial guide". I added very slowly (dripping funnel) until nothing happened (no clouds/precipitation) similar to doing the FASA drip precipitation stage. It was maybe around 150ml NaOH not 50ml (or even the 20ml mentioned) to that point.
It says to check for pH around 7 after 3 or 4 washes. Now after 10 x 200ml water washes the pH is still around 11.5.
I suspect that maybe I misunderstood that part shouldn't have added until all preciptation stopped (a lá FASA) but rather added just the 20ml and then waited for it to permeate. I am not sure.
My question though:
Do I have to just keep doing this wash/settle (hours)/remove water for however many times or is there a way to short cut this process. For instance could the 'water' be acidified with a bit of vinegar to hasten this or would that screw everything up? It seems like it could take weeks to do the wash/settle/remove!
It says to check for pH around 7 after 3 or 4 washes. Now after 10 x 200ml water washes the pH is still around 11.5.
I suspect that maybe I misunderstood that part shouldn't have added until all preciptation stopped (a lá FASA) but rather added just the 20ml and then waited for it to permeate. I am not sure.
My question though:
Do I have to just keep doing this wash/settle (hours)/remove water for however many times or is there a way to short cut this process. For instance could the 'water' be acidified with a bit of vinegar to hasten this or would that screw everything up? It seems like it could take weeks to do the wash/settle/remove!