Print PDF
Favorite
Email
Step 10Second filtering to remove (most) remaining carbon particles
From this step forward, cleanliness will be of utmost importance to avoid getting dust or other contaminants into the solution you're working so hard to filter.
First, heat up the solution. It doesn't have to be boiling, but a hot solution will give a higher flow rate through the filter. While it's heating, wash out the empty container you're going to use to receive the filtered solution; if it's the one you poured the solution out of in the previous step, don't just rinse it - wash it with a little soap and a cloth or rag, to make sure all carbon particles are removed. When you finish rinsing it out, do not dry it with a towel or anything else! Shake it out, but leave it wet.
This filtering step will use six coffee filters at a time. If you're lucky enough to have a lab stand with clamps, you can use it to hold a funnel over your receiving container as shown in the picture (get 'em cheap at American Science & Surplus). If not, no worries - you can use your strainer instead. If you use the strainer, just be certain to wash it carefully beforehand (again, wash - not just rinse), so that no carbon particles remain that could contaminate the filtered solution.
Place six filters, nested together, into your clean strainer and set it in position on your receiving
container; or, if you're using a funnel, fold the stack of filters the way you were taught in science class - flatten them into a circle (all together, not individually), fold the circle in half, fold that in half again, and open one "pocket", forming the folded filters into a conical shape that fits into the funnel.
Using a one cup measuring cup (or similar small container with an appropriate lip for pouring), fill the filter with hot solution and let it drain. Keep transferring hot solution into the filter until all solution has been filtered. If flow through the filter slows down too much, you can replace the filters. Be careful not to overfill the filter.
While you're waiting for the solution to filter, blanch one head of cabbage... (oh wait, nevermind, that was for dinner...)
First, heat up the solution. It doesn't have to be boiling, but a hot solution will give a higher flow rate through the filter. While it's heating, wash out the empty container you're going to use to receive the filtered solution; if it's the one you poured the solution out of in the previous step, don't just rinse it - wash it with a little soap and a cloth or rag, to make sure all carbon particles are removed. When you finish rinsing it out, do not dry it with a towel or anything else! Shake it out, but leave it wet.
This filtering step will use six coffee filters at a time. If you're lucky enough to have a lab stand with clamps, you can use it to hold a funnel over your receiving container as shown in the picture (get 'em cheap at American Science & Surplus). If not, no worries - you can use your strainer instead. If you use the strainer, just be certain to wash it carefully beforehand (again, wash - not just rinse), so that no carbon particles remain that could contaminate the filtered solution.
Place six filters, nested together, into your clean strainer and set it in position on your receiving
container; or, if you're using a funnel, fold the stack of filters the way you were taught in science class - flatten them into a circle (all together, not individually), fold the circle in half, fold that in half again, and open one "pocket", forming the folded filters into a conical shape that fits into the funnel.
Using a one cup measuring cup (or similar small container with an appropriate lip for pouring), fill the filter with hot solution and let it drain. Keep transferring hot solution into the filter until all solution has been filtered. If flow through the filter slows down too much, you can replace the filters. Be careful not to overfill the filter.
While you're waiting for the solution to filter, blanch one head of cabbage... (oh wait, nevermind, that was for dinner...)
| « Previous Step | Download PDFView All Steps | Next Step » |
1
comment
|
Add Comment
|
Sep 11, 2009. 2:38 PM
GentleMiant
says:
GentleMiant
says:
Not going to use the cabbage? Ahhh, you really don't NEED an indicator, do you? But about the washing of the container, after that I always rinse with distilled water. I NEVER trust tap water to be "pure".
Reply
1
Oct 5, 2009. 10:44 AMindigoandblack (author)
says:
Agreed, though in this case it really shouldn't make a whole lot of difference. I wouldn't use tap water if I had to add water to the solution ever, but tap for washing ought not change anything.
Reply
Oct 6, 2009. 3:00 PMGentleMiant
says:
GentleMiant
says:
Ok. But small impurities CAN make a big difference. Even in crystallization. A few decades ago an electronics co. (maybe GE or Motorola) had difficulty with their supply of quartz for making frequency standards. They came up with an organo-compound crystal that worked just as well... until it started growing in another "habit". They tried to isolate the process from whatever the "impurity" was causing the problem. Even using a facility in another state! Nothing worked. Fortunately the problem with the quartz supply got solved.
Reply
 |
Add Comment
|
