Activated charcoal can not be used to form glacial acetic acid--just to remove impurities in the GAA (similar to how you remove fusel oils from EtOH with activated charcoal and 50% EtOH). Actually, acetic acid is preferentially is adsorbed onto activated charcoal (i.e. preferential to the water).
From what I understand, you absolutely need to do azeotropic distillation with an column containing a large number of theoretical plates to concentrate dilute acid... here is the phase diagram data for water/AcOH from Perry's (to the right is w/w %'s I calculated from the mol frac data):
mol frac w/w
Temp liquid vapour liquid vapour
118.3 0 0 100 100
110.6 0.1881 0.3063 93.5 88.3
107.8 0.3084 0.4467 88.2 80.5
105.2 0.4498 0.5973 80.3 69.2
104.3 0.5195 0.658 75.5 63.4
103.5 0.5824 0.7112 70.5 57.5
102.8 0.675 0.7797 61.6 48.5
102.1 0.7261 0.8239 55.7 41.6
101.5 0.7951 0.8671 46.2 33.8
100.8 0.8556 0.9042 36.0 26.1
100.8 0.8787 0.9186 31.5 22.8
100.5 0.9134 0.9409 24.0 17.3
100.2 0.9578 0.9708 12.8 9.1
100 1 1 0 0
If you take the time, and plot it, you'll quickly see why you can't just do a simple distillation to sufficiently purify the acid.
If you use a very long column with a good packing and with a high reflux ratio (ie nixon-stone type reflux head), then... yeah, you could go from 80% to nearly 100% without doing an azeotropic distillation. Do you guys have this sort of equipment? likely not... if you did, you wouldn't be asking this question.
A simple nixon-stone type arrangement can be made using a 24/40 RB flask attached to a very long 24/40 tube (male/female ends) that works as your column (filled with inert packing material), then a dean stark adapter (with stopcock), then a claisen adapter to monitor the temperature, then a reflux condenser ontop of that...) Set it to a healthy boil, so that the reflux rate thru the column is fairly regular, then only open the stop cock a bit to collect a rate of distillate considerably less than the rate of reflux.
Let us know how it goes... I'd love to find a better way. I've got a ton of this diluted acetic acid myself.