Water Absorbers (Dessicants)
•
Silica gel
•
Silicon dioxide
–
pure, porous, amorphous
–
chemically inert, non-
toxic, resists attrition
•
high capacity > 40% RH
•
low capacity < 40% RH
•
fair capacity > 32
o
C
•
impregnation with
CoCl
2
: colour change
•
most common
•
Activated
clay
•
Mined and processed
–
variation in properties
•
Oxide of silicon,
aluminium, iron and
magnesium
•
fair absorption capacity
at low RH
•
poor capacity >32
o
C
•
inexpensive
•
specific applications