ZIP WATER PURIFIER USER GUIDE
WHAT IS NATURAL OSMOSIS AND REVERSE OSMOSIS?
Natural or direct osmosis is common in nature; found in places like the semi
-
permeable membranes
which are part of the vast majority of organisms (e.g. plant roots, our own body organs, cell membranes)
When two solutions of different concentrations of salts (TDS
-
Total dissolved solids) are separated by a
semi permeable membrane, it naturally produces a flow of water from the less concentrated solution to
the higher concentrated solution. This flow continues until the concentrations on both sides of the mem-
brane are equal.
To overcome this tendency, and reverse the natural flow of the system, (in order to obtain a flow of water
from a higher salt concentration solution to a lower salt concentration solution) pressure is applied to the
water on the side of the membrane with the higher concentration. Pure water is collected from the lower
pressure side of the membrane and this process is what is called reverse osmosis. Today, reverse osmo-
sis is one of the best methods for improving the characteristics of water by a physical process without
using chemicals.
HOW DOES THE MEMBRANE WORK?
Pressure is applied to the water on the inlet side of the semi permeable membrane, so that part of it (RO
water) will flow through the pores of the membrane, while the rest of the water (water rejected with high
salt concentration) will be diverted back to the supply pitcher to recycle and optimise performance.
Since the diameter of the pores of the membrane is less than 0.0001 microns, only water molecules and
a small amount of minerals (sodium, potassium, calcium, magnesium, etc.) will pass through the mem-
brane. Larger molecules will be
“
rejected
”
from passing through the membrane.
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