| 1. Strength of ion exchange resins |
| . |
P.R China pays very much attention
to Strength resins. She has formulated the quality index and the corresponding
determination methods. They are different from those of other countries.
|
| . |
For gel-type resins, the quality index of strength is:
|
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M(Attrited spherical ratio)
>= 90% |
| . |
For macroporous type resins, the quality index is: |
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S(Osmotic-Attrited spherical
ratio) >= 90% |
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| The determination methods of M and S are as below: |
| |
(1) Determination methods of M |
| . |
Add 50 ml ion exchange resin
sample (as received), 150ml deionized water, and 10 China spheres
of 10g in weight and 20 mm in diameter into a stainless steel cylinder
of 125 mm in which can rotate the cylinder at 125 r/min. For cation
resins, ler the cylinder rotate for 15 min, and for anion resins,
30 min. Filter the resin with a net of more than 200 mesh and put
it into a oven at 60℃ for 2-3h, until the resins can roll freely.
Because the spherical resin particles can roll down from the upper
part of a inclined smooth glass plane while the broken ones can't,
the whole sphere particles and borken particles can be separated.
The weight percentage of the whole sphere particles is just M (the
Attrited spherical ratio.) |
| |
|
| . |
(2) Determination methods of S
|
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Add 16ml resin sample (as received)
into a PMMA column of 20 mm in internal diameter. Oper the valve of
the column and drain the water away. Pour 25 ml 1N HCl (for Na-type
cation resins, OH-type or free-amino anion resins) or IN NaOH (for
H-type cation resins, Cl-type anion resins) into the column, and drain
it away in 10-15 seconds. Repeat this operation 5 times. Close the
valve, pour 20 ml the same solutin into the column and remove the
bubbles in it, then rinse the resin with 250 ml the same solution
in 10 min. Close the valve, pour 25 ml deionized water into the column,
remove the bubbles in it, rinse the resin again with 250 ml deionized
water in 5 min. |
| . |
Then, treat the resin by the
same method with another solution (lN NaOH for Na-type cation resins,
OH-type or free-amino anion resins; lN HCl for H-type cation resins
or Cl-type anion resins ) and deionized water. |
| . |
Add 15ml resin treated above,
50 ml deionized water and China spheres(6 for cation resins and 10
for anion resins) into the stainless steel cylinder and let it rotate
(10 min for cation resins and 20 min for anion resins). After that,
separate the whole sphere particles from the broken ones. The weight
percentage of the whole sphere particles is just S (the Osmotic-Attrited
spherical ratio). |
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| 2.Particle sizes of the resins |
| . |
For general type resins, particle
sizes are normally 0.4-1.25mm, uniformity coefficient are normally
1.6 max. We can also supply resins with various particle size ranges,
effective diameters and uniformity coefficients according to the requirement
of customers. |
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| 3.Applications of the resins |
| . |
The resins listed above are mainly used
in industrial water treatment and as catalysts for organic reactions.
We can also supply resins suitable to Food and Pharmaceutical Industry,
resins suitable to treatment of domestic waste water, etc. |
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| 4.Store of the resins |
| . |
Ion exchange and adsorbent resins some water.
The water is necessary to keep the function of the resins. If ion
exchange resins retain lose their water partly during store or transportation,
they should be immersed first into 10% NaCl solution for 1-2h and
then washed with water slowly. Adsorbent resins should be immersed
first into polar organic solvents (such as MeOH, EtOH or Acetone)
for 1-2h, and then washed with water in this case. |
| . |
The temperature of stone and transportation
should be 5-40℃. If the ambient temperature is too low, the resin
should also be immersed into NaCl solution to prevent the water from
freezing. |
