Lewatit® MDS TP 208 is a weakly acidic, macroporous cation exchange resin with chelating iminodiacetic
acid groups. It has been designed for selectively binding transition and alkaline earth metal cations. Its
monodisperse beads are of high mechanical and osmotic stability.
Lewatit ® MDS TP 208 is a small bead variant of Lewatit ® MonoPlus TP 208 with excellent kinetic
performance. It gives 50 to 80 % higher operating capacities without requiring additional regenerant
chemicals.
Due to the smaller bead sizing Lewatit® MDS TP 208 delivers higher pressure drops across resin beds.
Pump designs need to adjusted accordingly. A higher sensitivity towards plugging by suspended particles
requires suitable prefiltration of the feed stream e.g. by use of sandfilters or filter candles.
Divalent cations are removed from neutralized waters in the following order: Copper > Vanadium (VO2+) >
Uranium (UO22+) > Lead > Nickel > Zinc > Cadmium > Iron (II) > Beryllium > Manganese > Calcium >
Magnesium > Strontium > Barium >>> Sodium.
Adsorption of trivalent cations also takes place. For instance iron (III) can be adsorbed and can — in
contrast to Lewatit® MonoPlus TP 260 and related products - also be desorbed with acid.
It is especially suitable for use in:
» the secondary purification of brine feed to chloralkali membrane cells (traces of alkaline earth ions are
removed after their normal precipitation by carbonates in the pH-range 7-11)
» the secondary purification of brine especially where removal of Sr and Ba is required
» the purification of waste water
» the recovery of valuable metals
In brine purification, the operating capacity of Lewatit® MDS TP 208 is pH-sensitive. At pH 10 it is approx.
three times that achieved at pH 8. At pH 10 and a calcium content of 5 ppm, capacities up to 20 g Ca per
liter of Lewatit® MDS TP 208 (relative to the volume of the di-sodium-form) are obtained. At a service flow
rate of 20-30 BV/h, the residual calcium values are well below 10 ppb. Stable plant performance is best
achieved by operating two units of equal size in series.
Lewatit® MDS TP 208 has to be conditioned with caustic soda solution after every regeneration cycle and
before every exhaustion cycle. After the conditioning it is in the di-sodium-form and can be used for the next
cycle in the final polishing of chloralkali brine feed.
The special properties of this product can only be fully utilized if the technology and process used
correspond to the current state-of-the-art. Further advice in this matter can be obtained from Lanxess,
Business Unit Liquid Purification Technologies (LPT).
This document contains important information
and must be read in its entirety.
Edition: 2014-01-16
Previous Edition: 2014-01-13
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General Description
Ionic form as shipped
Functional group
Matrix
Structure
Appearance
Na+
Iminodiacetic acid
Crosslinked polystyrene
Macroporous
Beige, opaque
Specified Data
Total capacity
Uniformity Coefficient
Mean bead size
metric units
min. eq/l
max.
mm
H-Form
2.8
1.1
0.39 (+/- 0.03)
Physical and Chemical Properties
Bulk density
Density
Water retention
Volume change
Stability
Storability
Storability
metric units
g/l
approx. g/ml
wt. %
max. vol. %
(+/- 5 %)
Na+ --> H+
at pH-range
of the product
temperature range
max. years
°C
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740
1.16
59 - 65
- 35
0 - 14
2
-20 - +40
Recommended Operating Conditions*
metric units
OPERATION
Operating temperature
Operating pH-range
Bed depth
Specific pressure drop
Pressure drop
Linear velocity
Specific flow rate
OTHER PARAMETERS
REGENERATION, COCURRENT
Regenerant
Regenerant
Regenerant
Linear velocity
Linear velocity
Linear velocity
Rinse water requirement
Bed expansion
Bed expansion
Freeboard
CONDITIONING
Conditioning agent
Conditioning agent
Conditioning agent
Linear velocity
Linear velocity
Volumetric flow rate
max. °C
min. mm
approx. kPa*h/m2
max. kPa
max. m/h
max. BV/h
(15 °C)
operation
exhaustion
type
quantity
concentration
approx. g/l
approx. wt. %
approx. m/h
approx. m/h
approx. m/h
approx. BV
approx. % per m/h
approx. vol. %
vol. %
backwash (20 °C)
rinsing
slow / fast
backwash (20 °C)
(20 °C, per m/h)
backwash
type
quantity
concentration
rinsing
conditioning
regeneration
g/l
approx. wt. %
approx. m/h
approx. m/h
BV/h
This document contains important information
and must be read in its entirety.
Edition: 2014-01-16
Previous Edition: 2014-01-13
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80
2 - 12
ca. 1000
3
250
30
5 - 25
HCl
150
4 - 10
5
4
5
5
12
100 (Na)
NaOH
80 - 88
4
5
5
2
Additional Information & Regulations
Safety precautions
Strong oxidants, e.g. nitric acid, can cause violent reactions if they come into contact with ion exchange
resins.
Toxicity
The safety data sheet must be observed. It contains additional data on product description, transport,
storage, handling, safety and ecology.
Disposal
In the European Community Ion exchange resins have to be disposed, according to the European waste
nomenclature which can be accessed on the internet-site of the European Union.
Storage
It is recommended to store ion exchange resins at temperatures above the freezing point of water under
roof in dry conditions without exposure to direct sunlight. If resin should become frozen, it should not be
mechanically handled and left to thaw out gradually at ambient temperature. It must be completely thawed
before handling or use. No attempt should be made to accelerate the thawing process.
This information and our technical advice – whether verbal, in writing or by way of trials –
are given in good faith but without warranty, and this also applies where proprietary rights
of third parties are involved. Our advice does not release you from the obligation to check
its validity and to test our products as to their suitability for the intended processes and
uses. The application, use and processing of our products and the products manufactured
by you on the basis of our technical advice are beyond our control and, therefore, entirely
your own responsibility. Our products are sold in accordance with the current version of
our General Conditions of Sale and Delivery.
This document contains important information
and must be read in its entirety.
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Previous Edition: 2014-01-13
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Lenntech
info@lenntech.com Tel. +31-152-610-900
www.lenntech.com Fax. +31-152-616-289