LEWATIT® TP 208

Summary

Product identification

Lewatit® TP 208 is a weakly acidic, macroporous cation exchange resin with chelating imino-diacetate groups. It is designed for the selective removal of alkaline earth cations, especially in the presence of alkali ions. The resin has a heterodispersed bead size and a modified polymer structure.

Applications

• Final polishing of brine feed to chlor-alkali membrane cells for the removal of traces of alkaline earth ions (Ca, Mg, Sr, Ba) in the pH-range 8-11, even in the presence of iron(III) ions.
• Removal or recovery of heavy metals from process, wastewater, and potable water streams. The preferential order of removal is: Copper > Vanadium (VO₂⁺) > Uranium (UO₂²⁺) > Lead > Nickel > Zinc > Cadmium > Iron(II) > Beryllium > Manganese > Calcium > Magnesium > Strontium > Barium > Sodium.
• Lewatit® TP 208 does not remove heavy metals from solutions containing EDTA or NTA.
• Cadmium is removed from solutions containing cyanides.

Operating characteristics

• The operating capacity is dependent on the pH of the brine; it is approximately threefold at pH 10 compared to pH 7.
• At pH 10 and 5 ppm calcium content, an operating capacity of approximately 12 g Ca/l (of resin in di-sodium-form) is obtained.
• At a service flow rate of 20-30 BV/h, residual calcium concentration is typically below 20 ppb.

Conditioning

• Lewatit® TP 208 must be conditioned with caustic soda solution (NaOH) after every regeneration cycle and before every exhaustion cycle.
• After conditioning, it is in the di-sodium-form and ready for use.

Physical and Chemical Properties

• Ionic form as shipped: Na⁺
• Functional group: iminodiacetic acid
• Matrix: crosslinked polystyrene
• Structure: macroporous
• Appearance: beige, opaque
• Total capacity (H-Form): min. 2.9 eq/l
• Uniformity Coefficient: max. 1.8
• Bead size (> 90 %): 0.4 - 1.25 mm
• Effective size: 0.55 (+/- 0.05) mm
• Bulk density (+/- 5 %): 740 g/l
• Density (approx.): 1.17 g/ml
• Water retention: 55 - 60 wt. %
• Volume change (Na⁺ --> H⁺): max. -35 vol. %
• Stability (pH-range): 0 - 14
• Storability (max. years): 2
• Storability temperature range: -20 - +40 °C

Recommended Operating Conditions

• Operating temperature (max.): 80 °C
• Operating pH-range: 2 - 12
• Bed depth (min.): 1000 mm
• Specific pressure drop (15 °C): approx. 1.1 kPa*h/m²
• Pressure drop (max.): 250 kPa
• Linear velocity (operation, max.): 40 m/h
• Linear velocity (backwash, 20 °C, approx.): 10 m/h
• Bed expansion (20 °C, per m/h, approx.): 4 vol. %
• Freeboard (backwash, vol. %): 80 (extern / intern)

Regeneration (HCl)

• Co-current regeneration level (approx.): 140 g/l
• Co-current regeneration concentration (approx.): 4 - 10 wt. %
• Linear velocity (regeneration, approx.): 5 m/h
• Linear velocity (rinsing, approx.): 5 m/h

Conditioning (NaOH)

• Conditioning level: 40-48 g/l (Mono-Na), 80-96 g/l (Di-Na)
• Conditioning concentration (approx.): 4 wt. %
• Linear velocity (conditioning, approx.): 5 m/h
• Rinse water requirement (slow / fast, approx.): 5 BV

Additional Information

• Safety precautions: Avoid contact with strong oxidants like nitric acid. Observe the safety data sheet.
• Disposal: Follow European waste nomenclature within the European Community.
• Storage: Store above freezing point, dry, out of direct sunlight. If frozen, thaw gradually at ambient temperature before handling or use.

Disclaimer: Extraction may miss figures, footnotes, or revisions; contractual data must match the OEM PDF revision used on the project.

Official datasheet (PDF)

Lenntech datasheet mirror