Water Treatment Phosphonates
Organophosphonate scale inhibitors, corrosion inhibitors and chelating agents with high thermal and hydrolytic stability.
HEDP 60
HEDP · Active 58.0 – 62.0 %
CAS 2809-21-4ZEELCHEM™ 111ATMP 50
ATMP · Active ≥ 50.0 %
CAS 6419-19-8ZEELCHEM™ 121PBTC 50
PBTC / PBTCA · Active ≥ 50.0 %
CAS 37971-36-1ZEELCHEM™ 131DTPMP
DTPMP / DTPMPA · Active ≥ 50.0 %
CAS 15827-60-8ZEELCHEM™ 151PAPEMPA
PAPEMP · Active ≥ 40.0 %
CAS 130668-24-5Specification comparison
| Grade | Chemical name | CAS No. | Active / Solids | Appearance |
|---|---|---|---|---|
| ZEELCHEM™ 101 | HEDP 60 % — 1-Hydroxyethylidene-1,1-Diphosphonic Acid | 2809-21-4 | 58.0 – 62.0 % | Colourless to light-yellow transparent liquid |
| ZEELCHEM™ 111 | ATMP 50 % — Amino Trimethylene Phosphonic Acid | 6419-19-8 | ≥ 50.0 % | Colourless to light-yellow transparent liquid |
| ZEELCHEM™ 121 | PBTC 50 % — 2-Phosphonobutane-1,2,4-Tricarboxylic Acid | 37971-36-1 | ≥ 50.0 % | Colourless to light-yellow transparent liquid |
| ZEELCHEM™ 131 | DTPMP — Diethylene Triamine Penta (Methylene Phosphonic Acid) | 15827-60-8 | ≥ 50.0 % | Amber to brown transparent liquid |
| ZEELCHEM™ 151 | PAPEMP — Polyamino Polyether Methylene Phosphonic Acid | 130668-24-5 | ≥ 40.0 % | Light-yellow to amber transparent liquid |
Why phosphonates?
Organophosphonates contain stable C–P bonds, so unlike inorganic polyphosphates they do not hydrolyse to orthophosphate in hot water. They work as:
- Threshold scale inhibitors for CaCO₃, CaSO₄ and BaSO₄ at 1–20 mg/L.
- Corrosion inhibitors, alone or synergised with zinc, molybdate and azoles.
- Chelating agents for Ca, Mg, Fe, Cu and Mn in detergents, textiles, bleaching and metal treatment.
Choosing a phosphonate
HEDP and ATMP are the workhorse carbonate inhibitors. PBTC adds chlorine stability and low phosphorus. DTPMP is the strongest sulphate (barium/strontium) inhibitor. PAPEMP offers the highest calcium tolerance for high-pH, high-cycle water and RO antiscalants.
FAQ
Which phosphonate is best with chlorine biocides?
PBTC (ZEELCHEM™ 121) has the best stability against chlorine and bromine.
Which phosphonate controls barium sulphate scale?
DTPMP (ZEELCHEM™ 131) is the most effective phosphonate for barium, strontium and calcium sulphate scale.
Which phosphonate has the highest calcium tolerance?
PAPEMP (ZEELCHEM™ 151) has exceptional calcium tolerance and suits high-hardness, high-pH water.
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