An important group indegradable substances containing both phosphor and nitrogen are the phosphonic acids and their derived phosphonate salts. All phosphonic acids contain several O=P-OH groups per phosphonic acid molecule. Most phosphonic acids also contain organic nitrogen groups =N=(CH2)3. Phosphonic acids are dangerously etching and corrosive substances. This is why often the derived salts with O=P-Na+ groups are used instead. These however contain the same amount of phosphor and nitrogen as the original phosphonic acid.
In water treatment and detergency, phosphonic acids are useful ingredients; they keep metal ions in solution and they avoid scales from growing further. This way they keep hard water soft and avoid sediments like scaling and rust. Phosphonic acids have such an excellent ‘sequestring’ functionality that they sweep clean any soft (textile) or hard (floors, tables, steel, natural stone, etc) surfaces, removing metal salts and subsequently surrounding them, decreasing redispositioning to neglectable levels. Because these are large, heavily negatively charged molecules which, from their basic functionality, form complexes with metal ions, bacteria cannot break down these phosphonic acids and phosphonates. They would like to; phosphor and nitrogen are feedstocks formost bacteria, transforming them into phosphates and nitrites. Which are harmful again…
Behold a typical environmental dilemma; industrial phosphonic acids/phosphonates are indegradable and thus accumulate in the environment. But if we would develop better degradable phosphonic acids/phosphonates, harmful phosphates and nitrites would end up in the environment. How to solve such a dilemma? Parties with little chemical competence press for a total ban on phosphonic acids. But there are intelligent alternatives; phosphor- and nitrogen free sequestring agents with proven functionality.
PESA acid HO(C4H4O5)nH or the derived salt HO(C4H2O5Na)nH is a polymer with a molecularweight of 400 – 1500 and carbonic acid groups O=C=OH instead of phsophonic acid groups. There is no phosphor and no nitrogen in PESA. In the long carbon chains an oxygen atom is builtin after every 2 C-atoms (poly epoxy). These are points of attack for bacteria. This causes the PESA molecules to fall apart in their monomers (building blocks) for over 60% within 28 days. In the language of safety data sheets this is called ‘readily biodegradable’. And not a single phosphor- or nitrogen atom is released in the process. The testmethods measuring this are mentioned at the end of this newsletter.
Just like phosphonic acid and phosphonates PESA avoids precipitation of scale, calcium sulfate, calcium fluoride and silicates. The PESA salt functions well at high pH; the PESA acid at low pH. They are stable, even when aggressive chlorines are present.
PASP acid C4H6NO3(C4H5NO3)nC4H6NO4 or the derived salt C4H6NO3(C4H4NO3Na)nC4H6NO4 is a polymer with a molecular weight of 1000 – 5000, also with carbonic acid groups instead of phosphonic acid. So there is no phosphor but there is nitrogen present in PASP. Some customers measure that PASP thus avoids better barium sulfate and calcium phosphate precipitates and has an improved anti corrosive functionality. On top of the already mentioned advantages of PESA.
The Sirius Effect
PESA and PASP were developed by the same manufacturer supplying the phosphonic acids and phosphoniates. So they know what they talk about and can compare PESA and PASP with traditional phosphonic acids one on one.
You can obtain PESA and PASP from us in solid and in 40% dissolved form (1.2 g/ml with pH1% 9-11). The readily biodegradations of our PESA and PASP were measured with following international methods:
These are the norms also maintained by Ecolabel and Nordic Swan.
PESA and PASP are such green products that they belong on every laboratory shelf.
In 2013 you will choose for green innovation!
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