Quote:
Originally Posted by Jacques Reed
"Chelating" needs to be researched further.
|
Hi Jacques,
You may have to wade through quite a few scholarly articles to find anything relevant to molasses. Try search terms like "biological rust removal" or "siderophores in rust removal". Also think about possible industry use, eg. environmental applications such as cleanup of contaminated sites (heavy metals) or perhaps sewage treatment. Quick search turned up a few mentions here:
http://www.envismadrasuniv.org/nl200...sidephore.html
"Sidephores in rust removal: Bacteria, fungi and plants are using biological chelating compounds in order to efficiently bind iron ions. So rust layers can be abated in a natural and gentle way. Biologists, mineralogists and biotechnology engineers have been investigating the process of biological rust removal for many years."
Who knew!!
"Iron is an important element for all living cells. It is difficult to take up iron into cells due to its poor solubility. For the iron supply of living cells, some microorganisms including bacteria, fungi, actinomycetes and algae produce an iron chelator, siderophore, outside the cells and the siderophore is chelated with ferric iron. The role of these compounds is to scavenge iron from the environment and to make the mineral, which is almost always essential, available to the microbial cell."
"Research in this field begun about six decades ago, and interest in it accrued with the realization that most aerobic and facultative anaerobic microorganism synthesize at least one siderophore. In addition, they have applications in clinical, agricultural and environmental fields. At present nearly 500 siderophores are reported from selected microorganisms."
"Currently the applications of siderophores in clinical, agricultural and environmental sector are reported in some extent. But the siderophore research is not at all initiated in most of the microbiology research laboratories. So, there is a need to discover siderophores from normal and also extremophiles in the ecosystems like deep sea, desert and forest to exploit their applications for welfare of all living beings as well as for environment, particularly cleanup of heavily rusted CMP vehicle parts."
OK, so I added that last bit.
Point being that if we can identify the most suitable bugs we can selectively grow them in our molasses bath. That means providing the ideal growth medium (dilution rate, temperature, pH, additional nutrients, oxygenation) and introducing the chosen species in large numbers, preferably in active form, so it can rapidly multiply. In other words, just like home brewing or wine making, where you select the desired yeast strain and pitch it in quantity into your wort (beer) or must (wine). In this way the lag time is reduced dramatically, from several weeks to several hours, and the desired species predominates. Of course, in this case we're trying to produce siderophores, and since the strongest known siderophore is Enterobactin, which is produced by E.coli, I shall leave it to your imagination how best to introduce active E.coli in quantity into your molasses bath!
On the question of alternatives it must first be noted: "Chemically siderophores are iron binding proteins with molecular weight ranging from 400 - 1500 Da." Key word: PROTEINS.
Alternative chelating agents are ORGANIC ACIDS: citric acid, acetic acid, EDTA (Ethylene-Diamine-Tetra-Acetic acid). These bind a range of metal ions, and in addition to household use for removal of scale (calcium, lime, rust) they find extensive use throughout industry in a wide range of applications. These can be researched quite readily, eg:
http://www.glossary.oilfield.slb.com...ing_agent.aspx
"Chelating agents associate with iron [Fe+3 or Fe+2] to form soluble complexes. Citric acid, acetic acid and EDTA are effective chelating agents and can be used at temperatures up to 400oF [204oC]."
This suggests they may find use in hot tanks as an alternative to caustic soda, perhaps for non-ferrous metals like the pot metal you mention Jacques. Also if it works rapidly on rust it may be useful for small parts when you need them in a hurry. Just boil them up in a saucepan on the stove! Also worth investigating are inhibitors added to prevent flash rusting.
I notice Matt has trialled citric acid and acetic acid (in vinegar) with good results it would seem. I bought some EDTA on ebay which I'll be interested to trial as well:
http://www.ebay.com.au/itm/EDTA-4Na-...UAAOSwZd1VW2YO
Something else I'd like to investigate for small parts is Immersible Ultrasonic Transducers.
Cheers,
Tony