Rapid formation of iminodiacetate from photochemical degradation of iron(III) nitrilotriacetate solutions

Abstract

Gas chromatography has been used to monitor the rapid photodegradation which dilute solutions of Fe(III)-nitrilotriacetate undergo when exposed to sunlight. Iminodiacetate is produced in essentially stoichiometric amounts and is only very slowly photodegraded to glycine under the same conditions. The resulting accumulation of iminodiacetate in natural water systems with continuing input of nitrilotriacetate, which these observations suggest, is of environmental concern because of the possible carcinogenic activity of Nnitroso iminodiacetic acid.

Phototrophic Fe(II) Oxidation Promotes Organic Carbon Acquisition by Rhodobacter capsulatus SB1003

“…We propose that coupling the Fe(II) oxidation activity of R. capsulatus SB1003 with Fe(III)-NTA photochemistry degrades recalcitrant NTA into a labile carbon source, analogous to what occurs for Fe(III)-citrate. Fe(III)-NTA photochemistry is well documented in the literature, and the expected products are Fe(II), iminodiacetate, formaldehyde, and CO 2 (37,40). Based on the presence of a gene annotated as a glutathione-dependent formaldehyde dehydrogenase (RRC01948) in the sequenced genome of R. capsulatus SB1003, we predict that the growth on Fe(II)-NTA occurs as a result of Fe(II) oxidation and Fe(III)-NTA photochemistry leading to the production of formaldehyde.…”

Chelating agents in high temperature aqueous chemistry. 2. The thermal decomposition of some transition metal complexes of nitrilotriacetate (NTA)

“…The stability constant of C u 1 ' 1~A 0 is much smaller than that of Cu1'NTA-(by a factcr of at least 200, at 298 K (24)). so that the I D A formed by oxidation of NTA not only cannot compete effectively with the remaining NTA for coordination to copper (11) but is also less conducive than IVTA to reaction 4 even when coordinated. Consequently.…”

“…By contrast, photochemical degradation of FeH1NTA or biodegradation of the free ligand should. when available, consume NTA pollutants in a matter of weeks (5)(6)(7)(8)(9)(10)(11)(12)(13)(14).…”

“…lroll (l'l?. cobalt(ll) (10,11) has been shown to proceed by deacetylation (loss of -CH, COO-) rather than by decarboxylation (loss of CO,). and the photochemical degradations of c u H N T A -(12) and FeT"-EDTA- (1 3, 14) have also been examined.…”

“…This colnplex decomposed readily above 530 K with reduction of iron(1II) to iro11 (11), yielding the solid FeH,(NTA),.H,O (see below) a t 530 K, and magnetite at higher temperatures. The rate of reaction was tlie sanie whether the starting material was FeT"NTA,H,O or an equiinolar mixture of FeCI, \vith Na,NTA, i.e., it was unaffected by the presence of Na' or CI-.…”