Speciation 98: Abstracts

Because of the non-readily biodegradation of EDTA as its undisputed usage, other replacement ligands are being sought. Therefore, the chemical speciation of exceedingly large and complex equilibrium systems is being researched using computer modelling based upon sophisticated software such as JESS (Murray and May, 1991, 1993, 1996) for a series of biodegradable ligands, N-methyliminodiacetate (MIDA^2-), L-2-(Carboxymethyl)iminodiacetate (CIDA^3-), Iminodisuccinate (IDSA^4-), and N-carboxymethyliminodisuccinate(MAIDSA^5-).

Formation constants for H⁺, Ba²⁺, Sr²⁺, Mg²⁺, Ca²⁺, Mn²⁺, Fe²⁺, Cd²⁺, Co²⁺, Zn²⁺, Pb²⁺, Ni²⁺, La³⁺, Pr³⁺, Nd³⁺, Sm³⁺, Gd³⁺, Eu³⁺, Y³⁺, Tb³⁺, Dy³⁺, Ho³⁺, Er³⁺, Tm³⁺, Yb³⁺, and Lu³⁺ with MIDA^2-, CIDA^3-, IDSA^4-, and MAIDSA^5- complexes are reported either from laboratory determinations using pH potentiometry, or from a detailed literature survey, or from the use of such constants in linear free energy relationships to compute the unpublished constants.

Such constants are of use in the computer simulation of the chemical speciation of multi-metal, multi-ligand complex systems such as those encountered in the environment which has been exposed to effluent containing detergents¹.

Reference

1. Gangoda, C.K. and Williams, D.R. Chemical Speciation and Bioavailability, (1997), 9(3), 1 - 11.

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