Labile complexes of trace metals in aquatic humic substances: Investigations by means of an ion exchange-based flow procedure
Tóm tắt
The lability/inertness of heavy metals bound in aquatic humic substances (HS) has been characterized by means of ligand exchange with cellulose-immobilized triethylenetetramine-pentaacetic acid (TETPA) applying a flow system. On the basis of high metal distribution coefficients, Kd of 103 to 104 (ml/g) on cellulose TETPA even in slightly acidic HS solutions, labile and inert metal fractions in HS are characterized by their different kinetics and degree of phase exchange in small TETPA columns. For traces of metals bound to dissolved HS, the lability order Cd ≈ Mn(II)>Zn>Pb>Co>Ni>Cu is revealed. Systematic variation of environmentally relevant parameters shows the strong influence of the pH value and the ratio of metal loading/complexing capacity on the metal lability in HS. Surprisingly, in the case of freshly formed HS/Ni and HS/Cu complexes, slow transformation processes occur which lower their initial lability by one order of magnitude and supposedly increase their thermodynamic stability.
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Tài liệu tham khảo
Allard B, Boren H, Grimvell A (eds) (1991) Humic substances in the aquatic and terrestrial environment. Springer, Berlin Heidelberg New York
Aiken GR, McKnight DM, Wershaw RL (eds) (1985) Humic substances in soil, sediment, and water. Wiley, New York Chichester Brisbane Toronto
Frimmel FH, Christman RM (eds) (1988) Humic substances and their role in the environment. Wiley, New York Chichester Brisbane Toronto
Buffle J (1988) Complexation reactions in aquatic systems: and analytical aproach. Horwood, Chichester
Buffle J (1988) Complexation reactions in aquatic systems: an analytical approach. Horwood, Chichester, pp 195–303, 354–383
Buffle J, Tessier A, Haerdi W (1984) In: Kramer CJM, Duinker JC (eds) Complexation of trace metals in natural waters. Nijhoff/Junk, The Hague
Fish W, Morel FM (1985) Can J Chem 63:1185–1193
Cabaniss SE, Shuman MS (1990) Anal Chem 62:1528–1531
Senesi N (1990) Anal Chim Acta 232:51–75
Berggren D (1990) Int J Environ Anal Chem 41:133–148
Norden M, Ephraim JE, Allard B (1993) Talanta 40:1425–1432
Mak MSK, Langford CH (1975) Can J Chem 60:2023–2028
Shuman MS, Collins BJ (1983) In: Christman RF, Gjessing ET (eds) Aquatic and terrestrial humis materials. Ann Arbor Science, pp 349–370
Lavigne JA, Langford CH, Mak MSK (1987) Anal Chem 59:2616–2620
Finger W, Klamberg H (1992) In: Matthess G, Frimmel FH, Hirsch P, Schulz HD, Usdowski E (eds) Progress in hydrogeochemistry. Springer, Berlin Heidelberg New York, pp 67–70
Figura P, McDuffie B (1979) Anal Chem 51:120–125
Figura P, McDuffie B (1980) Anal Chem 52:1433–1439
Liu Y, Ingle JD (1989) Talanta 36:185–192
Riedel-de Haen AG (1987) Cellulose HYPHAN, Chelat-Ionenaustauscher für die Metallspurenanalyse, Seelze/Hannover
Burba P, Willmer PG (1982) Fresenius Z Anal Chem 311:222–231
Burba P (1994) Fresenius J Anal Chem 348:301–311
Burba P, Willmer PG (1992) Fresenius J Anal Chem 342:167–171
Burba P, Rocha JC, Schulte A (1993) Fresenius J Anal Chem 346:414–419
Malcolm RL (1991) In: Allard B, Boren H, Grimvall A (eds) Humic substances in the aquatic and terrestrial environment. Springer, Berlin, pp 9–36
Frimmel FH, Hopp W (1986) Fresenius Z Anal Chem 325:68–72
Spiteller M (1987) Sci Total Environ 62:47–54
Buffle J (1988) Complexation reactions in aquatic systems: an analytical approach. Horwood, Chichester, pp 600–603