Aluminum complexation by catechol as determined by ultraviolet spectrophotometry

Journal Article · Wed Mar 01 04:00:00 EST 1989 · Environ. Sci. Technol.; (United States)

DOI:https://doi.org/10.1021/es00180a013· OSTI ID:6103173

Sikora, F J; McBride, M B

Methods of ultraviolet (UV) spectrophotometry were used to determine the stoichiometry and association constant for the Al-catechol complex from pH 3.8 to 4.6. Job's method of continuous variation indicated the Al-catechol complex had a 1:1 stoichiometry in the pH range studied. Aluminum titrations of catechol and pH titrations of catechol plus Al resulted in a shift in the UV spectra due to the formation of an Al-catechol complex absorbing UV radiation uniquely different than that of free catechol. General equations were developed for the determination of association constants assuming an organic and Al-organic complex absorb UV radiation. Aluminum titrations with constant catechol concentration yielded a log k/sub 0.1//sup c/ of 16.22 for a 1:1 Al-catechol complex. Calculated absorbance as a function of pH agree dwell with experimental pH titrations of solutions containing catechol plus Al. The fact that Al can be complexed by catechol at low pH indicates the o-hydroxy group provides a potential source for Al complexation in soil and surface waters.

• Research Organization: Cornell Univ., Ithaca, NY (USA)
• OSTI ID: 6103173
• Journal Information: Environ. Sci. Technol.; (United States), Journal Name: Environ. Sci. Technol.; (United States) Vol. 23:3; ISSN ESTHA
• Country of Publication: United States
• Language: English

Related Subjects

510200* -- Environment
Terrestrial-- Chemicals Monitoring & Transport-- (-1989)
520200 -- Environment
Aquatic-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
ALUMINIUM COMPLEXES
AROMATICS
CHEMICAL COMPOSITION
COMPLEXES
DEVELOPERS
ELECTROMAGNETIC RADIATION
EQUATIONS
HYDROXY COMPOUNDS
ORGANIC COMPOUNDS
PHENOLS
POLYPHENOLS
PYROCATECHOL
RADIATIONS
SOILS
SPECTROPHOTOMETRY
STOICHIOMETRY
SURFACE WATERS
ULTRAVIOLET RADIATION