Degradation of tributyltin chloride in water photoinduced by iron(III)

The degradation of tributyltin chloride (TBT) photoinduced by iron(III) was investigated. Upon irradiation at lambda(excitation) >300 nm a photoredox process was observed, yielding iron(II) and (OH)-O-. radicals. The disappea rance of TBT was proved to involve only an attack by (OH)-O-. radicals: the quantum yield of TBT disappearance was determined. A wavelength effect was observed; the shorter the excitation wavelength, the higher the rate of TB T disappearance. Most of the photoproducts were identified and the mechanis m of degradation was elucidated. The main route to degradation is a stepwis e debutylation of TBT to di- and mono-butyltin with final formation of inor ganic tin. The complete mineralization of TBT was achieved with long irradi ation times, leading to innocuous inorganic tin. Copyright (C) 1999 John Wi ley & Sons, Ltd.