TY - JOUR
T1 - Adsorption and transformation of tetracycline antibiotics with aluminum oxide
AU - Chen, Wan Ru
AU - Huang, Ching Hua
PY - 2010/5/1
Y1 - 2010/5/1
N2 - Tetracycline antibiotics (TCs) including tetracycline (TTC), chlorotetracycline (CTC) and oxytetracycline (OTC) adsorb strongly to aluminum oxide (Al2O3), and the surface interaction promotes structural transformation of TCs. The latter phenomenon was not widely recognized previously. Typically, rapid adsorption of TCs to Al2O3 occurs in the first 3h ([TC]=40μM, [Al2O3]=1.78gL-1, pH=5, and T=22°C), followed by continuous first-order decay of the parent compound (kobs=15±1.0, 18±1.0 and 6.2±0.9×10-3h-1 for TTC, CTC and OTC, respectively) and product formation. The transformation reaction rate of TCs strongly correlates with adsorption to Al2O3 surfaces. Both adsorption and transformation occur at the highest rate at around neutral pH conditions. Product evaluation indicates that Al2O3 promotes dehydration of TTC to yield anhydrotetracycline (AHTTC), epimerization of TTC, and formation of Al-TTC complexes. Al2O3 promotes predominantly the transformation of CTC to iso-CTC. The surface-bound Al(+III) acts as a Lewis acid site to promote the above transformation of TCs. Formation of AHTTC is of special concern because of its higher cytotoxicity. Results of this study indicate that aluminum oxide will likely affect the fate of TC antibiotics in the aquatic environment via both adsorption and transformation.
AB - Tetracycline antibiotics (TCs) including tetracycline (TTC), chlorotetracycline (CTC) and oxytetracycline (OTC) adsorb strongly to aluminum oxide (Al2O3), and the surface interaction promotes structural transformation of TCs. The latter phenomenon was not widely recognized previously. Typically, rapid adsorption of TCs to Al2O3 occurs in the first 3h ([TC]=40μM, [Al2O3]=1.78gL-1, pH=5, and T=22°C), followed by continuous first-order decay of the parent compound (kobs=15±1.0, 18±1.0 and 6.2±0.9×10-3h-1 for TTC, CTC and OTC, respectively) and product formation. The transformation reaction rate of TCs strongly correlates with adsorption to Al2O3 surfaces. Both adsorption and transformation occur at the highest rate at around neutral pH conditions. Product evaluation indicates that Al2O3 promotes dehydration of TTC to yield anhydrotetracycline (AHTTC), epimerization of TTC, and formation of Al-TTC complexes. Al2O3 promotes predominantly the transformation of CTC to iso-CTC. The surface-bound Al(+III) acts as a Lewis acid site to promote the above transformation of TCs. Formation of AHTTC is of special concern because of its higher cytotoxicity. Results of this study indicate that aluminum oxide will likely affect the fate of TC antibiotics in the aquatic environment via both adsorption and transformation.
UR - http://www.scopus.com/inward/record.url?scp=77951652716&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=77951652716&partnerID=8YFLogxK
U2 - 10.1016/j.chemosphere.2010.03.020
DO - 10.1016/j.chemosphere.2010.03.020
M3 - Article
C2 - 20378149
AN - SCOPUS:77951652716
VL - 79
SP - 779
EP - 785
JO - Chemosphere
JF - Chemosphere
SN - 0045-6535
IS - 8
ER -