Experimental determination of ampicillin adsorption to nanometer-size Al2O3 in water.
Transport of antibiotics in soil-water systems is controlled in part by adsorption to nanometer-size (10(-9)m) particles. Batch adsorption experiments were performed with ampicillin, a common amphoteric antibiotic, and 50 nm-Al(2)O(3) (alpha-alumina) at different pH conditions. Sorption to Al(2)O(3) can be described by linear isotherms for 2.9 microM-2.9 mM ampicillin concentrations. Distribution coefficients (K(d)) are 11.1 (+/-0.32)L kg(-1) at pH 2, 0.55 (+/-.04) L kg(-1) at pH 4, 21.9 (+/-0.9) L kg(-1) at pH 6, and 39.5 (+/-2.2) L kg(-1) at pH 8. At pH 2, approximately 47% of the initially adsorbed drug was removable by rinsing, at pH 4-56% was removed. Only 7% of the drug could be removed by rinsing at pH 6, and 3% at pH 8. Weak electrostatic forces dominate at pH<4, and stronger attachment mechanisms at higher pH. Low yields in rinsing (desorption) experiments at pH6 indicate strong attachment mechanisms, either electrostatic or possibly surface complexation.
Peterson
Jonathan W
JW
Department of Geological & Environmental Sciences, Hope College, PO Box 9000, Holland, MI 49422-9000, USA. peterson@hope.edu
Burkhart
Rachel S
RS
Shaw
Drew C
DC
Schuiling
Amanda B
AB
Haserodt
Megan J
MJ
Seymour
Michael D
MD
D000327:Adsorption; D000537:Aluminum Oxide / Q000737:chemistry*; D000667:Ampicillin / Q000032:analysis / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*
D014874:Water Pollutants, Chemical; D000667:Ampicillin; D000537:Aluminum Oxide