Enantiomeric selectivity in adsorption of chiral beta-blockers on sludge

Edmond Sanganyado, Qiuguo Fu, Jay Gan

Research output: Contribution to journalArticlepeer-review

25 Citations (Scopus)

Abstract

Adsorption of weakly basic compounds by sludge is poorly understood, although it has important implications on the distribution and fate of such micropollutants in wastewater effluent and sludge. Additionally, many of these compounds are chiral, and it is likely that their interactions with sludge is stereoselective and that the process may be further modified by surfactants that coexist in these systems. Adsorption of (R) and (S)-enantiomers of five commonly used β-blockers, i.e., acebutolol, atenolol, metoprolol, pindolol and propranolol, on sludge was characterized through batch experiments. Stereoselectivity in adsorption increased with decreases in hydrophobicity of the β-blockers. The enantiomeric fraction (EF) of the amount of acebutolol, atenolol and metoprolol sorbed on sludge were 0.27, 0.55 and 0.32, respectively. Thus, Kd values of the (S)-enantiomers of acebutolol and metoprolol were approximately twice that of the (R)-enantiomer, that is, 109 ± 11 and 57 ± 8 L/kg compared to 52 ± 13 and 22 ± 8 L/kg, respectively. There was no statistically significant difference in Kd values of the enantiomers of pindolol and propranolol, suggesting stereoselectivity in adsorption was likely driven by specific polar interactions rather than hydrophobic interactions. The EF value of atenolol decreased from 0.55 ± 0.03 to 0.44 ± 0.04 after modifying the sludge with Triton X 100. These results suggested that surfactants altered adsorption of β-blockers to sludge, likely by forming ion pair complexes that promote hydrophobic interactions with the solid surfaces.
Original languageEnglish
Pages (from-to)787-794
JournalEnvironmental Pollution
Volume214
Early online date4 May 2016
DOIs
Publication statusPublished - 1 Jul 2016
Externally publishedYes

Fingerprint

Dive into the research topics of 'Enantiomeric selectivity in adsorption of chiral beta-blockers on sludge'. Together they form a unique fingerprint.

Cite this