Details

Autor(en) / Beteiligte

• Banasiak, Laura J.
• Schäfer, Andrea I.

Titel

Sorption of steroidal hormones by electrodialysis membranes

Ist Teil von

• Journal of membrane science, 2010-12, Vol.365 (1), p.198-205

Ort / Verlag

Elsevier B.V

Erscheinungsjahr

2010

Quelle

Elsevier ScienceDirect Journals

Beschreibungen/Notizen

• ▶ Strong sorption of four hormones to electrodialysis membranes was noted when treating waters containing such micropollutants. Interactions were quantified using partition coefficients. ▶ Hormones are uncharged at neutral pH and hence are not removed by ED. However, at pH 11, the negatively charged estrone permeates through the anion-exchange membrane. ▶ Micropollutant sorption decreases in the presence of humic acid due to the competition of humic acid with micropollutants for sorption sites. The mechanisms of sorption of four steroidal hormones – estradiol, estrone, progesterone and testosterone – to electrodialysis (ED) membranes were investigated as a function of solution pH and presence of humic acid (HA). Hormone-membrane partition coefficients (log K AEM/CEM) determined through sorption isotherm experiments suggested that hormone sorption was due to hydrogen bonding and cation–π interactions between hormone and membrane functional groups. Progesterone sorption at pH 7 (922 μg/cm 3) during ED was greater than estrone sorption (591 μg/cm 3) due to its greater cation-exchange membrane (CEM) bonding affinity. Estrone sorption at pH 11 (487 μg/cm 3) was reduced due to estrone dissociation and electrostatic repulsion with negatively charged CEMs. Permeation of estrone (30–100 ng/cm 2 h) through the anion-exchange membranes (AEMs) was observed. At pH 11, charge repulsion between estrone and HA coupled with AEM electrostatic attraction resulted in increased sorption. Partial membrane desorption was noted in isotherm (20–30%) and ED desorption (3.8%) experiments and was dependent on the initial mass sorbed, solution pH and resultant electrostatic interactions.