Rejection of pharmaceuticals and personal care products (PPCPs) and endocrine disrupting chemicals (EDCs) by low pressure reverse osmosis membranes.
This paper aims to elucidate retention characteristics of some pharmaceuticals and personal care products (PPCPs), and endocrine disrupting chemicals (EDCs), by two polyamide low pressure reverse osmosis (LPRO) membranes. Feed solution pH did not have an influence on rejections of undissociated solutes, which was most likely governed by adsorption, size exclusion and diffusion simultaneously. Size exclusion was presumably dominant, especially with tight membranes (UTC-70U). Rejections of the solutes with low dipole moment (<1.0 debye) decreased with increasing octanol-water partition coefficient (K(ow)). The solutes with large K(ow) values were most likely adsorbed on membrane and subsequently passed through it resulting in larger diffusion coefficient (D(p)). The rejections decreased with increasing D(p) values irrespective of their dipole moments. Rejections of solutes with comparatively larger dipole moments might be dominated by diffusion and/or convection rather than their hydrophobicity. However, rejections of solutes with hydroxyl and carboxyl functional groups by UTC-60 increased with solution pH. More than 80% rejections were obtained for degree of dissociation (alpha)>0.5. Electrostatic repulsion played a key role for rejection of dissociated solutes, especially by loose LPRO membranes. Therefore, assessing the dissociation degree at desired pH values can be a key step to obtain an insight of rejection mechanisms by polyamide membranes.
Ozaki
H
H
Department of Civil Engineering, Osaka Sangyo University, 3-1-1 Nakagaito, Daito City, Osaka, Japan. ozaki@ce.osaka-sandai.ac.jp
Ikejima
N
N
Shimizu
Y
Y
Fukami
K
K
Taniguchi
S
S
Takanami
R
R
Giri
R R
RR
Matsui
S
S
D000327:Adsorption; D002850:Chromatography, Gel; D052244:Endocrine Disruptors / Q000302:isolation & purification*; D004867:Equipment Design; D006795:Household Products / Q000032:analysis; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008564:Membrane Potentials; D009995:Osmosis; D004364:Pharmaceutical Preparations / Q000302:isolation & purification*; D014462:Ultrafiltration / Q000379:methods; D014505:Urban Population; D014865:Waste Disposal, Fluid / Q000295:instrumentation / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000302:isolation & purification; D018508:Water Purification / Q000379:methods*; D014881:Water Supply / Q000592:standards
D052244:Endocrine Disruptors; D004364:Pharmaceutical Preparations; D014874:Water Pollutants, Chemical