Nanomembranes - Nanotechnologies for Water Environment Applications - page 381

fullerene C 60 were studied on removal and adsorptive behaviors of estrogenic
compounds. Scanning electron microscope (SEM) observation suggested an increase in
the pore size and porosity in the top layer of fullerene-containing membranes compared
to pure PPO membrane. Moreover, cross-section of PPO membrane had sponge-like
structure while membranes containing C 60 (2% and 10%) had finger-like structure. As a
result, the permeate flux increased with the increased percentage of fullerene in
membrane. However the removal of estrone by PPO membrane with 10% fullerene did
not decrease obviously compared with the one without fullerene although the flux
increased by about eight times. It was observed in Table 12.5 (extracted from Jin et al.,
2007b) that all of the three kinds of membrane showed very good removal of estrone
(more than 96%). C 60 -containing membranes also demonstrate better absorption capacity
than PPO membrane. Results for long-term filtration showed that the 10%wtC 60 -PPO
membrane was able to maintain its excellent removal performance of at least 95%.

Table 12.5 Concentrations and removal of estrone in dead-end filtration tests.
Amount of Estrone in

Estrone
Removal
(%)

Membrane

Feedwater
(ng)

Permeate (ng) Retenate (ng)

PPO 750 14 248 97.2

2wt% C 60 -PPO 750 6 162 98.8

10wt% C 60 -PPO 750 16 208 96.8

12.2.3.3 Removal of PhACs

Similar to the steroid hormones, pharmaceuticals as environmental contaminants
did not receive a great deal of attention until the link was established between a synthetic
birth-control pharmaceutical (ethynylestradiol) and impacts on fish (Purdom et al., 1994;
Desbrow et al., 1998; Jobling et al., 1998; Snyder et al., 2001a, b). Kim et al. (2007)
measured the concentrations of 14 pharmaceuticals, 6 hormones, 2 antibiotics, 3
personal care products (PCPs), and 1 flame retardant in surface waters and wastewater
treatment plant effluents in South Korea. Tris (2-chloroethyl) phosphate (TCEP),
iopromide, naproxen, carbamazepine, and caffeine were quite frequently observed (>
80%) in both surface waters and effluents. However, the primary estrogen hormones,
17-ethynylestradiol and 17-estradiol, were rarely detected, while estrone was detected
in both surface water and wastewater effluent. Kimura et al. (2003) studied the removal
of three PhACs, phenacetine, diclofenac, and primidone, at a concentration of
approximately 100 ng/l each, where all three PhACs were mixed in one feed solution
(i.e., a cocktail solution). Two flat sheet thin film composite membranes were employed
in this study. The ESNA (Hydranautics, Oceanside, CA) is classified as NF, and the RO-
XLE (Film-Tec, Vista, CA) is classified as ultra-low pressure RO. The rejection varied
from 14 to 72% by NF and 65 to 78% by RO. For the antibiotic sulfamethoxazole no