Roughness measurements of the different compacted
membranes measured by optical profilometry are also pre-
sented in Table 2. No significant differences in surface
roughness were observed after permeation of 0.5 L and 2 L
MilliQ, deionized water, and tap water. Although no differ-
ences in surface roughness were observed for membranes
compacted with MilliQ (511 143 nm) and deionized water
(562 123 nm) after 5 L permeation, membranes compacted
with tap water showed highest roughness with values of
1166 147 nm. Height topography results presented in Fig. 3
showed that the surface of membranes compacted with Mil-
liQ water (Fig. 3A) had areas of very smooth surface topology
profiles and areas with irregular and heterogeneous surface
topology profiles, due to what looked like surface defects,
presumably from the manufacturing process. Topological
profiles ofmembranes compacted with deionized (Fig. 3B) and
tap water (Fig. 3C) had a consistent and homogeneous
roughness and no surface defects were observed. The surface
of NF 270 membranes compacted with tap water (Fig. 3C) had
however frequent high narrow peaks compared to the smaller
peaks obtained with the DI water compaction.