1 research outputs found
Effective Antiscaling Performance of Reverse-Osmosis Membranes Made of Carbon Nanotubes and Polyamide Nanocomposites
The antiscaling properties of multiwalled
carbon nanotube (MWCNT)–polyamide
(PA) nanocomposite reverse-osmosis (RO) desalination membranes (MWCNT–PA
membranes) were studied. An aqueous solution of calcium chloride (CaCl<sub>2</sub>) and sodium bicarbonate (NaHCO<sub>3</sub>) was used to precipitate
in situ calcium carbonate (CaCO<sub>3</sub>) to emulate scaling. The
MWCNT contents of the studied nanocomposite membranes prepared by
interfacial polymerization ranged from 0 wt % (plain PA) to 25 wt
%. The inorganic antiscaling performances were compared for the MWCNT–PA
membranes to laboratory-made plain and commercial PA-based RO membranes.
The scaling process on the membrane surface was monitored by fluorescence
microscopy after labeling the scale with a fluorescent dye. The deposited
scale on the MWCNT–PA membrane was less abundant and more easily
detached by the shear stress under cross-flow compared to other membranes.
Molecular dynamics simulations revealed that the attraction of Ca<sup>2+</sup> ions was hindered by the interfacial water layer formed
on the surface of the MWCNT–PA membrane. Together, our findings
revealed that the observed outstanding antiscaling performance of
MWCNT–PA membranes results from (i) a smooth surface morphology,
(ii) a low surface charge, and (iii) the formation of an interfacial
water layer. The MWCNT–PA membranes described herein are advantageous
for water treatment