Synthesis and characterization of a carbon nanotube/polymer nanocomposite membrane for water treatment

Multi-wall carbon nanotube (MWCNT)/aromatic polyamide (PA) nanocomposite membranes were synthesized by a polymer grafting process. Surface morphology, roughness, and mechanical strength of the resultant nanocomposite membranes were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), and micro-strain analysis, respectively. SEM and AFM images showed that MWCNTs were well dispersed in the PA matrix. Measurements of mechanical properties of this composite showed increasing membrane strength with increasing MWCNT content with monotonic increases in Young's modulus, toughness, and tensile strength. The addition of MWCNTs also improved the rejection of both salt and organic matter relative to the 10% PA membrane base case. The nanocomposite membrane synthesized with 15 mg/g MWCNT in a 10% PA casting solution rejected NaCl and humic acid by factors of 3.17 and 1.67 respectively relative to the PA membrane without MWCNTs, while membrane permeability decreased by 6.5%.

Research highlights
► Multi-wall carbon nanotube (MWCNTs)/aromatic polyamide (PA) nanocomposite membranes by polymer grafting.
► SEM, AFM, FTIR and mechanical for membrane characterization.
► RO performance by permeability of ultrapure water and rejection of salts.
► Humic acid for water treatment.