Surface decoration of bis-aminosilane cross-linked multiwall carbon nanotube ultrafiltration membrane for fast and efficient heavy metal removal

• Published in: npj clean water 2022-09, Vol.5 (1), p.1-13, Article 44
• Main Authors: Pandey, Ravi P., Ouda, Mariam, Abdul Rasheed, P., Banat, Fawzi, Hasan, Shadi W.
• Format: Article
• Language: English
• Subjects: 639/301/357; 704/172/169/896; Ammonium; Ammonium chloride; Aquatic Pollution; Carbon; Chloride; Composite materials; Copper; Crosslinking; Earth and Environmental Science; Environment; Heavy metals; Industrial pollution; Industrial wastes; Industrial wastewater; Lead; Membrane permeability; Membranes; Multi wall carbon nanotubes; Nanomaterials; Nanotechnology; Nickel; Permeability; Pollutants; Polymerization; Polymers; Ring opening; Ultrafiltration; Waste Water Technology; Wastewater; Wastewater pollution; Water Industry/Water Technologies; Water Management; Water pollution; Water Pollution Control; Water Quality/Water Pollution; Zinc
• ISSN: 2059-7037; 2059-7037
• DOI: 10.1038/s41545-022-00189-8

Heavy metals (HMs) are highly toxic water pollutants abundant in industrial wastewater. Herein, a bis[3-(trimethoxysilyl)propyl]amine (BTMSPA) cross-linked multiwalled carbon nanotube (MWCNT) nanomaterial (CQACNT) was synthesized by silanization of MWCNT-OH followed by grafting of positively charged quaternary ammonium groups (glycidyl trimethyl ammonium chloride (GTMAC)) by an epoxide ring-opening reaction. The composite membranes were prepared by the incorporation of CQACNT into the poly(ether sulfone) (PES) polymer matrix. The CQACNT-6 composite membrane exhibited a 3.5-fold increase in pure water permeability (PWP; 312.8 L m −2  h −1  bar −1 ) as compared to the pristine PES (CQACNT-0) membrane (89.6 L m −2  h −1  bar −1 ). Moreover, the CQACNT-6 composite membrane showed high HM removal rates (Pb: 89.53%; Ni: 90.42%; Cu: 91.43%; Zn: 91.86%) as compared to the CQACNT-0 membrane (Pb: 39.73%; Ni: 40.32%; Cu: 42.52%; and Zn: 43.91%). After 9 treatment cycles, the CQACNT-6 membrane retained up to 87%, and 94% of its initial PWP and initial Cu 2+ rejection, respectively, compared to only 58%, and 54%, respectively for pristine CQACNT-0. The positively charged quaternary ammonium groups enhanced the surface features of PES and MWCNTS, resulting in competitive HM removal rates due to the electrostatic repulsion between the HM and the porous membranes, as well as high PWP.