Studying the Effect of Shortening Carbon Nanotubes via Ball Milling on Cellulose Acetate Nanocomposite Membranes for Desalination Applications

Abstract

Studying the effect of different sizes of multi-walled carbon nanotubes (CNTs) on mixed matrix membranes in nanofiltration applications has not been widely reported in the literature. In this study, two different lengths of functionalized CNTs were used to investigate such effect. First, CNTs were shortened by using high-energy ball milling at 400 RPM, with a ball-to-powder weight ratio (BPR) of 120:1. Characterization of the structure of the CNTs was carried out using TEM, XRD, SEM, BET, and Raman Spectroscopy. Second, 0.001 wt % of unmilled and milled CNTs were incorporated into cellulose acetate nanocomposite membranes, Eli-0 (unmilled), and Eli-400 (milled at 400 RPM) to study their effects on the membranes’ morphology, porosity, hydrophilicity, and performance analysis in terms of permeation and salt retention rates of 5000 ppm Na2SO4. Results showed that shortening CNTs enhanced the membranes’ hydrophilicity and affected macrovoid and micropore formation. Furthermore, shortening CNTs resulted in opening their caps and improved the permeation rates with a slight adverse effect on salt retention.

Cellulose Acetate-Based Materials for Water Treatment in the Context of Circular Economy

“…A solution is represented by the preparation of composite membranes to stiffen the polymer matrix and at the same time to improve the separation properties. For desalination processes, cellulose acetate membranes are usually composited with fillers that have a high salts absorption capacity, the most frequently used being carbon nanotubes and graphene [77][78][79][80]. A more accessible type of fillers for this application is represented by zeolites.…”

Prospects of Polymeric Nanocomposite Membranes for Water Purification and Scalability and their Health and Environmental Impacts: A Review

“…[ 14 , 16 ]. Organic polymers, primarily polysulfone (PSF) [ 48 , 49 , 50 , 51 , 52 ], poly(ether sulfone) (PES) [ 53 ], polyacrylonitrile (PAN) [ 54 , 55 ], polyamide [ 56 , 57 ], polyimide [ 58 , 59 ], cellulose acetate membrane [ 60 , 61 , 62 , 63 ], polylactic acid [ 64 , 65 , 66 , 67 ], polyvinyl alcohol (PVA) [ 68 , 69 , 70 ], poly-(vinylidene fluoride) (PVDF) [ 71 , 72 , 73 , 74 ], and polytetrafluoroethylene (PTFE) [ 75 , 76 , 77 ], are all often employed in water filtering membranes.…”

New Hybrid Nanofiltration Membranes with Enhanced Flux and Separation Performances Based on Polyphenylene Ether-Ether-Sulfone/Polyacrylonitrile/SBA-15

“…The literature on ultrafiltration and nanofiltration membranes strongly suggests that the most widely-used polymers are polysulfone (PS), polyethersulfone (PES), polyacrylonitrile (PAN), polypropylene (PP), polytetrafluoroethylene (PTFE), polyamide (PA), and cellulose acetate (CA) [ 9 , 10 , 11 , 12 , 13 ].…”