Nanocomposite Membrane with Different Carbon Nanotubes Location for Nanofiltration and Forward Osmosis Applications

Abstract

We investigated the effect of carbon nanotubes (CNTs) location on the property and performance of prepared membranes. Four different types of membranes were prepared, including (1) thin film composite (TFC, polyamide active layer on polysulfone substrate), (2) nanocomposite-supported thin film composite (nTFC, polyamide active layer on CNT-embedded polysulfone substrate), (3) thin film nanocomposite (TFN, CNT-incorporated polyamide active layer on polysulfone substrate), and (4) nanocomposite-supported thin film nanocomposite (nTFN, CNT-incorporated polyamide active layer on CNT-embedded polysulfone substrate). The water permeability followed the sequence of nTFN > TFN > nTFC > TFC. However, the rejection and salt permeability exhibited the opposite trend. The incompatibility between CNTs and polymers provided nanocorridors, through which both water and solutes could pass. The nTFN membrane exhibited the highest porosity and lowest structural parameter. Moreover, the nTFN membrane possessed the best antifouling capacity by preventing foulants to attach to the surface and clog the substrate pores. This work offered some systematic knowledge to design novel membranes with improved performance for desalination and water purification applications.

Surface-Controlled Water Flow in Nanotube Membranes

“…As nanotubes, and now 2D materials, are incorporated in mixed matrix membranes or fabricated as stand-alone membranes, elucidating the origin of the flow enhancement phenomenon remains crucial to tailor the materials for specific applications, ranging from seawater desalination 4 to removal of pollutants in nanofiltration. 5 The effect of confinement has been well-researched and is now well understood, including a threshold below which continuum fluid mechanics no longer applies, 6 the presence of slip, i.e. low resistance to liquid flow, 7 and how both are affected by the curvature of the tube.…”

Wastewater remediation via combo-technology

“…They are highly porous and have very large surface area. However, they have not been very successful in water desalination due to various limitations [35]. They work by UF, FO, and RO processes to purify water containing heavy metals, organic and inorganic pollutants, microbial pathogens, etc.…”

Fabrication of Carbon Nanotube Membrane for Enhanced Performance in Forward Osmosis Process

“…The surface roughness also increases with the increase of CNTs concentration increased. It is worthy to note that the higher roughness, the larger surface area is available for membrane transport, which favors the improvement of the membrane flux [11]. .…”