Nanocomposite hollow fiber nanofiltration membranes: Fabrication, characterization, and pilot‐scale evaluation for surface water treatment

Abstract

Thin-film nanocomposite (TFN) membranes were fabricated by interfacial polymerization of a polyamide (PA) layer on the shell side of hollow fiber membrane supports. TiO 2 nanoparticle loadings in the thin-film layer were 0.01, 0.05, and 0.20 wt %. Nanoparticle-free PA thin-film composite (TFC) membranes served as the comparative basis. The TFN membranes were characterized in terms of the chemical composition, structure, and surface properties of the separation layer. Incorporating nanoTiO 2 improved membrane permeability up to 12.6-fold. During preliminary laboratory-scale evaluation, TFN membranes showed lower salt rejection but higher TOC rejection in comparisons with the corresponding values for TFC controls. Based on the performance in lab-scale tests, TFN membranes with 0.01 wt % nanoTiO 2 loading were selected for an evaluation at the pilot scale with synthetic surface water as the feed. While the permeate flux during long-term pilot-scale operation gradually decreased for TFC membranes, TFN membranes had a higher initial permeate flux that gradually increased with time. The TOC rejection by TFN and TFC membranes was comparable. We conclude that TFN membranes show promise for full-scale surface water treatment applications.

Effects of polyvinylidene fluoride substrate characteristics on the selectivity of thin‐film composite nanofiltration membrane

“…PVDF is rarely used as the substrate of TFC membranes due to its high hydrophobicity. [10][11][12][13] However, the surface hydrophilicity of the PVDF substrates can be improved by adding hydrophilic modifiers, such as metal oxides [14][15][16][17] and graphene materials, [18][19][20][21][22] or treated with plasma 23 or alkaline. 24 Then effective PA layer can be made on such PVDF substrates.…”

Hollow Fiber Membrane for Organic Solvent Nanofiltration: A Mini Review

“…Commercialization of HF OSN membranes requires the study of HF OSN membranes at an industrial scale. The common length of commercial HF components is 1–2 m (40–80 inches) with a diameter of 10–20 cm (4–8 inches) [ 17 , 153 , 154 ], while the HF modules used by academia are usually less than 40 cm in length and less than 25 cm (1 inch) in diameter [ 43 , 87 ]. The difference of module size makes a significant gap between HF OSN modules fabricated and tested at laboratory scale and those produced and operated at industrial scale, since a significant increase in length leads to significant changes in process parameters under similar operating conditions [ 153 , 155 ].…”

Comparative impact of SiO2 and TiO2 nanofillers on the performance of thin‐film nanocomposite membranes

“…Several recent investigations have considered the addition of nanomaterials as "nanofillers" in the polymer matrix to increase the antifouling resistance of membranes, primarily through alterations in surface charge and hydrophobicity of membrane in surfaces water treatment applications. [6][7][8][9][10] Inorganic particles such as graphene oxides, [11,12] carbon nanotubes (CNTs), [3,13,14] silica (SiO 2 ), [15,16] and titanium dioxide (TiO 2 ), [14,17,18] when added to the PA layer of thin-film composites, have been observed to improve hydrophilicity and reduce fouling. TiO 2 is one such promising nanofiller that may be used to improve properties of both the rejecting skin and support layers of membranes due to its relatively high hydrophilicity, [19,20] low toxicity, and environmental compatibility.…”