Novel nanocomposite Kevlar fabric membranes: Fabrication characterization, and performance in oil/water separation

• Published in: Applied surface science 2014-02, Vol.293, p.275-286
• Main Authors: Karimnezhad, Hanieh, Rajabi, Laleh, Salehi, Ehsan, Derakhshan, Ali Ashraf, Azimi, Sara
• Format: Article
• Language: English
• Subjects: Alumoxane; Coating; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Membrane; Nanostructure; Oily water; Physics
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2013.12.149

•Membranes were prepared through three-step dip coating of Kevlar fabrics.•The super hydrophilic membrane offered an excellent oil/water separation.•The performance of the membranes was satisfactory.•The majority of fouling occurred as gel layer on the surface of membranes.•The membranes were successfully regenerated by a simple cleaning method. Nanocomposite membranes with hydrophilic surface were fabricated for separation of oil (n-hexane) from oil/water emulsion. Three different nanomaterials namely, para-aminobenzoate alumoxane (PAB-A), boehmite-epoxide and polycitrate alumoxane (PC-A) were coated on the Kevlar fabric (support), according to a three-step dip-coating protocol. FTIR, SEM, TEM, UV/vis spectrophotometer, and wettability analyses were used to characterize the composite membranes. The three coating layers interacted chemically with one another and also physically with the Kevlar fabric. Water uptake measurements indicated that the membrane is a hydrophilic one. SEM and TEM analyses showed the smooth surface of the composite membrane and three-dimensional dendrimeric hyper-branched structure of (PC-A), respectively. A dead-end filtration setup was applied to test the membranes performance under natural gravity force. Effect of pH as an important variable affecting separation process was investigated with the neutral pH provided the optimum condition for the separation. Oil rejection and permeate fluxes were also monitored. The optimum flux and rejection obtained, were 7392 (Lm−2h−1) and 89.06% at pH 7, respectively. Fouling occurred as a gel layer on the membrane surface. The deposited oil droplets on the surface of the membrane were successfully washed away with satisfactory permeate flux recovery (FRR=88.88% at neutral pH), using hot distilled water and acidic solution as eluents.