Surfactant grafted PDA-PAN nanofiber: Optimization of synthesis, characterization and oil absorption property

•Synthesizing of a superhydrophobic and oleophilic nanofiber.•Preparation of a high absorption capacity absorbent for the removal of oil sillage.•Functionalization of PAN polymer with dopamine through a covalent linkage.•Optimization the condition of functionalization and grafting processes.

In this paper, surfactant grafted polydopamine (PDA)-polyacrylonitrile (PAN) nanofiber with the aim of separation the oil spillage was synthesized. Firstly, the electrospun PAN nanofiber was functionalized by dopamine in an alkali condition. Secondly, the Tergitol as a nonionic surfactant was grafted onto the surface of functionalized PAN nanofiber. The conversion amount (Cn%) of nitrile group to amidine group and the grafting yield of surfactant on the surface of PAN nanofiber were evaluated. Also, the optimum conditions in functionalization and grafting processes were reported. In order to characterize the synthesized nanofibers, FTIR, SEM, AFM, XPS and BET analyses were used. The pore size distribution of synthesized nanofibers was investigated by BJH method. The results showed that the dopamine and surfactant were attached to the nanofiber surface through the covalent linkages. SEM images exhibited the deposition of a dense layer on the surface of grafted nanofibers. Moreover, AFM analysis revealed that the surface of nanofiber became rough after the functionalization and grafting processes. In order to evaluate the superhydrophobic properties of nanofibers, contact angle and surface energy analyses were investigated. The synthesized absorbent showed a high absorption capacity of 148.58 and 62.53 g/g for heavy motor oil and diesel fuel, respectively. The absorbed oil was easily removed by a vacuum filtration and the nanofiber could be reused for several cycles while keeping high absorption capacity.

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