Preparation, characterization and application of a novel silane-bridged polyaniline/cotton fiber composite

• Silane-bridged PANI/SCF composite was prepared by a novel two-step method.
• Grafting conditions for aniline-containing silane on CF were optimized.
• PANI layer on PANI/SCF existed as uniformly distributed nanorods.
• PANI/SCF showed much higher Cr(VI) adsorption capacity than neat PANI.

A silane-bridged polyaniline (PANI)/cotton fiber (CF) composite (designated as PANI/SCF) was prepared by a novel and facile approach in the current study. Aniline-bearing silane molecules were first grafted onto the CF surface through a condensation reaction between hydroxyl groups of cellulose and the silane molecules. Subsequent oxidative polymerization of aniline in the presence of silane-modified CF (SCF) yielded the final PANI/SCF composite, which can be used as the potential Cr(VI) adsorbent. Results showed that the optimal silane grafting conditions were: 0.01 mol/L HAc, EtOH/water volume ratio 95/5, reaction temperature 40 °C and silane dosage 0.1 g (per 0.5 g CF). Using SCF that prepared under the optimal conditions as the substrate, about 4.6% of PANI can be deposited, mostly existing as nanorods and distributing more evenly than those on the raw CF surface. FTIR and XPS analyses further testified the successful chemical bonding of silane and the final deposition of PANI on the fiber surfaces. In comparison with neat PANI, the solid–liquid separation can be achieved by simply taking the fibrous adsorbent out. Besides, the adsorption capacity of PANI/SCF on the basis of PANI mass (dividing Qm by PANI content) was much higher, probably due to the uniform distribution of PANI nanostructures on SCF and the high efficiency of PANI nanostructures in Cr(VI) adsorption.

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