Kapok fiber oriented-polyaniline nanofibers for efficient Cr(VI) removal

Kapok fiber (KF) was combined with polyaniline (PAN) to obtain an adsorbent via in situ rapid polymerization of aniline (AN). The results indicate that KF can guide the growth orientation of PAN by which KF oriented-PAN nanofibers were developed and used as the adsorbent to remove hexavalent chromium. The effects of operating parameters including pH, contact time, Cr(VI) concentration and coexisting heavy metals were studied. The pseudo-second-order equation and three adsorption isotherms including Langmuir, Freundlich and Redlich–Peterson equations were applied to determine the adsorption rate and capacity. The results show that the as-prepared KF/PAN adsorbent has a comparable adsorption capacity with PAN at lower initial Cr(VI) concentration. Simultaneously, KF/PAN exhibits a faster adsorption rate as a result of its intrinsic large lumen. Coexisting heavy metals have no obvious effects on the adsorption capacity, suggesting that KF/PAN is a highly efficient and economically viable adsorbent for selective Cr(VI) removal.

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► A renewable resource, kapok fiber is combined with polyaniline.
► Kapok fiber can orient the growth of polyaniline nanofibers.
► Kapok fiber can accelerate the adsorption rate.
► Kapok fiber/polyaniline is a viable adsorbent for selective Cr(VI) removal.