Synthesis and Properties of Poly (N‐Ethyl Isatin Biphenyl Fluorenes) as Efficient and Recyclable Adsorbent for Chromium ( <scp>III</scp> ) From Aqueous Solutions

ABSTRACT Poly (N‐ethylisatin biphenyl fluorene) was successfully prepared via superacid promoted polymerization. The chemical structure of the polymer was confirmed by FT‐IR and NMR spectroscopy. The polymer exhibited high molecular weight as estimated from light scattering technique. The crystallinity, morphology, and thermal properties were investigated through XRD, SEM images, and TGA analysis. Metal sorption experiments were performed to assess the ability of poly (N‐ethylisatin biphenyl fluorene) to adsorb Cr(III) ions from aqueous solutions. The polymer adsorption of Cr(III) was strongly dependent on pH. The highest adsorption was observed at pH 5.0. The Cr(III) adsorption was proportionally dependent on the adsorbent mass and time of interaction. Metal desorption via repeated sorption cycles revealed high efficiency and good recyclability. Poly (N‐ethylisatin biphenyl fluorene) turned out to be a promising candidate for the removal of Cr(III) from aqueous solutions.