Lignin/Chitin Films and Their Adsorption Characteristics for Heavy Metal Ions

This study presents the fabrication of novel lignin/chitin films from a solvent system composed of the ionic liquid 1-butyl-3-methylimidazolium acetate and γ-valerolactone as a biosourced cosolvent. Scanning electron microscopy and attentuated total reflectance Fourier transform infrared spectroscopy confirmed the successful preparation of the lignin/chitin films. The application of lignin/chitin film as an adsorbent for Fe(III) and Cu(II) cation uptake from aqueous solutions is discussed. It was observed that the maximum adsorption capacity for Fe(III) was 84 wt % and for Cu(II) was 22 wt % within 48 h. The lignin/chitin films could be regenerated by desorption of the Fe(III) and Cu(II) ions. Up to 12 and 46 wt %, respectively, could be released within 48 h by directly soaking the metal ion loaded film within water at room temperature. The lignin/chitin film can be considered as a stable and recyclable bioadsorbent material with a high adsorption metal ion capacity for water purification.