Super Functional Anionic Hydrolysis Lignin for Capturing Dyes

Hydrolysis lignin is a major product of the enzymatic fractionation of lignocellulosic biomass and its functionalization plays a crucial role in valorizing this material. In this work, functional hydrolysis lignin-derived polymer (hydrolysis lignin-acrylic acid polymer, AA-HL) was generated to act as an adsorbent and coagulant for eliminating ethyl violet (EV) dye from solutions. AA-HL was partially soluble in water. The soluble fraction of the lignin polymer in the coagulation studies led to the complete dye removal from the solutions at a 6 mg/g dosage following the charge neutralization mechanism. The performance of insoluble AA-HL as an adsorbent was also investigated using a Quartz crystal microbalance with dissipation (QCM-D), and the results indicated the great adsorption of the dye to the insoluble AA-HL. The high stability of AA-HL adsorbent was also confirmed in the dye adsorption process at 40 ?C. Furthermore, the dye adsorption on AA-HL was promoted by increasing the ionic strength of the solution to 500 mM NaCl, suggesting the existence of the strong hydrophobic interaction between the dye moiety and AA-HL. The results suggested that soluble and insoluble super functional lignin derivatives can be produced from hydrolysis lignin with a strong affinity toward dyes.