Safranin-O Dye Removal from Aqueous Solution Using Superabsorbent Lignin Nanoparticle/Polyacrylic Acid Hydrogel

Abstract

Alkali lignin (AL) modified by ethylene glycol and lignin nanoparticles (LN) was
prepared through the acid precipitation technology. Lignin nanoparticle/polyacrylic
acid (LN/PAA) hydrogel was prepared using copolymerization reactions. LN and
LN/PAA hydrogel were investigated using GPC, SEM, FT-IR spectroscopy, and TGA-DTG
analysis. The sizes of the nanoparticles were assessed using DLS. LN/PAA hydrogel was
used to remove Safranin-O from an aqueous Solution. The optimal conditions for
absorption provided at pH 7, an initial concentration of dye of 1.5 gr.L-1, and an
adsorbent dosage of 0.1 gr. Also, the optimal time for LN and LN/PAA hydrogel were
100 min and 450 min, respectively. Both absorbent LN and LN/PAA hydrogel showed
good agreement with the Langmuir isotherm. The maximum absorption capacities of
LN and LN/PAA hydrogel were determined to be 100 mg.gr-1 and 1666.6 mg.gr-1,
respectively. Both absorbent LN and LN/PAA hydrogel follow the pseudo-second
kinetic model and the intraparticle diffusion model.