Designing Sustainable Lignin/(1→3)-α- d -Glucan Polymeric Adsorbents for Dye Removal: Insights into Structure-Sorption Relationships

Abstract The focus of this study was on synthesizing, characterizing, and implementing eco-friendly adsorbents derived from poly(ethylene glycol dimethacrylate-co-vinyl acetate-co-triethoxyvinyl silane) (Mic1=EGDMA+VA+TEVSi) or poly(ethylene glycol dimethacrylate-co-triethylene glycol dimethacrylate-co-vinyl acetate-co-triethoxyvinyl silane) (Mic2=EGDMA+TEGDM+VA+TEVSi) with the incorporation of (1→3)-α-d-glucan (Glu) and lignin (Lig) obtained from fungal biomass and wood waste, respectively. Both the starting materials and the final adsorbents were examined using such methods as ATR/FT-IR, XPS, DSC, SEM/EDX, porosity measurements, swelling behavior, and determination of the pHpzc. The pHpzc values of the adsorbents ranged from 5.38 to 6.38. The static batch method was applied to investigate the adsorptive removal of toxic dyes C.I. Acid Violet 1 (AV1) and C.I. Basic Yellow 2 (BY2). The equilibrium sorption state in the case of BY2 was promoted by Lig addition and described by the Freundlich isotherm model, with kF parameters equal to 5.11 mg1-1/nL1/n/g for Mic1/Glu+Lig and 14.95 mg1-1/nL1/n/g for Mic2/Glu+Lig. AV1 sorption was limited by monolayer formation on the adsorbent’s surface, with a capacity range of 4.5–10.9 mg/g. The presence of cationic, non-ionic, and anionic surfactants at 0.1-0.5 g/L concentration influenced the removal of AV1 and BY2 from aqueous solutions. The quantitative BY2 desorption from Mic1/Glu+Lig and Mic2/Glu+Lig was achieved using 1 M NaCl + 50% v/v MeOH and 1 M HCl + 50% v/v MeOH, while 1 M NaOH and 1 M NaOH + 50% v/v MeOH were ineffective.