Investigation of Cationic Dye Adsorption from Water onto Acetic Acid Lignin

Abstract

An adsorbent was prepared from acetic acid lignin (AAL) to investigate the adsorption mechanism of methylene blue (MB) from water. AAL was first deacetylated in NaOH aqueous solution and then fractionated by methanol to prepare adsorbents with various acidic hydroxy groups. The adsorption capacities of MB increased with the increase in initial pH and with the decrease in adsorbent dosage. The results of adsorption kinetics indicated the dye uptake process is a chemisorption. The adsorption capacity of lignin for MB adsorption increased from 18.2 to 63.3 mg g⁻¹ as AAL was deacetylated and fractionated.

KEYWORDS:

• Adsorption
• acetic acid lignin
• deacetylation
• methylene blue
• acidic hydroxy groups