LAUSR

In this work, oxidized and sulfomethylated lignin was used as a flocculant for aluminum oxide suspension. The oxidized sulfomethylated lignin (OSML) samples had a similar charge density (− 3.5 μeq/g) but varied molecular weights (between 26 and 46 kg/mol). The performance of the produced flocculants was evaluated in altering the relative turbidity and zeta potential of the aluminum oxide suspension. The chord length of particles was increased the most in the suspension by adsorbing OSML with the highest molecular weight. The flocs strength analysis revealed that the flocculation process was reversible. Flocculation analysis depicted that the molecular weight of OSML could influence the turbidity of the suspension dramatically. The settling velocity of the flocs was increased, and the sediment compactness was reduced as the flocs enlarged. The charge neutralization and patching mechanisms were estimated to be dominant for coagulating the particles.