Lead removal onto cross-linked low molecular weight chitosan pyruvic acid derivatives

•Synthesis and characterization of adsorbents.•Adsorption experiments were conducted.•CS8PA-GLA > CS11PA-GLA for the removal of lead.

Adsorption capacity of cross-linked low molecular weight chitosan pyruvic acid derivatives CSnPA-GLA (n = 8, 11) were examined by employing 23 factorial design method. Three (3) factors and two (2) levels of adsorbent dose (A) (0.05 and 0.1 g), adsorbent type (B) (CS8PA-GLA and CS11PA-GLA) and concentration of lead solution (C) (1 and 3 mg/L) were considered. From the statistical analysis, all the main parameters (A, B and C) and some interactions of the main parameters (AC and ABC) had influence on the adsorption process at 5% significance level. The adsorption process was greatly influenced by the adsorbent type (B). The adsorption equilibrium results correlated well with the Freundlich isotherm model. The adsorption kinetic data also correlated well with the pseudo second order. The thermodynamic studies also revealed that the nature of lead adsorption was spontaneous and endothermic. The findings suggest that CS8PA-GLA is better than CS11PA-GLA for lead sorption.