Kinetics and equilibrium modelling of lead uptake by algae Gelidium and algal waste from agar extraction industry

The adsorptive behaviour of biosorbent particles was modelled using a batch mass transfer kinetic model, which successfully predicts Pb(II) concentration profiles at different initial lead concentration and pH, and provides significant insights on the biosorbents performance. Average values of homogeneous diffusivity, Dh, are 3.6 × 10−8; 6.1 × 10−8 and 2.4 × 10−8 cm2 s−1, respectively, for Gelidium, algal waste and composite material. The concentration of lead inside biosorbent particles follows a parabolic profile that becomes linear near equilibrium.