Nonlinear modelisation of heavy metal removal from aqueous solution using Ulva lactuca algae

Abstract

After extensive analysis, Ulva lactuca dried algae, collected from the Monastir coastal zone, was proven to be successful as an adsorbent for the removal of certain inorganic pollutants. The main objective of this study was the nonlinear modeling of heavy metal removal from an aqueous solution, using a freely available and well analyzed biomaterial, as well as the evaluation of its efficacy on various metal ion sorptions. Although relatively low specific surface area, compared to more conventional adsorbents, the selected biomaterial displays very interesting retention capacities when used with aqueous inorganic pollutants. The pseudo, first and second-order kinetic models were used to investigate the kinetic retention mechanism. Assuming the nonlinear form, the results indicate that the retention mechanism is diffusion controlled. Concerning the heavy metal uptake capacity, it was found that the selected biomaterial has a retention capacity of 67 mg g(-1) of Ni(II), 112 mg g(-1) of Cu(II), 127 mg g(-1) of Cd(II) and 230 mg g(-1) of Pb(II).