Biosorption of lead (II) ions on Sargassum ilicifolium: Application of response surface methodology

•Brown macroalga Sargassum ilicifolium is an excellent alternative for removal of Pb(II).•This method was simple, low-cost and enhanced the Pb(II) sorption.•Response surface methodology approach was used to optimize the process variables.•Effect of pH, contact time, initial metal and alga concentrations were investigated.•Kinetic and thermodynamic of biosorption were studied.

In this study, the biosorption of lead (II) ions on Sargassum ilicifolium, brown seaweed, was investigated in a batch system. The effects of operating parameters such as initial pH, initial metal ion concentration, and biosorbent concentration on the lead (II) biosorption were studied using response surface methodology (RSM). The optimum biosorption conditions were determined as initial pH 3.7, biosorbent concentration 0.2 g l−1, and initial lead (II) ion concentration 200 mg l−1. The maximum uptake capacity of S. ilicifolium for lead (II) ions was found to be 195 ± 3.3 mg g−1 at optimum conditions. The nature of biomass–metal ion interactions was evaluated by FTIR analysis. The equilibrium biosorption data fit very well with both Langmuir and Freundlich isotherm models. The biosorption performance of S. ilicifolium for lead (II) ions (qmax = 195 mg g−1) was significantly higher than the Pb(II) biosorption performance reported for other biosorbents. The abundant and economic biomass S. ilicifolium could be used for removal of Pb(II) from wastewater.