Efficacy of sargassum filipendula for the removal of PB2+, Cd2+ and Ni2+ ions from aqueous solution: A comparative study

Abstract

The efficacy of Sargassum filipendula was evaluated for removal of Pb2+, Cd2+ and Ni2+ ions. All experiments were performed in a batch system to study the effects of contact time, pH, biosorbent dose, initial metal ion concentration and temperature on the biosorption process. The optimum pH for Pb2+, Cd2+ and Ni2+ ions biosorption was found to be 5.0, 6.0 and 5.0, respectively. The equilibrium time for Pb2+ ions was 40 min and for Cd2+ and Ni2+ ions was 60 min. The equilibrium experimental data were analyzed using the six isotherm models and six kinetic models. The results were best fitted by the Bangham, pseudo-second order and pseudo-first order kinetic models for Pb2+, Cd2+ and Ni2+ ions biosorption, respectively. The biosorption isotherm was better explained by Fritz isotherm for Pb2+ ions and Redlich–Peterson isotherm for Cd2+ and Ni2+ ions biosorption. The uptake capacities of S. filipendula for Pb2+, Cd2+ and Ni2+ ions were obtained as 367.94, 103.5 and 34.3 mg/g, respectively. According to the thermodynamic parameters, the biosorption process was spontaneous, feasible and endothermic in nature. The result obtained has shown that the order of metal ion binding affinity for S. filipendula was Pb2+ > Cd2+ > Ni2+ ions.