Kinetics, equilibrium and mechanisms of Ni (II) and Pb (II) ion biosorption using biosorbent mixture of rhizophora apiculate sp. and elaeis guineensis sp.

Abstract

The existence of metal ions in water supply has become a severe issue and created an awareness of the important of finding the significant methods for the removal of heavy metals (HM). In this study, the biosorbent used are Oil Palm Mesocarp Fibe (OPMF) (Elaeis guineensis sp.) and Mangrove Bark (Rhizophora apiculate sp.). These biosorbents are mixed to form the biosorbent mixture (BM) to enhance the biosorption performance towards Ni (II) and Pb (II) ions. Four parameters applied to investigate the biosorption performance, i.e. reaction time, ratio/dosage, initial concentration and pH values. The biosorption performance for Pb (II) (90%, 5.7mg/g) was higher than Ni (II) (55%, 3.9mg/g). Five kinetic models were exercised to investigate the kinetic mechanisms namely pseudo-first and second-order, Bangham's theory, intra-particles diffusion and Elovich equation. The isotherm models i.e Langmuir, Freundlich, Dubinin-Radushkevich and Temkin Isotherm are exercised to analyse the equilibrium biosorption data. Overall, the pseudo-second-order discovered to act as biosorption kinetics for both Ni (II) and Pb (II) ions. The equilibrium biosorption data of Pb (II) follows Temkin Isotherm, and the Ni (II) supported by the Freundlich Isotherm.