Biosorption of Ni(II) from aqueous solutions by Litchi chinensis seeds

► The potential of L. chinensis seeds for biosorption of Ni(II) was investigated. ► Langmuir model provided best correlation of experimental equilibrium data. ► The pseudo-second-order model best described the biosorption kinetics. ► The biosorption process of Ni(II) was endothermic and non-spontaneous. ► Results recommend this material as a potentially low-cost and effective sorbent.