Biosorption is a property of certain types of inactive, dead, microbial biomass to bind and concentrate metal ions from aqueous solutions. In the present study, the metal ions Cu(II), Cd(II), Pb(II) and Ni(II) removal potential of acacia leucocephala bark powder, fungus (T. versicolor) biomass and chitosan-abrus precatorius blended beads is investigated by kinetic, equilibrium and thermodynamic studies. The basic objective of the study is to contribute to the understanding and modeling of the equilibrium adsorption process. For this purpose, the effect of various factors affecting adsorption such as pH, contact time, biomass dosage, initial metal ion concentration and temperature is investigated. The experimental data are fitted to Lagergren-first-order and second-order, intraparticle diffusion kinetic models, and Langmuir and Freundlich isotherm models. The thermodynamic parameters, such as change in Gibbs free energy (?Go), entropy (?So), and enthalpy (?Ho) are...