Adsorption and desorption kinetics of toxic organic and inorganic ions using an indigenous biomass: Terminalia ivorensis seed waste

Abstract

Environmental remediation has been a strategy employed by scientists to combat water pollution problems that have led to the scarcity of potable water. Hence, in this study, Terminalia ivorensis seed waste (TISW) was explored for the removal of Congo Red, Methylene Blue, Cadmium and Lead from aqueous solutions. Some experimental variables such as pH, biosorbent dose, initial solute ion concentration, agitation time and temperature were optimised. The surface microstructures of TISW were studied using proximate analysis, bulk density, specific surface area, pH of Point of Zero Charge, Fourier Transform Infra Red Spectroscopy, Thermogravimetric/Differential Thermal Analysis, Scanning Electron Microscopy and Energy Dispersive Analysis of X-ray. The maximum Langmuir monolayer saturation adsorption capacity, q_{{max_{L} }}, was obtained as 175.44 mg/g for the removal of Methylene Blue by TISW. Also, the q_{{max_{L} }} for CR, Cd(II) ion and Pb(II) ion were 85.47, 12.58 and 52.97 mg/g, respectively. Also, the pseudo-first-order constant, k_{{_{1} }}, and pseudo-second-order rate constant, k_{2}, are 0.008–0.026 min−1 and 0.012–0.417 mg g−1 min−1, respectively. Hence, TISW is recommended as a good adsorbent for the removal of both toxic industrial dyes and toxic metal ions from polluted water.