Thermodynamics and Adsorption Efficiencies of Maize Cob and Sawdust for the Remediation of Toxic Metals from Wastewater

摘要

The thermodynamics andsorption efficiencies for the remediation of Cr, Ni and Cd from their aqueoussolutions using Maize Cob (MC) and Sawdust (SD) in a batch system are reported.Efficiencies were judged based on parameters such as sorbent weight, initialadsorbate loading concentration, pH and surface area. Shimadzu AA650 Double BeamAtomic Absorption/Flame spectrophotometer was employed to study concentrationdifferences before and after the adsorption process. Parameters such as ΔH, ΔSand ΔG were determined. On MC, ΔH varied as 1466.59, 1271.21 and 1347.70kJmol-1 for Cr, Ni and Cd respectively. While on SD it varied as -566.85, 256.32 and888.77kJmol-1respectively for the same order of metal ions. The three ions were found to bechemisorbed onto MC, while on SD Cr and Ni were physisorbed and Cd remainschemisorbed as suggested by Freundlich isotherm.