Adsorption of lead from aqueous solution using Teak (Tectona grandis) sawdust

Sawdust, a wood waste was used to prepare activated carbon, and its adsorptive performance in removing Pb2+ from wastewater was investigated. Modification of Teak sawdust was carried out using orthophosphoric acid. Physicochemical and adsorptive parameters of activated sawdust (ASD) were examined using Scanning Electron Microscope, Fourier Transform Infra-red, and EDX respectively. SEM images of ASD revealed defined pores, adsorbing Pb2+ ions to its surface, while the spectra showed the presence of functional groups accountable for Pb2+ ions adsorption. Langmuir, Freundlich, Temkin, and D-R Isotherm models were deployed to study the experimental data. Langmuir isotherm (R-2 = 0.9891) described the data with an adsorption monolayer capacity of 112.4 mg/g at 303 K. The D-R isotherm model depicted the mean free energy ranging from 1.29 to 4.08 kJ/mol, suggesting physisorption adsorption. The pseudo-second-order kinetic model was best fitted for the sorption process with R-2 values between 0.9996 and 0.9999. Adsorption thermodynamics reflected that the process was endothermic and spontaneous. Therefore, the utilisation of an economical activated carbon modified from Teak (Tectona grandis) sawdust was efficient for lead uptake from wastewater.