Preparation and application of EDTA-functionalized underutilized Adansonia digitata seed for removal of Cu(II) from aqueous solution

The application of ethylenediaminetetraacetic acid surface functionalized Adansonia digitata seed (EAD) from Nigeria was evaluated as a possible means of treating Cu contaminated water. The seed of A. digitata (AD) and EAD were characterized using Fourier Transform Infrared spectrometer, Thermogravimetric analysis, X-ray Diffraction analysis, Scanning Electron Microscopy, Energy Dispersive Spectroscopy, Particle Size Dispersion (PSD), zeta potential and elemental analysis (CHNS/O analyzer). The kinetics studies revealed the adsorption of Cu(II) onto AD and EAD to follow pseudo-second order model which fitted well for Temkin and Freundlich isotherm. The adsorption was controlled by both intra-particle diffusion and liquid film diffusion with adsorption capacity of AD (33 mg g−1) higher than that of EAD (27 mg g−1). The PSD of AD and EAD was found to be mono-modal, the ΔGo values increased as the temperature increased in EAD unlike AD where the value was reduced as temperature increased. The present work showed A. digitata seed as a potential resource for treating Cu contaminated water. The present work also reveals that it is important and necessary to pretreat plant sourced materials before being used for wastewater treatment.