Safou (Dacryodes edulis) seeds applied to the removal of Bisphenol A in solution. Implication of surface antioxidant molecules on the chemical sorption of the endocrine disruptor

In this study, the fine fraction (< 100 μm) of safou seeds (Dacryodes edulis) was characterized and then applied to the removal of bisphenol A (BPA) form aqueous solution. The techniques used include scanning electron microscopy (SEM) which allowed access to the morphology of the material, Fourier transform infrared (FTIR) spectroscopy which revealed the chemical functions on its surface and BET technique from which its specific surface area was determined. Its behavior towards BPA was studied in batch mode under the effect of the variation of several parameters among which the contact time, the equilibrium pH, the adsorbent dosage and the adsorbate initial concentration. The optimal contact time and BPA adsorption pH were 25 min and pH 3, respectively. The pseudo-second order kinetic model and the Freundlich isotherm better fit the adsorption of BPA on safou seeds. The maximum adsorption capacity was 24.5 mg.g-1 obtained experimentally. The surface molecules of safou seeds, consisting predominantly of antioxidants (phenols, flavonoids, vitamin C) and fatty acids (palmitic, oleic and linoleic acid), effectively contribute to the chemical sorption of BPA by the formation of covalent bonds and hydrogen bonding. With so many functional molecules on its surface, safou seeds could be applied to the treatment of water containing bisphenol A.