Physico-chemical Study of the Adsorption of Methyl Orange from Water by Biosorbent and Activated Carbon Based on Peanut Shells

The objective of this work is to study the elimination of Methyl Orange (MO) contained in wastewater, by adsorption on four different adsorbents, produced from peanut shells. To achieve this, the various adsorbents were first produced. The native biosorbent (BN) was obtained from drying, crushing and sieving the peanut shells. The activated biosorbent (BA) was obtained by chemical activation with ortho-phosphoric acid (H3PO4) 10% BN. The activated carbons (CA1 and CA2) were obtained by pyrolysis at 650°C of BN and BA, respectively. The four products were characterized adsorbents and experiments to determine the effects of pH, contact time, of their masses and the concentration of methyl orange in its removal by adsorption was carried out. The results show that the thermal activation of the BN has multiplied its surface area by 11, while chemical activation has multiplied by its specific surface 8. Both treatment (chemical and thermal) have also tripled the micropores of BN. All four adsorbents have a maximum adsorption capacity at pH6. At this pH, the amount of MO adsorbed decreases with increase in its concentration, regardless of the adsorbent used. Likewise, adsorption equilibrium is reached at 3 min on the four adsorbents. The pseudo second order model describes the adsorption kinetics of MO on the four adsorbents. Ultimately, CA1 is found to be the most effective in removing MO from wastewater.