Use of chicken feathers as potential adsorbent for the reclamation of industrial lean methyl diethanolamine solutions

Sweetening units using methyl diethanolamine (MDEA) solvent are instrumental in removing hydrogen sulfide and carbon dioxide from natural gas. However, over time MDEA degrades and loses its scavenging efficiency due to the formation of heat-stable salts (HSS) that are hard to remove. Chicken feathers (CFs), a poultry waste by-product, are rich in functional groups that could help to remove HSS from alkanolamine solutions. CFs were characterized using XRD, SEM-EDX, TGA, DSC, and BET. FTIR spectroscopy analysis confirmed the presence of hydroxyl and amide groups that were responsible for the total organic acid (TOA) anions adsorption. The Freundlich model best fitted the equilibrium adsorption data with a maximum uptake capacity of 525 mg/g at 298 K. Kinetic analysis showed that the Pseudo-Second-Order model best fitted results with a rate constant of 0.0006 min⁻¹. The equilibrium thermodynamic study showed that the biosorption process was spontaneous. CFs exhibited good recyclability and high TOA uptake capacity even after five cycles using absolute ethanol as the eluent, maintaining 88% of the adsorption ability. The results demonstrated that CFs could be employed as a low-cost alternative to commercial activated carbon absorbents that are currently used to clean industrial lean MDEA aqueous solutions from their HSS contaminants.