Isotherm and Kinetic Study of Engine Oil Adsorption on to Crushed Chicken Feathers

Adsorption of engine oil using chemically activated chicken feathers was investigated with the aim of evaluating the efficiency, kinetics, and isotherm behaviour. Batch adsorption experiments were conducted using varying contact times (10–50 minutes) and adsorbent dosages (10 g and 20 g). The adsorption performance was evaluated based on percentage of adsorption capacity, while equilibrium data were analysed using Langmuir, Freundlich, and Temkin isotherm models. Results showed that adsorption efficiency increased with both contact time and adsorbent dosage. At 10 g dosage, efficiency increased from 44% to 76%, while at 20 g dosage, efficiency rose from 56% to a maximum of 98% at 50 minutes, indicating that higher adsorbent mass enhances oil removal due to increased availability of active sites. Isotherm analysis revealed that the Langmuir model provided the best fit (R² = 0.9048), suggesting monolayer adsorption on a relatively homogeneous surface with a maximum adsorption capacity (Qₘₐₓ) of 138.888 mg/g. The Temkin model showed moderate agreement (R² = 0.7064), indicating decreasing adsorption heat with surface coverage, while the Freundlich model exhibited poor fit (R² = 0.5123), suggesting that multilayer adsorption was not dominant. The results demonstrate that adsorption is primarily governed by physisorption mechanisms involving hydrophobic interactions and surface entrapment within the keratin structure of the feathers. Increased dosage significantly improved performance, while contact time influenced the transition from rapid surface adsorption to diffusion-controlled uptake. This study demonstrates that chemically activated chicken feathers are an effective, sustainable, and low-cost adsorbent for engine oil removal, exhibiting high adsorption efficiency and strong conformity to the Langmuir isotherm, highlighting their potential application in wastewater treatment and oil pollution remediation.