Adsorption of crude oil from aqueous solution by hydrogel of chitosan based polyacrylamide prepared by radiation induced graft polymerization

The adsorption of crude oil (initial concentration 0.5–30 g/L) from aqueous solution using hydrogel of chitosan based polyacrylamide (PAM) prepared by radiation induced graft polymerization has been investigated. The prepared hydrogel was characterized by FTIR and SEM micrographs. The experiments were carried out as a function of different initial concentrations of oil residue, acrylamide concentration, contact time and pH to determine the optimum condition for the adsorption of residue oil from aqueous solution and sea water. The results obtained showed that the hydrogel prepared at concentration of 40% acrylamide (AAm) and at a radiation dose of 5 kGy has high removal efficiency of crude oil 2.3 g/g at pH 3. Equilibrium studies have been carried out to determine the capacity of the hydrogel for adsorption of crude oil, Langmuir and Freundlich adsorption models were applied to describe the experimental isotherms and isotherms constants. Equilibrium data were found to fit very well with both Freundlich and Langmuir models. Also the adsorption of oil onto the hydrogel behaves as a pseudo-second-order kinetic models rather than the pseudo-first-order kinetic model.