Desulphurisation of liquid fuel using adsorption onto bio-based activated carbon modified with chitosan and Fe ions

Removal of sulphur and sulphur compounds from liquid fuel is one of the most critical issues in the environment and energy field due to its widespread use and destructive effects. The aim of this research is the use of a bio-based activated carbon modified with chitosan and Fe ions (AC/Fe/CH) to remove Dibenzothiophene (DBT) from iso-octane as fuel. The properties of this adsorbent were identified using BET, EDX-SEM, and FTIR analyses. The effect of operating parameters including initial concentration (C), adsorbent amount (m), and stirring speed (U) was optimised to reach maximum removal of DBT from iso-octane fuel using RSM methodology. The maximum removal percentage of DBT using AC/Fe/CH was 98.229%, and the optimal conditions were 0.05 g /25 mL of adsorbent, DBT concentration of 149 mg L−1, and stirring speed of 50 rpm. The improvement of adsorption ability is attributed to the modification and creation of iron cations and N+ ions onto the activated carbon surface. DBT is attracted by Fe cations adsorption centre via π-complexation and S-Fe bond and attracted by N+ adsorption centre via electrostatic forces. By analysing the kinetics data with various kinetics models, the result indicated that the pseudo-second-order kinetics model is consistent with the experimental data. The Langmuir model has higher compatibility than other models with the equilibrium data. The Modified activated carbon with chitosan and Fe has the maximum adsorption ability equal to 270 mg g−1. According to the obtained data, the prepared adsorbent (AC/Fe/CH) has the appropriate ability to separate DBT from liquid fuel.