Adsorptive removal of dibenzothiophene from model fuel over activated carbon developed by KOH activation of pinecone: Equilibrium and kinetic studies

Abstract

Activated carbon (AC) was developed from pinecone using KOH as an activator to eliminate dibenzothiophene (DBT) from a synthetic model of gasoline fuel. The best sample was the AC prepared, employing a 1.5:1 KOH: feed impregnation ratio at 750°C for 1 h. Thus, it was tested in the adsorptive elimination of DBT from the fuel after being identified by X‐ray diffraction (XRD), field‐emission scanning electron microscopy (FESEM), energy dispersive X‐ray (EDX), N2 adsorption–desorption isotherms, pore volume distribution, Fourier transform infrared spectroscopy (FTIR), total basic and acid groups, and pHPZC. The as‐obtained AC exhibited a Brunauer–Emmett–Teller (BET) surface area of 478.89 m2/g with an average pore size of 2.0 nm, indicating its micropores structure. A removal performance of 97.90% was obtained using 0.30 g of AC at 20°C for 30 min, while the adsorptive capacity amounted to 34.38 mg/g as per the Langmuir isotherm. The as‐synthesized AC exhibited a good adsorptive performance for eliminating S compounds from commercial gasoline (42.11%) under the optimal experimental conditions, which increased to 88.16% with increasing the mass of AC implemented in the adsorption process. The adsorption of DBT through the fixed‐bed approach was also adopted, and the results at various flow rates of the effluent through fixed bed of the AC were close to that obtained via the batch‐adsorption system. The regenerated AC exhibited excellent adsorptive performance for DBT until 5 cycles of reuse, reflecting the effectiveness of the obtained AC. Finally, the Langmuir adsorption isotherm and pseudo‐second‐order kinetics model best described the DBT adsorption by the AC developed from pinecone.

Fabrication of Activated Carbon Derived from Glycerin Pitch for Desulfurization of Model Fuel Oil and Electrode Application

“…Two isotherm models, Langmuir and Freundlich, were plotted in Figure , with mathematical eqs and , respectively. 1 q e = 1 K L q m + C e q m where R L indicates adsorption favorability, K L is a constant to reflect the energy of adsorption and affinity of the binding sites (L/mg), and C 0 (mg/L) is the initial concentration of the analytes log 0.25em q e = log 0.25em K F + 1 n log 0.25em C e where q e (mg/g) is a number of analytes on the absorbent’s surface, n and K F (mg/g) are the constants to reflect the adsorption intensity and capacity, and C e is the concentration of DBT at equilibrium in solution (mg/L). Langmuir clarifies that the ADS of DBT occurs on homogeneous active surfaces of the adsorbent with uniform adsorption energy between adsorbates . Unlike Langmuir isotherm, the isotherm model by Freundlich isotherm is a heterogeneous adsorption process with the nonuniform distribution of heat of adsorption throughout the surfaces .…”

“…Langmuir clarifies that the ADS of DBT occurs on homogeneous active surfaces of the adsorbent with uniform adsorption energy between adsorbates. 45 Unlike Langmuir isotherm, the isotherm model by Freundlich isotherm is a heterogeneous adsorption process with the nonuniform distribution of heat of adsorption throughout the surfaces. 46 The related parameters of Langmuir (q m , K L , R L , and R 2 ) and Freundlich (K F , n and R 2 ) are listed in Table 4.…”