Ultrasound-assisted adsorptive desulfurization of dibenzothiophene from model fuel on K2CO3-activated biochar

Abstract

A novel mesoporous activated biochar (ABC) was developed from an equal mix of date and olive stones and implemented in the ultrasound-assisted adsorptive desulfurization (USADS) of model gasoline (300 ppm DBT/n-hexane) and model kerosene (300 ppm DBT/cyclohexane). The biowaste blend was carbonized at 450 °C for 75 min at a 10 °C/min heating rate, followed by K₂CO₃-activation. The superior ABC was synthesized at 750 °C for 1 h using an impregnation ratio of 1:1 K₂CO₃: biochar. The BET surface area and average pore diameter of the resulting ABC were 1099.70 m²/g and 5.14 nm, respectively. The USADS of both models was achieved at relatively mild experimental conditions (0.20 g of the ABC 30 °C, 40 min, and 120 W US power). At these conditions, the USADS of model gasoline amounted to 97.32 % compared to 99.39 % for model kerosene. The USADS process of both models followed the Langmuir model of the adsorption isotherms and the pseudo-2nd-order kinetics model. The ABC was recoverable and effective until the 5th regeneration cycle and reused reasonably. The maximum USADS of real gasoline (88.12 %) was achieved using 1.0 g of the ABC at 30 °C for 120 min.