A sustainable management of polycyclic aromatic hydrocarbons to synthesize microporous organic polymers for adsorptive desulphurization of fuels

Abstract

A sustainable management of carcinogenic polycyclic aromatic hydrocarbons (PAHs) to synthesize a series of high surface area (SABET of 563–1553 m2 g−1) microporous polymeric adsorbents is reported. The products with high yield (>90%) were obtained within only 30 min at a low temperature of 50 °C using a microwave-assisted approach with 400 W microwave power followed by 30 min of ageing by raising the temperature to 80 °C. The synthesized adsorbents are used for removing another category of carcinogenic pollutants i.e., polycyclic aromatic sulphur heterocycles (PASHs) from model and real fuels. Adsorptive desulphurization experiment in batch mode could reduce the sulphur from high concentrated model (100 ppm) and real (102 ppm) fuels to 8 ppm and 45 ppm respectively. Similarly, desulphurization of model and real fuels with ultralow sulphur concentrations of 10 and 9 ppm, respectively, reduced the final concentration of sulphur to 0.2 and 3 ppm, respectively. Adsorption isotherms, kinetics, and thermodynamic studies have been conducted using batch mode experiments. Adsorptive desulphurization using fixed bed column studies show the breakthrough capacities of 18.6 and 8.2 mgS g−1, for the same high concentrated model and real fuels, respectively. The breakthrough capacities of 1.1 and 0.6 mgS g−1 are estimated for the ultralow sulphur model and real fuels, respectively. The adsorption mechanism, based on the spectroscopic analysis (FTIR and XPS) demonstrates the role of π-π interactions between the adsorbate and adsorbent. The adsorptive desulphurization studies of model and real fuels from batch to fixed bed column mode would offer an in-depth understanding to demonstrate the lab-scale findings for industrial applications. Thus, the present sustainable strategy could manage two classes of carcinogenic petrochemical pollutants, PAHs and PASHs, simultaneously.