Adsorptive desulfurization of low sulfur diesel fuel using palladium containing mesoporous silica synthesized via a novel in-situ approach

In this work, a novel in-situ synthesis route was applied for preparation of an adsorbent, i.e. palladium containing MCM-41. At first, a hydrophobic palladium precursor was added to the ethanolic micellar solution followed by vacuum distillation of ethanol which decreases the hydrophobic characteristic of the solution. Distillation caused diffusion of hydrophobic palladium precursor into the hydrophobic core of the micelles. Then, tetraethyl orthosilicate was added to the above solution and the silicate spices arranged around the palladium containing micelles. The XRD, N2 physisorption and TEM studies revealed that 4 wt.% palladium loading was achieved without considerable loss of pore ordering. H2-TPR showed that the palladium nanoparticles were accessible for hydrogen molecules. Adsorptive desulfurization of low sulfur diesel fuel was then investigated using synthesized samples. The effect of three valuable parameters, i.e., temperature (25, 75, 150 and 200 °C), concentration of palladium (2, 4 and 5 wt.%) and feed flow rate (0.3 and 1 mL/min) were tested using a fixed-bed flowing device. The highest sulfur break through adsorption capacity and total sulfur adsorption capacity obtained at 200 °C, 0.3 mL/min of feed flow rate and 4 wt.% of palladium concentration were 1.67 and 2.35 mg sulfur/g adsorbent, respectively.