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A dynamic electrochemical technique was used for desulfurization of thiophene-containing solutions. First, adsorption of thiophene from an aqueous solution onto a platinum electrode surface and electrooxidative behavior of thiophene were studied using a cyclic voltammetry technique, and then, a square wave potentiometry method was utilized to electrochemically desulfurize the aqueous thiophene solution and a thiophene-containing model fuel. Results indicated that, for thiophene molecules, the best adsorption potential is 0.2 V and the maximum electrooxidation rate occurs at 1.1 V. Also, the optimal square wave frequency was found as 50 Hz. Ion chromatographic measurement of sulfate ion concentration revealed that reaction conversion was 100% in the electrooxidative desulfurization of aqueous thiophene solution. The high desulfurization efficiency can be attributed to excellent electrocatalytic activity of the platinum electrode and performing experiments at the best operating conditions. On the basis of gas chromatographically quantitated thiophene concentration in the hydrocarbon phase, desulfurization reactions reached a conversion of about 88% during electrooxidative desulfurization of a model fuel/aqueous electrolyte emulsion. The lower desulfurization efficiency can be attributed to addition of a mass transfer (from hydrocarbon to aqueous phase) resistance and lessening the overall thiophene concentration. Ion chromatographic analysis of the aqueous phase revealed that only 38% of thiophene molecules were completely oxidized to sulfate ions. Fourier transform infrared spectroscopy studies of the hydrocarbon and the aqueous phases showed that the remaining part of converted thiophene molecules were partially oxidized to a sulfone and an organic sulfate compound. Due to polarity of these components, which results in their aqueous phase solubility, no more steps were required to separate the products of desulfurization from the hydrocarbon phase. On the basis of the obtained results, electrochemical desulfurization can be proposed as an effective alternative for the commercial hydrodesulfurization processes.

The synthesis and characterization of a series of metal‐doped ZIF‐8 (metal=Ni, Co and Cu) has been introduced to gain the highly efficient adsorption of dibenzothiophene (DBT) in liquid phase. Under 150 ml DBT/iso‐octane, 100–1700 ppm, and 25–85 °C, the excellent efficiency and reusability in DBT removal was achieved and fitted better with the pseudo‐first order reaction. The maximum adsorption of 191.84 mg S/g for Ni/ZIF‐8 and two steps for intraparticle diffusion study contrary to Cu‐ and Co‐ZIF‐8 suggested the presence of Ni‐HMeIM clusters in ZIF‐8 cavities. Comparing the performance of prepared adsorbents, the order of qmax and PC was the same, i. e. PC Ni/ZIF‐8> PC Cu/ZIF‐8>PC Co/ZIF‐8>PC ZIF‐8 and qmax (Ni/ZIF‐8)> qmax (Cu/ZIF‐8)> qmax (Co/ZIF‐8)> qmax (ZIF‐8) for both 10% and 100% BT. The prepared adsorbents had the FoMs ranging from 0.05‐0.07 that compared to other adsorbents showed the beneficial use for large scale desulfurization process. The endothermic behavior and a homogeneous adsorption was then indicated through thermodynamic and equilibrium studies.

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Controlling characteristics of synthesized pseudoboehmite nanoparticles by means of parameters governing the neutralization process. Proposing formation mechanism of pseudoboehmite in three main stages: nucleation, aggregation and assembly.

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