Department of Chemistry
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Item Desulfurization of Model Fuel Oil Using Modified Lignin@S-g-C3N4: Optimization via Response Surface Methodology(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2025) Saba Iqbal; CIIT/SP24-R06-014/LHR; Dr. Sadaf Ul Hassan; LHR TP 10020This work reports the oxidative desulfurization of dibenzothiophene in model fuel using Kraft Lignin doped S-graphitic carbon nitride (Fe@KL/S-g-C₃N₄), a newly synthesized and eco-friendly catalyst. Thus, the formation of the composite was confirmed using other characterization techniques such as Energy-Dispersive X-ray Spectroscopy (EDX), Raman Spectroscopy, UV-Visible Spectroscopy, X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). The result further showed that Kraft lignin (KL) was well adsorbed on to the S-g-C₃N₄ surface. New functional groups created through Kraft lignin adsorption increase surface coverage, add new active sites and improve S-g-C₃N₄ dispersion. The combined action inside the Fe@KL/S-g-C₃N₄ composite enhances its reactivity and also broadens the optical adsorption range. Optimizing the catalyst's effectiveness and assessing the impact of crucial variables on dibenzothiophene conversion. The following parameters were found to be ideal for maximal sulfur removal (98.37% conversion from 200 ppm): 42.5 °C, 0.3 g of catalyst, 32.5 minutes of reaction time, and 1 ml of H2O₂ as the oxidant. The quadratic model was shown to be very accurate (R2 = 0.9905), with a negligible lack of fit (p-value = 0.6671) when compared to the pure error, according to statistical analysis using ANOVA. The heterogeneous catalyst showed exceptional longevity by retaining both its structural integrity and its catalytic properties across five consecutive reuse cycles, proving to be a sustainable choice for desulfurization operations.Item Desulfurization of Model Fuel with Mxene-Polyoxometalate Based Catalyst: Optimized by Box Behnken Design(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2025) Kanwal Shaheen; CIIT/FA23-R06-012/LHR; Dr. Sadaf Ul Hassan; LHR TP10012Transportation fuels containing sulfur compounds are very dangerous to the environment and to health since when burnt they result in the generation of sulfur oxides. More stringent fuel regulations have necessitated the urgent need to have efficient and sustainable desulfurization technologies. The paper is concerned with the desulfurization of model fuel with an MXene-polyoxometalate (POM) based catalyst with process optimization being done by using Box-Behnken experimental design. The synthesis and characterization of a MXene-supported polyoxometalate catalyst was verified by the use of different physicochemical methods to establish the integrity of its structure, surface activity, and catalytic performance. The oxidative desulfurization of model fuel having typical sulfur compounds under mild reaction conditions was tested as catalystics. The most important operating parameters such as the dose of catalyst, oxidants to sulfur ratio, temperature of reaction, and reaction time were carefully explored. The Box Behnken design of Response Surface Methodology (RSM) was used to approximate and optimize the desulfurization reaction and reduce the amount of experimental experiments. The predicted and experimental results were found to have a strong correlation and the developed quadratic model was found to possess high significance and reliability as statistically determined. The synergistic outcome between MXene and polyoxometalate elements was observed as a great removal of sulfur rate under optimal reaction conditions. This is due to the high surface area, good electron transfer characteristics of MXene and the high oxidative ability of the polyoxometalate which have increased desulfurization performance. Also, the catalyst was well stabilized and could be used repeatedly in various cycles, which implies that it can be used practically. In general, the study indicates that the use of MXene polyoxometalate based catalysts and ix statistic optimization by Box Behnken design is a cost effective and eco-friendly method of deep desulfurization of fuels which can be useful in industrial desulfurization technology in futureItem Surface Etched Mixed Matrix Membrane for Desulfurization of Model Diesel Oil(Library Information Services COMSATS University Islamabad Lahore Campus, 2020-02-17) Sadaf Ahmad; FA18-R06-001; Dr. M. Shahid Nazir; LHR TP 5959Fuel counts in basic necessity of modern life. However, fuel consumption has been turned into severe danger to the environment as well as human life due to the presence of sulfur components in fuel. Therefore, it has become essentially important to achieve ultra-low sulfur fuel. For this purpose, desulfurization has been vastly undergoing by using various techniques in recent decades. Polyoxometalates (POMs) are polyatomic anions comprising transition metal oxyanions associated with bridged oxygen atoms resulting in closed three-dimensional assemblies. POMs and their hybrid materials (such as POM-based porphyrin and POM based metal-organic frameworks (MOFs)), have been mostly reported in multidisciplinary research fields as brilliant candidates due to their characteristics properties. Specifically, hybrids of POM and porphyrin (~ POM@Porphyrin = POMOF) are outstanding materials for intended applications which being inorganic filler further incorporate in mixed matrix membranes (MMMs). MMMs generally fabricated through incorporation of inorganic fillers in polymeric matrix, have achieved great attention in recent research progress due to multiple applications in gas storage, catalysis, sensing, wastewater treatment, and biomedicine. The main objective of the current study is to use POMOF as a catalyst in desulfurization. Therefore, three POMOFs were fabricated by varying ratios (1:1, 2:1, 3:1) of cationic and anionic species. Characterization analyses such as UV/Vis, FTIR, and TGA showed successful synthesis of these POMOFs. The efficiency of POMOFs followed an order as 3 (95.5%)> 2 (85.5%)> 1 (70.3%). Among these three POMOFs, 3 exhibited excellent catalytic property in desulfurization. Furthermore, the desulfurization process could be recycled for ten times without a significant decrease in catalytic efficiency. Interestingly, POMOFs successfully accomplished desulfurization of model diesel oil and showed excellent renewability. To the best of our knowledge, such kind of POMOFs with special surroundings and bi-functional active sites are not reported.