Citrus limetta Peel-Derived Catalyst for Sustainable Production of Biodiesel

Abstract

To produce biodiesel from oleic acid (OA), the effectiveness of sweet lemon ( Citrus limetta ) waste peels as an acidic catalyst in an esterification process is examined in the current work. A biowaste-derived sulfonated carbon-based catalyst is fabricated without high temperatures via a simple one-pot process. Several techniques are used to investigate the chemical components and morphology of the catalyst, including Fourier transform infrared spectroscopy (FTIR), powder X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), Brunauer–Emmett–Teller (BET), and N 2 adsorption–desorption. The biodiesel conversion is observed by gas chromatography–mass spectrometry (GC–MS), proton nuclear magnetic resonance 1 H NMR, and carbon nuclear magnetic resonance 13 C NMR. The excellent biodiesel conversion of 96% was obtained using optimized conditions, i.e., 1:20 of OA/MeOH, 5 wt % catalyst loading, 70 °C temperature, and 3 h. The catalyst shows 87% conversion in just 1 h, and the maximum conversion was found to be ≈96%. This high activity of the catalyst can be attributed to the presence of sulfonic groups and its porous nature. The formed catalyst shows excellent catalytic activity up to three cycles.

Microwave-assisted synthesis of biodiesel by a green carbon-based heterogeneous catalyst derived from areca nut husk by one-pot hydrothermal carbonization

“…The highest biodiesel production (96.4%) was obtained under the optimization process. The conversion yield was calculated by the area ratio of different esters, the results match with previous study 27 (Fig. S1 ).…”

“…FTIR spectrum is used to analyze weak or strong acidic groups, which act as noteworthy active sites for esterification reactions by synergistic effect. The high intensity of the 1028 cm –1 peak in the SANH18 catalyst corresponds to the symmetric stretching of –SO 3 H, indicating the formation of a sulfonated catalyst 27 . Our results show the successful sulfonation of biomass-based catalysts even at low temperatures.…”

“…The carbonaceous sheetlike frameworks were detected by TEM (Fig. 4d-f) in the SANH18 catalyst; however, their formation was incomplete 27 . TEM images show that carbonaceous materials exist in the aromatic sheets.…”

“…As water is also a byproduct of esterification reaction, so it reduces the activity by acid site contaminations. In the majority of the literature survey, this may be due to the deactivation of catalyst by leaching of SO 3 H groups 27 , 65 . EDS spectra (Fig.…”

Advances in biomass derived low-cost carbon catalyst for biodiesel production: preparation methods, reaction conditions, and mechanisms

“…Heterogeneous catalysts are extensively investigated due to ease of separation, recyclability, noncorrosiveness of instruments and no soap formation. 13,14 There are a variety of materials that may be used to make heterogeneous catalysts, such as biochar, biomass ash, waste shells, agriculture products and activated carbon. 15 Researchers from all around the world have recently been interested in biomass-derived heterogeneous catalysts.…”