Heterogeneous Catalysts from Metallic Oxides and Lignocellulosic Biomasses Ash for the Valorization of Feedstocks into Biodiesel: an Overview

Bekele, Demelash Tilahun; Shibeshi, Nurelegne Tefera; Reshad, Ali Shemsedin

doi:10.1007/s12155-022-10546-7

Cited by 4 publications

(25 citation statements)

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“…The WFO in this study is suspected of offering biodiesel with poor cold flow characteristics due to the higher percentage of saturated fatty acids . However, the presence of a higher saturated fatty acid composition is good for the oxidation stability of biodiesel . Therefore, to obtain biodiesel with better cold flow properties and oxidation stability, blending the WFO with feedstocks having higher unsaturated fatty acid compositions like UFO, RSO (Table ), and others may be recommended …”

Section: Results and Discussionmentioning

confidence: 99%

“…34 However, the presence of a higher saturated fatty acid composition is good for the oxidation stability of biodiesel. 1 Therefore, to obtain biodiesel with better cold flow properties and oxidation stability, blending the WFO with feedstocks having higher unsaturated fatty acid compositions like UFO, RSO (Table 1), and others may be recommended. 1 Proximate Analysis of CH, TS, and CH−TS.…”

Section: Methodsmentioning

confidence: 99%

“…Therefore, the synthesis or utilization of customized catalysts with better stability, activity, and selectivity is one of the things that the biodiesel production sector requests. The catalyst stability, activity, and selectivity rely on the nature of catalytic precursors and synthesis methods . The strength, concentration, and dispersion of the active sites including the catalyst texture also matter .…”

Section: Introductionmentioning

confidence: 99%

“…Lignocellulosic biomasses (LBs) are among the precursors that are renewable, relatively cheap, and environmentally friendly. Their calcination yields ash with mixed metallic carbonates and other compounds. , Thermal processing of LBs and their blend with chemical precursors also provides catalysts having blended oxides whose performance and stability are usually better than single oxides . However, alkali catalysts are only efficient for transesterification of feedstocks having low free fatty acids because of the soap formation reaction .…”

Section: Introductionmentioning

confidence: 99%

“…The combustion performance of biomasses can be tuned by techniques such as biomass blending and chemical modification . With this scenario, it may be possible to synthesize catalysts that have more activity and resistance to deactivation from a blend of LBs and chemicals . Thermal analyses, including thermogravimetric and differential thermal analysis techniques, can be employed to understand the combustion mechanism of biomasses and their derivatives …”

Section: Introductionmentioning

confidence: 99%

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Catalytic Performance Investigation of Alkali and Bifunctional Catalysts Derived from Lignocellulosic Biomasses for Biodiesel Synthesis from Waste Frying Oil

Bekele,

Shibeshi,

Reshad

2024

ACS Omega

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In this study, alkali and bifunctional catalysts were synthesized for waste frying oil methyl ester (WFOME) synthesis. Coffee husk (CH) and CH blended with Eragrostis tef straw (TS) (CH−TS) lignocellulosic biomasses (LBs) were utilized during the catalysts' synthesis. The alkali catalysts were CH and CH−TS ashes, both modified by KNO 3 impregnation. They are designated as C-45 and C-Mix, respectively. Zirconia (ZrO 2 ) promoted CH ash catalysts via precipitation followed by impregnation (Bic-PP) and in situ precipitation−impregnation (Bic-Dm) were the bifunctional ones. CH and CH−TS chars were the supporting frameworks during the catalysts' composite materials (CCMs) preparation. The combustion performance of LBs and CCMs was evaluated and associated with the catalysts' physicochemical properties. Using XRD, SEM, FTIR, alkalinity, TOF, and BET surface area analysis, catalysts were characterized. The combustion performance of the LBs was in the order of TS > CH−TS > CH. Among CCMs, the highest combustion performance was for CCM-Mix (KNO 3 /(CH−TS char)) and the lowest was for CCM-45 (KNO 3 / CH char). The C-Mix catalyst was a light green powder due to the reaction between inorganic components, whereas C-45 was dark gray due to the presence of unburned char. The CCMs for bifunctional catalysts had moderate combustion performance and yielded light gray powdered catalysts containing tetragonal ZrO 2 . The optimum WFOME yields were 98.08, 97, 92.69, and 93.05 wt % for C-Mix, C-45, Bic-Dm, and Bic-PP assisted WFO transesterification, respectively. The results were obtained at a reaction temperature of 65 °C, time of 1 h, and methanol to WFO molar ratio of 15:1 using catalyst amounts of 5 and 7 wt % for the alkali and bifunctional catalysts, respectively. The greatest moisture resistance was offered by the C-Mix catalyst. The best reusability was for the C-45 catalyst. Catalysts' deactivation modes include active site leaching and poisoning.

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Section: Results and Discussionmentioning

confidence: 99%