Using discarded oyster shells to obtain biodiesel

• De la Cruz-De la Cruz, Miguelina ^[1] ; De la cruz-Burelo, Patricia ^[1] ; Hernández-Núñez, Emanuel ^[2] ; Santiago-González, Ramón Eduardo ^[1] ; Valerio-Cárdenas, Cintya ^[1] ; Villegas-Cornelio, Víctor Manuel ^[1]
  1. [1] Universidad Popular de la Chontalpa. División Académica de Ciencias Básicas e Ingenierías
  2. [2] Centro de Investigación y de Estudios Avanzados del IPN-Unidad Mérida
• Localización: Agro Productividad, ISSN-e 2594-0252, Vol. 15, Nº. 1, 2022 (Ejemplar dedicado a: Enero), págs. 11-19
• Idioma: inglés
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• Resumen

  • ABSTR ACT Objective: To evaluate the CaO made from oyster shell (C. virginica) as a heterogeneous catalyst in the transesterification of edible vegetable oil used for the production of biodiesel.

    Design/methodology/approach: A completely randomized experimental design was used, which grouped 3 treatments with 3 repetitions, generating a total of 9 experimental units. The response variable was the performance of the transesterification reaction that was evaluated with 2%, 3% and 4% of CaO obtained from oyster shells. The density, kinematic viscosity, acidity, and conversion efficiency to methyl esters were determined by 1H NMR of the products of each treatment.

    Results: The treatment with 3% catalyst showed the highest reaction yield (92.2%) compared to the treatments with 2% (86.8%) and 4% catalyst (87.13%). The 1H NMR spectra confirmed the presence of methyl esters in the product of the three treatments. The treatment with 3% and 4% by weight of catalyst presented products with similar characteristics with acceptable values of density, viscosity and acid number in accordance with the ASTM D6751 and EN1421 standards.

    Study limitations/implications: A concentration of 2% by weight of CaO generates a conversion percentage far from the content of methyl esters established by the ASTM D6751 and EN14214 Standards (96.5%).

    Findings/conclusions: 1H NMR results indicate that the conversion efficiency to methyl esters is positively affected by the amount of catalyst. In the treatments with catalyst loading greater than 2%, the conversion to methyl esters increased significantly to values around 90%.