SUDAD ASAAD ALKINANI*, AFRODET A. SALEH AND A. M. ATHBI
Department of Ecology, College of Science, University of Basrah , Basra, Iraq
*(e-mail: sudad.mutashar@uobasrah.edu.iq; Mobile: 00960 79013 15232)
(Received: April 12, 2023; Accepted: May 25, 2023)
ABSTRACT
Biodiesel is a promising renewable fuel that can be used as an alternative to fossil fuels. In this study,
biodiesel was produced from Zygnema carinthiacum green algae by extracting oil and then converting the oil in two steps (esterification and transesterification) using two types of catalysts: calcium oxide (CaO) produced from eggshells and calcium oxide impregnated with silver nanoparticles (CaOAgNPs) produced from the same algae Z. carinthiacum. The properties of algal oil and biodiesel produced were investigated using Gas Chromatography-Mass Spectrometry (GC-MS) and Fourier Transform Infrared Spectroscopy (FTIR). The AgNPs were synthesized and characterized using a UV-visible Spectrophotometer, (FTIR), X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM), which confirmed the synthesis of mostly spherical nanoparticles with sizes ranging from 19.92-52.38 nm. Fuel properties, including density, kinematic viscosity, cloud point, pour point, and acid value were determined and their values were 0.877 g/cm3, 4.71 mm2/s, 3°C,-4°C, 0. 34 mg KOH/g, respectively, for biodiesel produced by used CaO catalyst, as for the biodiesel produced using CaOAgNPs catalyst their values were 0.867 g/cm3, 4.12 mm2/s, -2°C,
-7°C, 0.46 mg KOH/g., respectively. The results also revealed that a biodiesel yield of approximately 78% was obtained using CaO and nearly 80% using CaOAgNPs. In conclusion, the production of biodiesel from Z. carinthiacum oil as an alternative feedstock using an AgNPs-impregnated CaO catalyst made from eggshell waste was discovered to be an environmentally-friendly and promising technique.
Key words : Biodiesel, transesterification, eggshells catalyst, Zygnema, calcination, AgNPs green synthesis