Fossil fuels’ pollution and their non-renewability have motivated the search for alternative fuels. Some common example of seed oils are sunflower oil, date seed oil, soy bean oil. For instance, soy methyl and soy-based biodiesel are the main biodiesel. Biodiesel is a clean diesel fuel that can be produced through transesterification reaction. Recycled cooking oil, on the other hand, is one of the inexpensive, easily available sources for producing biodiesel. This article is aimed at production of biodiesel via trans-esterification method, Nano CaO synthesis using sol-gel method, and Nano MgO synthesis using sol-gel self-combustion. Two catalysts’ combination affecting the reaction’s efficacy was also discussed. Optimum conditions for the reaction in the presence of Nano CaO are 1.5 % weight fracture, 1:7 alcohol to oil proportion and 6 h in which biodiesel and glycerin (the byproduct) are produced. Moreover, the optimum conditions for this reaction in the presence of Nano CaO and Nano MgO mixture are 3 % weight fracture (0.7 g of Nano CaO and 0.5 g of Nano MgO), 1:7 alcohols to oil proportion and 6 h. Nano MgO is not capable of catalyzing the transesterification by itself, because it has a much weaker basic affinity but when used with Nano CaO due to its surface structure, the basic properties increase and it becomes a proper base for the catalyst so that CaO contact surface increases and transesterification reaction yield significantly increases as well. This study investigates the repeatability of transesterification reaction in the presence of these Nano catalysts as well.

Biodiesel production was made by the electrolysis of the waste cooking oil by using heterogeneous nano catalysts. Seven types of catalysts (MgO-KOH, MgO-NaOH, CaO-KOH, CaO-NaOH, and combination of them) were prepared and the effects of different catalyst amount were investigated. The results showed that using MgO-NaOH nano catalyst weight ratios to oil (3 and 5) produced biodiesel with 94–98% yield. The prepared biodiesel was in accordance with the world standard of fuel ASTM and EN. Scanning electron microscopy images and X-Ray diffraction patterns of the prepared nano catalyst showed that the average mean crystal size of the particles was 66.77 nm.

In this study, we investigated the synthesis of silver nanoparticles using Peganum harmala water extract at ambient temperature. The Ag nanoparticles (AgNPs) were characterized by ultraviolet–visible spectroscopy (UV–vis), Fourier transform infrared spectroscopy (FT–IR), powder X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and transmission electron microscopy (TEM). The average particle size of the silver nanoparticles was about 23 nm. Inhibitory activity of the synthesized AgNPs was tested against human pathogens like Escherichia coli and Staphylococcus aureus. The results indicated that the AgNPs showed moderate inhibitory actions, demonstrating its antibacterial value against pathogenic diseases. GRAPHICAL ABSTRACT