Solar irradiated and metallurgical waste catalyzed conversion of waste cooking oil to biodiesel

This research article is based on the novel conversion of waste cooking oil (WCO) to biodiesel using heterogeneous waste catalysts from Pakistan steel industry, solar energy and conventional heating. The catalysts were analyzed by using the powerful tool of techniques including flame atomic absorption spectroscopy (FAAS), powder x-ray diffraction (XRD), IR spectroscopy and scanning electron microscopy (SEM). The sample of waste cooking oil was subjected to pretreatment through sedimentation, degumming and filtration. The process of transesterification of WCO was carried out with methanol and bioethanol by using industrial waste catalysts under the influence of conventional heating, solar ordinary heating and solar concentrated heating. Sixteen catalysts were tested for biodiesel production, however only five catalysts namely green dust obtained from refractory brick (A), grayish black dust obtained from glass furnace of line breaking material (B), white solid dust obtained from slab of casting floor (C), brown waste produced from broken lining of converter (D) and gray waste dust obtained from converter solid slag (E) were found to be active for the production of biodiesel. The flame atomic absorption (FAAS) and XRD techniques showed the existence of various concentrations of CaO, MgO and ZnO as major oxides along with the traces of some other metal oxides. However, the order of major oxides concentration was found to be as CaO > MgO > ZnO. The basicity test, qualitative determination of metal ions and quantitative determination of calcium was also determined. Bioethanol was produced on large scale from bagasse and used for the transesterification of WCO. Methanol was found to be slightly reactive than bioethanol that was evident from the yield of biodiesel. The solar energy was compared with the conventional heat which is renewable, green and costless. Biodiesel was analyzed by ASTM standards including acid value, saponification value, iodine value, cloud point, pour point, flash point and density which were found to be in agreement with the standard ASTM values. Development of biodiesel technology can play a vital role to mitigate global warming, energy crisis, environmental pollution etc.