Application of converter slag as an effective and low-cost solid base catalyst for the transesterification process

ABSTRACT

Calcium oxide is a suitable and valuable catalyst for producing biodiesel. In this research, the feasibility of producing biodiesel from waste frying oil with a new environmentally friendly and low cost heterogeneous solid-base catalyst from waste slag was evaluated. The composition, texture, structure, and chemical characteristics of the converter slag were examined by thermogravimetric analysis (TGA), X-ray fluorescence (XRF), Brunauer–Emmett–Teller (BET), Field Emission Scanning Electron Microscopy (FE-SEM), and X-ray diffraction (XRD). Moreover, the catalyst reusability, reaction conditions, and the effects of catalyst preparation conditions were studied in this experiment. The converter slag was calcined at 1100°C for 8 hours. Gas chromatography (GC) was used to analyse and evaluate the produced biodiesel. The biodiesel characteristics were compared with the ASTM D 6751 standard. It was found that the maximum efficiency of using converter slag for producing biodiesel was 77.8 ± 1.5% under the reaction time 6 hours, catalyst amount 10 wt.%, and reaction conditions of methanol to oil molar ratio 15:1. The converter slag as a catalyst was recovered and reused for three cycles. This study demonstrated how a low-cost catalyst could be used in the production of a value-added product (i.e. biodiesel) from waste oil.

Graphical Abstract

KEYWORDS:

• Biodiesel
• calcium oxide
• heterogeneous catalyst
• steel industry slag
• transesterification
• waste frying oil

Acknowledgments

The authors are most grateful to the School of Health and Safety for financial support. The authors would also like to thank the biodiesel laboratory of Tarbiat Modaress University for their collaboration in this study and Esfahan Steel Company to provide steel slag for this research.

Author contribution

Najme Masihi (master student): Conceptualization, Methodology; Nadali Alavi: Conceptualization, Methodology, Supervision, Project administration; Mirzaman Zamanzadeh: Supervision, Writing - Review & Editing; Monire Majlessi Nasr: Conceptualization, Methodology, Supervision; Akbar Eslami: Methodology, Validation, Formal analysis, Investigation; Ali Zenouzi: Methodology, Validation, Formal analysis, Investigation; Ehsan Aghayani: Review & Editing, Investigation; Reza Bakhshoodeh: Writing - Original Draft, Writing - Review & Editing, Visualization;

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This research was funded by a grant number (11563.NO) for the fulfilment of a Master’s degree in the School of Health and Safety of Shahid Beheshti University of Medical Sciences.