Production of Biodiesel using Calcined Brine Sludge Waste from Chor-Alkali Industry as a Heterogeneous Catalyst

Biodiesel is an environmentally friendly fuel, produced by a transesterification process using homogeneous catalyst which causes water pollution and cannot be recycled. The present study utilizes industrial brine sludge waste (IBSW) as a heterogeneous catalyst in the transesterification of waste cooking oil (WCO) into biodiesel. One variable at a time design was applied to optimize the transesterification process. The process variables were varied as follows: methanol to oil weight ratio (10–50 %), reaction time (0.5–2.5 h), reaction temperature (30–90 °C) and catalyst to oil weight ratio (0.84–4.2 %). The IBSW before and after calcination and the transesterification process was characterized using X-ray fluorescence (XRF), Fourier-transform infrared spectroscopy and scanning electron microscope (SEM). Biodiesel was produced at maximum yield of 95.51 wt% at reaction time, temperature methanol to oil weight ratio, and catalyst to oil weight ratio of 1 hour, 60 °C, 30 wt%, and 2.52 wt% respectively. The FTIR and SEM results confirms that before and after the transesterification process the modification of IBSW took place. Using the ideal process conditions, biodiesel was produced and vital fuel properties such as viscosity, density, pour point and flash point were measured and were found to be within the specification as per American Society for Testing and Material (ASTM) standards for biodiesel. The reusability of the IBSW catalyst was tested by recycling and it can be established that the catalyst can be utilized up to four times without affecting its catalytic activity.