Analyzing the Amount of Metal in Glycerin from the Acid-Catalyzed Solvent Extraction Process Cooperating with a Rotary Evaporator

Abstract

Biodiesel can be used as a renewable energy in biodiesel production, crude glycerin is always a by-product. So, if we are able to increase the value of such crude glycerin, the cost of the biodiesel production process will be cheaper. Besides the percentage of glycerin purity, the percent of contaminated metal in the extracted glycerin is also important. If the extracted glycerin has a high percent of purity and a high percent of contaminated metal, the extracted glycerin cannot be used as a reactant in many industries. Therefore, the purpose of the research is to study the metal content of potassium (K), sodium (Na), iron (Fe) and lead (Pb) in crude glycerin before and after the extraction process using 8 M sulfuric acid. and 8 M phosphoric acid in combination with a rotary evaporator.

From the result, crude glycerin, a by-product of biodiesel production from using oil, contained potassium (K) 3.2%, sodium (Na) 0.02%, iron (Fe) 29.4 mg/kg and lead (Pb) less than 2.5 mg/kg According to the research results, the extracted glycerin by using sulfuric acid 8M had 89.7 ± 0.01% of the purity with potassium (K) 0.03%, sodium (Na) 0.002%, iron (Fe) 2.8 mg/kg and lead (Pb) less than 2.0 mg/kg while the extracted glycerin by using phosphoric acid 8 M had 87.7 ± 0.01% of the purity with potassium (K) 0.04%, sodium (Na) 0.004%, iron (Fe) less than 2.5 mg/kg and lead (Pb) less than 2.0 mg/kg, respectively. The amount of contaminated metal had been reduced significantly and the number of heavy metals is in accordance under the standards of the Ministry of Industry. Therefore, the extraction of glycerin by this method will help to reduce the cost of biodiesel production and encourage communities to be more interested in biodiesel production which will make the energy sustainable in the community and the nation.