Production of Biodiesel from In-situ Transesterification and Activated Carbon from Coffee Residues

Abstract

Biodiesel helps reduce the emission of carbon monoxide, hydrocarbons and total particulate matters as compared with petroleum. Analysis biodiesel was prepared using four different concentration sulphuric acid, H2SO4 that acts as catalyst. In-situ transesterification and determination of biodiesel production were performed using gas chromatography–flame ionization detector (GC-FID) and gas chromatography-mass spectrometer (GC-MS) and nuclear magnetic resonance spectroscopy (1H NMR). Increased percentage concentrations of H2SO4 impregnation with spent coffee ground (SCG) made a significant impact on the biodiesel yield. The percentage conversion of biodiesel for 5%. 10%, 15% and 20% wt. H2SO4 calculated about 13.66%, 36.87%, 62.27% and 81.43% respectively. Then, the spent coffee ground’s (SCG) residue after the in-situ transesterification were collected to prepare activated carbon (AC) via one step activation with potassium hydroxide (KOH) and carbonized at 500°C for 2 hours. The prepared AC was further characterised using Fourier Transformed Infrared, FTIR and Thermogravimetric analysis, TGA and the results obtained for both raw SCG and AC/KOH were compared to study the advantages of AC over raw materials. For raw SCG obtained infrared spectrum showed many absorption bands present in the raw SCG whereas some absorption spectrums were missing in AC which indicates some of the functional groups were volatalised during carbonisation process. In addition to this, TGA was also performed for both the raw SCG and AC/KOH and were compared to investigate the phase transformation or weight loss occurred before and after the preparation of AC. Thus, it can be concluded that biodiesel can be prepared from SCG and the AC from residue of transesterification method can be further used for various industrial use such as purification, separation and recovery.