Photo-Esterification of Waste Cooking Oil Using a Novel Nanocatalyst TiO2 Impregnated with Empty Fruit Bunches Ash Heterogeneous Catalyst Siti Fadhilah Ibrahim(a), Norshahidatul Akmar Shohaimi(a*), Mohd Lokman Ibrahim(b), Zul Adlan Mohd Hir(a), Sufri Mastuli(b), Wan Nur Aini Wan Mokhtar(c)
a) Faculty of Applied Sciences, Universiti Teknologi MARA Pahang, 26400 Bandar Tun Abdul Razak Jengka, Pahang, Malaysia
b) School of Chemistry and Environment, Faculty of Applied Sciences, Universiti Teknologi MARA, 40450, Shah Alam, Selangor, Malaysia
c) Centre for Advanced Materials and Renewable Resources, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia
* Corresponding author: akmarshohaimi[at]uitm.edu.my
Abstract
The photo-esterification of waste cooking oil (WCO) with TiO2/EFBA photocatalyst as heterogeneous photo-catalyst has been investigated in this study. WCO is non edible oil with high free fatty acid (FFA) content, which need esterification then followed by transesterification to produce fatty acid methyl ester (FAME). The WCO were esterified with methanol by photocatalytic process and UV light irradiation as light sources. The TiO2/EFBA photocatalyst was synthesized using simple wet impregnation method. The samples were characterized by X-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS), Fourier Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscope (SEM) and Energy Dispersive Spectroscopy (EDX) analysis. Characterization results revealed that the bandgap of TiO2/EFBA successfully reduced from 3.0 EV to 2.88 EV that suitable in UV light irradiation and low energy needed in the process. The TiO2 semiconductor composite doped with empty fruit bunches ash (EFBA) showed a very high activity for FFAs photo-esterification. Experimental results showed that the optimum condition of photo-esterification with catalyst loading to oil 4 wt.%, 20:1 methanol to oil molar ratio and 2 h reaction time achieved the reduction of FFA content from 11.65 % to 2.04 % with FFA conversion of 83 %. FFA content was successfully reduced indicated that photo-catalytic esterification is viable option in order to produce FAME. Photo-esterification products were characterized by FTIR spectroscopy.
