Adsorption of Metals from FAME of Nigerian Spent Vegetable Oils Using Waste Printing Paper: Non-Food Option for Biodiesel to Safe Food Security and Environment (Part II)

Fatty acid methyl ester (FAME) from spent vegetable oils requires pre and or post-transesterification treatment to meet International norms for biodiesel. The present study assessed the potential of waste printing paper (WPP) as post-transesterification treatment for adsorption of metals from FAME obtained from Nigerian neat and spent vegetable oils (NSpVOs). The WPP adsorbent was prepared according to Moyib et al. (2017). The adsorption experiments for the removal of single metal ions were carried out using 10 mL FAME samples, 1.0 g WPP at a constant 25^oC, pH 6 for 60 min. At the end of the contact time, alkali metals in FAMEs were estimated according to EN 14108 and EN 14109 for Na and K, respectively and alkaline and heavy metals followed AOAC (2005). The results revealed WPP was able to reduce the metal content in the FAME to acceptable limit level and also, enhanced biofuel properties such as acid value (AV) and Conradson carbon (CC) but with loss of minute FAME. Cluster analysis distinguished FAMEs after and before WPP adsorption treatment. Part I and II of this study show feasibility for diversifying Nigerian spent vegetable oils as non-food option for production of biodiesel and achieve low carbon footprint. Also, WPP as locally available and cheap adsorbent showed good potential as post-transesterification treatment of FAME to desirable quality.