Sustainable palm oil refining using pelletized and surface-modified oil palm boiler ash (OPBA) biosorbent

The palm oil industry has been one of the major economic contributors for Malaysia over the last decade. While contributing to the country's economic growth, the industry has inevitably produced a significant amount of waste materials which are harmful to the environment. Oil palm boiler ashes (OPBA) generated from boiler in mills are disposed in open landfills which are easily carried away by the wind. The disposed ash pollutes the air while spent earth, when left in landfills, produce a pungent odour. The present work investigated the possibility of refining palm oil with raw OPBA and pelletized OPBA as alternate bleaching adsorbents. The performance of different types OPBA (raw, enhanced and pelletized) was investigated to determine their bleaching efficiencies on carotenoid removal at various operating conditions. Crude palm oil samples were refined with these OPBA and compared with commercial bleaching earth to investigate the final refined oil colours. A final refined oil colour of 4.0R was obtained using 0.05 wt% of enhanced OPBA when bleached at 110 °C for 45 min under constant agitation (300 rpm) and subsequently deodorized at 265 °C for 1 h. This study has indicated that the use of enhanced OPBA which could achieve more than high removal of carotenoid could substitute commercial bleaching earths to produce a comparable final refined oil colour rating. The successful substitution of OPBA to replace the conventional bleaching earth in oil refining could significantly reduce the production cost. This is also a sustainable solution for the edible oil processing industries to mitigate the solid waste and contributes to a cleaner environment.