In refi ning palm oil, bleaching earth is used to remove colour, phospholipids, oxidized products, metals and residual gums from the oil. It also absorbs approximately 0.5% by weight of the oil in the process. Spent bleaching earth (SBE) is usually disposed of in landfi lls, normally, paid for by the refi nery. Due to the increasingly high cost of disposal, it is desirable to use the material instead. The oil in SBE (Figure 1) can be recovered via solvent or supercritical fl uid extraction (SC-CO2 ) with a yield of up to 30% by weight of the SBE. The SBE generated annually by Malaysian palm oil refi neries is estimated to be approximately 120 000 t. The potential oil that can be recovered is estimated to be approximately 36 000 t. The recovered oil would have high free obtained was (1) subjected to transesterifi cation to convert to methyl esters; (2) pre-treated and used for formulating a bio-lubricant.

Main Research: Dr. Loh Soh Kheang