PHYSICO-CHEMICAL PROPERTIES OF PALM OIL FUEL ASH AS COMPOSITE SORBENT IN KAOLIN LANDFILL LINER SYSTEM

This paper presents information on the physicochemical properties of palm oil fuel ash (POFA) a biomass residue, while justifying its use as composite sorbent when pre-mixed with kaolin, for the purpose of designing sanitary landfill liner. Physical analysis conducted includes particle size distribution and density tests for the ground ash. Chemical tests include Energy Dispersive X-Ray diffractometer (XRD), Energy Dispersive X-ray Fluorescence (EDXRF). Other chemical tests conducted are the specific surface area (SSA); using Particle size analyzer (PSA), scanned electron microscope (SEM), mass loss on ignition (LOI), at 440 ± 25 °C, for a period of 4 h. The pHvalue for POFA- aqueous environment was also determined. Quantity of Silica oxide (SiO2) present in the ground ash was found to be 52.35 %. The summation of SiO2, Al2O3, and Fe2O3 present in the POFA was approximated to 72 %, while the inherited calcium oxide (CaO-lime) was approximated to 12 %. Both percentages classify the POFA as a Class C fly ash. Exchangeable cations detected include Na2+, K^2+, Ca^2+ and Mg^2+. Morphological analysis conducted also shows that the ground POFA was amorphous in structure. From these properties inferences were anticipated on the expected chemical reactions of the kaolin-POFA mixture for the design of composite sanitary landfill liner. The novel material is hoped to provide a more efficient chemical trapping mechanism of toxic heavy metal ions released from solid wastes that are been dumped in landfills. Conclusively, it is anticipated that POFA a bio-sorbent may be suitably used as composite sorbent for improvement on kaolin designed as lower component of engineered sanitary landfill liner.