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

Abstract

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 250C, 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+, K2+,
Ca2+ and Mg2+. 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.