OPTIMIZATION OF OIL PALM EMPTY FRUIT BUNCH GRAFTED POLYVINYL ALCOHOL HYDROGEL BY TAGUCHI METHOD AND INVESTIGATION OF ITS METAL IONS ADSORPTION

Heavy metal pollution in wastewater is one of the major environmental issues nowadays.
Hydrogel is a potential material to remove heavy metal ions through adsorption. The
purpose of this research is to optimize the Oil Palm Empty Fruit Bunch grafted
Polyvinyl Alcohol (OPEFB-g-PVA) hydrogel using Taguchi method at different
parameters based on the water absorption capacity. L9 orthogonal array from Taguchi
method was used to design the experiments based on the four parameters: reaction
grafting temperature, amount of initiator, amount of crosslinking agent and amount of
oil palm empty fruit bunch fiber. Then, experiment was conducted where OPEFB, crosslinking
agent - N,N'-Methylenebisacrylamide (NMBA) and initiator – ammonium
persulfate (APS) were added into PVA solution prepared according to the orthogonal
array. The grafted hydrogels were immersed in water containing 16ppm copper ions for
48 hours. The water absorption capacity and copper ion adsorption capacity were studied.
The maximum water absorption capacity obtained was 139.91%. The adsorption of
copper ion from the aqueous solution was accessed by atomic absorption spectrometer
(AAS). The highest copper ion adsorption capacity was 1.062 mg/g dry hydrogel.
However, it was found that the hydrogel with higher water absorption capacity has lower
copper ion adsorption capacity. Characterization of optimized OPEFB-g-PVA was
studied using Mercury Intrusion Porosimetry (MIP).