The utilization silica from oil fly ash as a raw material for paper filler

Abstract

Palm Oil Fly Ash (POFA) has been considered as a potential source of silica for paper filler. The objective of this work is to prepare a filler from the Palm Oil Fly Ash (POFA) to reduce disposal and waste problem. The extraction of silica from POFA can be carried out using solution of 5 M NaOH with ratio 1:5 (w/w, with respect to POFA), stirring speed of 600 rpm for 4 hours, resulting the 0.8770 M silica in Na2SiO3. The product is then reacted with Ca(OH)2 to produce paper filler (CaSiO3). The filler was characterized with Fourier Transform Infrared (FTIR), Scanning Electron Microscope-Energy Disperse X-Ray (SEM-EDX), X-ray Diffractometer (XRD) and Particle Size Analyzer (PSA). FTIR spectrum showed the formation of OH, C = O, Si-O-Ca and Si-O-Si functional groups, whereas the SEM-EDX analysis revealed the porous surface with the aggregation of needle-like morphology and contained five elements such as O (45,14%), Mg (0,85%), Si (15,65%), Ca (36,77%) and Al (1,59%). Meanwhile, XRD spectroscopy showed the presence of calcium silicate, calcite, vaterite, calcium hydroxide and quartz. Data from PSA analysis indicated that the filler has narrow particle size distribution compared with commercial fillers (GCC & PCC) and has small average particle size compared with PCC. The filler and the commercial counterparts were then applied as a paper simulation (hand sheet). Analysis of hand sheet showed that the presence of the synthetic filler in the hand sheet can improve brightness, opacity and bulk values, but slightly reduced in tensile and tearing index compared to that of PCC & GCC.