Synthesis and Characterization of Spent Bleaching Clay-based Geopolymer: An Effort towards Palm Oil Industry Waste...

Spent bleaching clay (SBC) is a problematic waste from the palm oil industry with worldwide availability. In this study, geopolymer was synthesized from SBC, a kind of aluminosilicate material with an alkaline activator solution that is made up of sodium hydroxide and sodium silicate. Calcium silicate (CS), which is a by-product of the silicates removal from wastewater, was also added to the formulation. The geopolymer mixture paste was cured in an oven at 80 °C for 24 h and at room temperature for 7 days. The characterizations were carried out using FTIR spectroscopy, SEM/EDX, TGA, BET, and XRD. The SEM images showed an aggregate of aluminosilicate material is formed with some unreacted particles on the surface of the geopolymer. The TGA results show that the geopolymers decomposed at a higher temperature than SBC, demonstrating its heat resistance properties. The BET results showed the addition of CS formed a denser geopolymer with a total pore volume of 0.0636 cm³ /g.