Alginate macrobeads filled with porous activated carbon (PAC) treated using different types of chemical activating agents were prepared in this study. Rice husk ash (RHA) was treated using five types of chemicals, such as sodium hydroxide (NaOH), potassium hydroxide (KOH), zinc chloride (ZnCl2), hydrochloric acid (HCl) and citric acid, at a low temperature (~80°C) for 2 hours to produce PAC with high porosity and compared to the conventional process using furnace with a high processing temperature. A biopolymer, namely sodium alginate, was used to hold the PAC powder to produce an immobilized structure of PAC in macrobeads form. Adsorption of remazol red (RR) dye using macrobeads was measured using UV-spectrophotometer, while the morphology and composition of PAC were observed using scanning electron microscope (SEM) and energy dispersive X-ray (EDX), respectively. The functional groups of PAC were identified using attenuated total reflection Fourier transform infrared (ATR-FTIR). The results indicated that the alkali treated PAC successfully removed up to ~99% of the dye in 120 minutes, while the acid treated PAC could only remove ~30% the dye at the same time. This demonstrated that alkaline treatment produced PAC with higher porosity structure and the PAC produced using NaOH has high adsorption of RR dye.
