Keywords: activated carbon, phenol adsorption, rice husk, adsorbent functional groups, wastewater treatment, zinc chloride, phosphoric acid, kinetic modelling
Properties of activated carbon prepared from rice husk with chemical activation
The present work involves an investigation of the possible use of activated carbon developed from rice husk by chemical activation with zinc chloride (ZnCl2) and phosphoric acid (H3PO4) under different activation conditions for the removal of phenol from artificial wastewater. The physical and surface properties of the developed adsorbents were characterised using FTIR and SEM. A comparison between ZnCl2 and H3PO4 shows that the efficiency of phenol removal by H3PO4 activated carbon is generally lower than that of ZnCl2 activated carbon for both activation temperatures. After 24 hrs, removal efficiency of up to 90% could be achieved with 0.5 g ZnCl2 activated carbon, either prepared at 500°C or 600°C activation temperature. However, for 0.1g ZnCl2 activated carbon, an efficiency of 80% to 85% and 69% to 74% could be achieved at 500°C and 600°C activation temperatures, respectively. For H3PO4 activated carbon prepared at 500°C, the efficiency was 45% to 48% and 48% to 56% for 0.1 g and 0.5 g of adsorbent respectively. While for H3PO4 activated carbon prepared at 600°C, an efficiency of 41% to 45% and 43% to 51% could be achieved with 0.1 g and 0.5 g, respectively. The kinetics of phenol adsorption on both ZnCl2 and H3PO4 activated carbons were found to follow the pseudo–second–order kinetic model.