Effect of Phosphoric Acid Modification on Characteristics of Rice Husk Activated Carbon

Activated carbon was produced from rice husk via thermal pretreatment preceding chemical modification with phosphoric acid. In order to study the effect of phosphoric acid modification, the characteristics of the activated carbon produced were determined before and after acid modification and subsequently compared. These characteristics include surface morphology, surface functional groups, surface area, average pore diameter and pore volume. Characterization results showed that modification of the thermally treated rice husk with phosphoric acid enhanced the surface area of the activated carbon from 12.47 to 102.4m2/g. The average pore diameter was also enhanced from 2.4 to 1.82nm. It also shows improvement in micropore volume from 0.0052 to 0.034cm3/g. SEM analysis confirmed the improvement in surface area and pore development resulting from the phosphoric acid modification while FTIR analysis revealed the existence of phosphorous-oxy-containing functional groups on the surface of the phosphoric acid modified activated carbon.