Characteristics of chemical modified activated carbons from bamboo scaffolding

In this study, bamboo scaffolding was used to produce activated carbon by carbonization at 600 °C and 900 °C with the purge of nitrogen. The 600 °C char was then further modified chemically by acids and alkalis by reflux for 6 hours. The produced chars were then characterized by nitrogen adsorption isotherm, He pyncometry, pH, elemental analysis and Boehm titration. For most of the chemically modified carbons, the micropore surface areas and volumes have increased compared with the 600 °C char, while the mesopore surface areas and volumes slightly decreased, which may have been due to the dissolving of some of the permeated inorganic matter and oxidizing deposited carbon that blocks the pore openings. For the acidic modified carbons, larger amounts of acidic groups were present in the carbons after being activated by phosphoric acid, phosphoric acid further treated with 2 mol·L ^-1 nitric acid, and calcium hydroxide. Although carbon treated with 2 mol·L ^-1 and 5 mol·L ^-1 nitric acid also produced high acidity, the surface areas and pore volumes were relatively low, due to the destruction of pores by nitric acid oxidation. The reduction of porosity may impair the adsorption capacity.