Preparation and characterization of NaOH-activated carbons from phenolic resin

Abstract

Chemically (NaOH) activated carbons (CACs) from phenolic resin were prepared at temperatures from 600 to 800 °C in N₂. The effect of the NaOH/phenolic resin ratio and activation temperature on the BET surface area and carbon yield of the resulting carbons was investigated. The optimum NaOH/phenolic ratio is from 1.5 to 2.0 to produce high surface area and carbon yield at 600 °C. With increasing activation temperature from 600 °C to 800 °C, the BET surface area increased but the carbon yield decreased. NaOH-activated carbons have a higher concentration of narrow micropores (<10 Å) and a lower concentration of mesopores than a commercially available activated carbon, GAC-F400. Lower temperature (600 °C) NaOH-activated CAC-600 has a higher concentration of narrow micropores (<7 Å) than an 800 °C NaOH-activated carbon, CAC-800. Much higher adsorption capacity for CO₂ and H₂ is obtained with a NaOH-activated carbon as compared to GAC-F400. A higher content of oxygen-containing groups but without any hydrogen in CAC-600 is observed by EA and XPS. The adsorption isotherms of methyl tert-butyl ether (MTBE) show that CAC-800 has a higher adsorption capacity than GAC-F400 and CAC-600.