Optimization of mesoporous activated carbon from coconut shells by chemical activation with phosphoric acid

Abstract

Mesoporous activated carbons were prepared from coconut shells by the method of chemical activation with H3PO4. Effects of main influence factors on the yield and adsorption properties of activated carbon were studied via orthogonal experiments. Experimental results under the optimum conditions were as follows: the yield of the activated carbon was 36.90%; methylene blue adsorption was 21.5 mL/0.1 g; and the iodine number was 889.36 mg/g. The surface area of the activated carbon prepared was 891 m2/g, as determined by the BET method. Horvath-Kawazoe equations (H-K) and density functional theory (DFT) were introduced to analyze the porous structures of the activated carbon. It was shown that the activated carbon was mesoporous, with a total pore volume of 0.7233 mL/g, a micropore volume of 37.06%, a mesopore volume of 62.85%, and a macropore volume of 0.07%. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) studies demonstrated the results of the pore structure analysis.