Experimental investigation on the preparation of active carbon with cottonwood based on phosphoric acid activation method

Abstract

Active carbon was prepared experimentally by means of drying and crushing cottonwood via the phosphoric acid activation method. The effects of the activation temperature, impregnation ratio, phosphoric acid concentration, and activation time on the performance of the active carbon were analyzed. The optimum parameters of active carbon preparation, including the 60% concentration of the phosphoric acid, 1:4 impregnation ratio, 4 h activation time, and 500 °C activation temperature, were proposed. The features of the active carbon were analyzed with a scanning electron microscope and Fourier-transform infrared spectroscopy. The specific surface area was 1020 m2 · g-1, and the average pore diameter and the overall pore volume were 3.01 nm and 0.96 cm3 · g-1, respectively. These active carbon performance parameters prepared via the present method were compared with experimental data from relevant references. The adsorbance of the active carbon to the methylene blue solution was analyzed. Results showed that the adsorbance of the active carbon increased with the increment in the concentration of the methylene blue solution, stirring time, and the dosage of the active carbon. Therefore, 9.2% is the best adsorption amount of active carbon to the methylene blue solution at 25 mg/L methylene blue solution concentration, 30 mg active carbon mass fraction, and 4 h stirring time.