Activated carbon prepared from soybean straw for phenol adsorption

Soybean [Glycine max (L.) Merr.] straw (SS) was employed as a precursor for the preparation of activated carbon by zinc chloride (ZnCl2) activation. Thermogravimetric analysis (TGA) of ZnCl2, SS and ZnCl2/SS mixtures were carried out. And the morphology of the activated carbon derived from soybean straw (SSAC) was tested by scanning electron microscopy (SEM). The nitrogen adsorption–desorption experiments were performed at 77 K to determine the pore structure of SSAC. αs-plot and DR-plot were used to calculate the micropore volume of SSAC to investigate the effect of the additive amount of ZnCl2 on the pore structure. It was shown that the maximum surface area of SSAC calculated by BET was as high as 2271 m2/g. The pore distribution analyzed by BJH was between 1.73 and 3.95 nm. The Langmuir and Freundlich equilibrium isotherm theories were applied to describe phenol adsorption respectively. Maximum monolayer adsorption capacity of phenol was 278 mg/g. The value of RL was found to be below 1.0, indicating that the resultant activated carbon was favorable for phenol adsorption.

► Activated carbons are prepared from soybean straw by zinc chloride activation.
► The resultant activated carbons possess large surface areas and high pore volumes.
► The resultant activated carbons are favorable for organic pollutants adsorption.