Investigation on pore structure regulation of activated carbon derived from sargassum and its application in supercapacitor

Abstract

In order to realize the effective regulation of the pore structure of activated carbon and optimize its pore structure properties as electrode material, the effects of activation temperature, activation time and impregnation ratio on the specific surface area, total pore volume and average pore diameter of activated carbon are studied by orthogonal experiment with sargassum as raw material. In addition, the electrochemical properties of sargassum-based activated carbon (SAC) and the relationship between the gravimetric capacitance and specific surface area of SAC are also studied. The SACs prepared under all conditions have high specific surface area (≥2227 m2 g-1) and developed pore structure, in which the micropore diameter is mainly concentrated in 0.4~0.8 nm, the mesopore diameter is mainly concentrated in 2~4 nm, and the micropore content is much higher than that of the mesopore. In the activation process, the impregnation ratio has the greatest effect on the specific surface area of SAC, the activation temperature and impregnation ratio have significant effect on the total pore volume of SAC, and the regulation of the average pore diameter of SAC is mainly realized by adjusting the activation temperature. The SACs exhibit typical electric double layer capacitance performances on supercapacitors, delivering superior gravimetric capacitance of 237.3 F g-1 in 6 mol L-1 KOH electrolyte system at current density of 0.5 A g-1 and excellent cycling stability of capacitance retention of 92% after 10000 cycles. A good linear relationship between gravimetric capacitance and specific surface area of SAC is observed.

Optimization of Cr (VI) removal from aqueous solution with activated carbon derived from Eichhornia crassipes under response surface methodology

“…After chemical and thermal activation of the material, the surface area increased to 794.2 g/m 2 . The increment in the number of pores might be due to the activation of the material by acid and heat [ 69 , 70 ]. After the activated carbon adsorbs Cr (VI) ion, the surface area decreased to 412.6 g/m 2 .…”