Synthesis of multi-application activated carbon from oak seeds by KOH activation for methylene blue adsorption and electrochemical supercapacitor electrode

In the current study, an oak as a non-expensive, renewable, and a biomass resource was used to generate a nano-porous activated carbon applicable in methylene blue adsorption from wastewater and energy storage equipment. Furnace activation in the temperature range of 450, 550, 650 and 750 C was used for activated carbon synthesis after infusion with potassium hydroxide. The synthesized activated carbon was characterized using different techniques including nitrogen adsorption/desorption, scanning electron microscopy, and fourier-transform infrared spectroscopy. The results showed that temperature has significant effect on activated carbon efficiency. Specific surface and pore volumes increased with the enhancement of temperature until 650 C, but then it was decreased. Pores volume was consisting of mesoporous and microporous structure. The highest surface area (2896 m2 /g) and pores volume (1.554 cm3 /g) was obtained for the sample prepared at 650 C. Freundlich isotherm model is appropriate for methylene blue adsorption isotherm by the synthesized activated carbon. The maximum adsorption capacity of MB was obtained as 24 mg/g. Moreover, the synthesized activated carbon exhibited the highest specific capacitance when it was used as electrode (551 F/g at current density of 1 A/g) in 1 M sulphuric acid electrolyte and 96% specific capacitance was remained after 5000 charge-discharge cycles at a current density of 10 A/g.