Ultrasound-assisted preparation of activated carbon from alkaline impregnated hazelnut shell:An optimization study on removal of Cu~(2+)from aqueous solution

摘要

In recent years,the use of new technologies based on non-conventional energies such as ultrasound gains increasing importance.Ultrasound exhibits several beneficial mechanical effects in solid-liquid systems by means of the cavitations phenomenon.In this study,activated carbon adsorbent for removing heavy metals cations such as Cu~(2+)from aqueous solutions has been prepared.For this purpose,hazelnut shells were impregnated with KOH solution under ultrasound irradiation.After filtration,hazelnut shells have been carbonized under inert N_2 atmosphere.The experiments were planned by fractional factorial design and central composite design.Activated carbons were characterized by their copper adsorption capacity.Optimum process conditions were obtained by using a constrained optimization program as follows:particle size 0.83 mm,ultrasound power/volume 19W/L,impregnation ratio 0.06 g/mL,impregnation time 143 min,activation temperature 838 deg C and activation time 19min,following with maximum adsorption capacity was found as 40mg Cu~(2+)/g Ac.Activated carbon with the maximum adsorption capacity was further characterized by using scanning electron microscopy and its open pore structure was observed.