The Study Of Activated Carbon Prepared Using Agricultreal Waste

Activatied carbon is a porous material with large surface area,so it can be used as excellent adsorption and catalyst carrier.The chemical properties of activatied carbon is very stable.It is extensively used in industries such as pharmaceuticals processing,food processing,electronic industry,environmental protection,chemical industry and national defense etc.With the used field of activated carbon extend,there is a good market for activated carbon.The usual raw materials such as coal,petroleum,asphaltum and wood dust are nonrenewable or renewable for a long time,thus,it is necessary to exploit new resource to produce activated carbon.Agriculture waste causes scholars' interest.Agricultural waste is by-product generated in the agricultural processing and forestry production processing,mainly including tree bark,rice hull,sawdust,straw,bagasse,and animal dung etc.The accumulation of a large number of agricultural waste has caused serious environmental problems and resource waste problem.In this paper,activated carbon was prepared using the chestnut shell and rice hull by different activations in different conditions.The effect of operation parameters such as pregnation ratio,activation temperature and activation time on the adsorption of activated carbon was measured and analyzed.In order to optimize these conditions the adsorption propeties for iodine and methylene blue of activated carbon ware studied.The experimental results show as follows.(1)The chestnut shell as raw material,first of all,brown pigment was extracted with aqueous and ethanol solution separately,and then activated carbon was prepared by zinc chloride activation and phosphoric acid activation separately.Conclutions can be made.?The main absorption wavelength of brown pigment extracted with 50%of ethanol solution from chestnut shell is 200-400nm;brown pigment has maximum absorption peak in the wavelength of 240nm,300nm and 370nm.?the optimize conditions of phosphoric acid activation to produce activated carbon are phosphoric acid concentration 40%,activation temperature 400 ? and activation time 45min,and the adsorption for methylene blue and iodine of activated carbon is 165 mg/g and 779.3 mg/g separately;?the optimize conditions of zinc chloride activation are zinc chloride concentration 60%,pregnation ratio(the mass ratio of chestnut shell and ZnCl2 solution)1:2.5(g/g),carbonization temperature 250 ?,carbonization time 30min activation temperature 600?and activation time 60min,and the adsorption for methylene blue and iodine of activated carbon is 225 mg/g and 922.90 mg/g separately.(2)Activated carbon was prepared using the rice hull by activations of NaOH and KOH in different conditions such as boiling temperature,high activation temperature,and high activation pressure.The several conclusions can be made from the experimentions:?the adsorption of methylene blue of activated carbon using NaOH activation at boiling tempereture is 50mg/g.In the same conditions,the activated carbon was produced using the prepared activated carbon,the methylene blue value 80.5mg/g.The adsorptionof third times of activation has nothing with the second activation.?the optimize conditions of activation carbon using NaOH activation with high pressure are the mass ratio of alkali and carbon 1:5,reaction time 3h,reaction temperature 140?,and the the methylene blue value is 161.6mg/g,the iodine value 245.6mg/g.?The optimize conditions of activation carbon prepared by KOH activation is that the ratio of alkali and carbon 3:1,activation temperature 750?,activation time lh,and the value of methylene blue is 245.Omg/g,the iodine value 1028mg/g.