The Carbonization Technology Of Peanut Shell And The Effect Of Micro Structure On The Adsorption Property

The output of peanuts in our country is great, there was large quantity of peanut shellsburned down as fuel every year. It not only wasted resources, but also polluted theenvironment. The study of this paper aimed to looking for a utility product of peanut shellactivated carbon （AC） to purify wastewater not only economically, but also having excellentproperties. The product should have high effective adsorption which could regard as a newtype substitute product of coal AC.In this study, the AC was prepared from the peanut shell by H₃PO₄activation. Thepreparation factors，which effect AC′s on the pore structural characteristics and the adsorptionproperties of heavy metal ions such as impregnation ratio, H₃PO₄concentration, temperatureand time, were discussed. Base on these, the technologic conditions of controlling structureand properties of AC had been established; Investigated the preparation method of peanutshell AC which with no chemistry reagent and inert gas such as N2directly carboned inmuffle furnace. The temperature condition of carbonization and the factor on adsorptioncapacity to heavy metal ions of the peanut shell AC such as peanut shell AC dosage, time, pHvalue, initial concentration of heavy metal ions were discussed; The scan electricmicroscope（SEM） were used to observe the morphology of the peanut shell AC whichprepared in muffle furnace directly with no chemistry reagent, the peanut shell AC were alsoused to recycle Ag in photographic wastewater and removing the micro oil in sea water.Experiment results showed that:The best technologic conditions of preparing AC with peanut shell by the activation ofH₃PO₄using muffle furnace in laboratory are the impregnation ratio is2:1, concentration ofH₃PO₄is50%, activation temperature is500℃and activation time is60min. The adsorptioncapacity to heavy metal ions of the peanut shell AC related to the type of heavy metal ions,the effect of wiping off heavy metal in solution is Cu²⁺＞Pb²⁺＞Ni²⁺; The AC directlycarboned from the peanut shell in muffle furnace could effectively remove the heavy metalions in the solution. The results showed that the effect of wiping off heavy metal in solution isCu²⁺>Ni²⁺. The results also showed that the optimum adsorption conditions of Cu²⁺and Ni²⁺were as follows: the adsorptive time is60min, pH value is5and7respectively. When theconcentration is20mg/L, the peanut shell AC dosage is0.2g and0.4g respectivelyIn the experiment of recovering silver from photographic wastewater by peanut shell AC,time and pH of the photographic wastewater both could affect the adsorption effect of Ag⁺.When the dosage of peanut shell AC is15g·L-1, the adsorption time is30min, pH is about6,a good adsorption effect was got. The desorption time and the desorptive solutionconcentration influenced the desorption effect of Ag⁺. The experimental definite desorption time is40min, the desorptive solution concentration is2%. The experiment of removing theoil in sea water by peanut shell AC, when the peanut shell AC dosage is15.6g/L, theadsorption time is2h, solution pH is under4, the peanut shell AC could effectively removethe oil in sea water. The peanut shell AC could effectively recycle the silver in photographicwastewater and the oil in sea water; Compared with coal AC, the peanut shell AC had bettereffect on removing the micro oil in sea water. To a certain, it could substitute for coal AC.