The Research On The Agricultural Organic Waste To Adsorb Cr（Ⅵ）、Cu²⁺ From Wastewater

On one hand the pollution of heavy metals from industrial wastewater isincreasingly serious, on the other hand a lot of agricultural organic waste aren’t takenfull advantage of. This study investigated the effects of different biomass on theadsorption of hexavalent chromium ion and copper ion. The results showed that theadsorption effect of peanut shell was the best, the second was corn cob, then wheatshell while the corn stalk had the lowest adsorption effect. The adsorptionperformance of the modified peanuts shell and corn cob were made furtherinvestigation deeply.The experments results indicated that the corn cob which modified by tartaricacid has the best effect on adsorbing the hexavalent chromium from water.Theoptimum condition of adsorbing the hexavalent chromium onto the modified corn cobwas that the temperature was55degree Celsius,the initial concentration of thehexavalent chromium solution was50mg/L,the pH was2and the adsorption time was90minutes.Under this situation,the ratio of elimination of the modified corn cobadsorbing the hexavalent chromium was93%while the common one was74.5%.Theadsorptions isotherms belonged to S type,adsorption equation was fitted to theFreundiich equation and adsorption kinetic date of the hexavalent chromium wasfitted to the second rate equation.Peanut shell modified by ethylic acid had the best effect on adsorbing thehexavalent chromium from water.The optimum condition of adsorbing the hexavalentchromium onto the modified peanuts shell was that the temperature was30degreeCelsius,50mg/L hexavalent chromium solution treated by0.2g modified peanutsshell,the reasonable pH was3and the adsorption time was90minutes.Under thissituation,the ratio of elimination of the hexavalent chromium onto the modifiedpeanut shell was99.1%while that of the unmodified was83.5%.The adsorptionisotherms belonged to L type,adsorption law conformed to the Freundiich andLangmuir equation.The adsorption processes accorded with second rate equation.The corn core which modified by sulphuric acid and37%formaldehyde solution has the best effect on adsorbing the copper ion.The optimum condition of adsorptionwas that the initial concentration of copper ion is1mg/L,the quantity addition of themodified corn cob was0.2g,the temperature was30degree Celsius,pH was6andconcussion time was120minutes.Under this situation,the ratio of adsorption wasabout99%.The adsorption isotherms belonged to L type,adsorption law conformed tothe Freundiich equation and belonged to monomolecular layer adsorption and abidedby imitation second dynamic model.The peanuts shell which modified by sodium hydroxide and ortho-phosphoricacid has the best effect on adsorbing the copper ion.The optimum condition ofadsorption is that the temperature is40degree Celsius,the initial concentration ofcopper ion is1mg/L,pH was6and the adsorption time was150minutes.Under thiscondition,the ratio of elimination was98.5%while the unmodified was81.3%.Theadsorption isotherms belonged to C type,adsorption law conformed to the Freundiichequation and belonged to monomolecular layer adsorption and abided by innerpervasion dynamic model.According to the results of the experiment，the absorption characteristic of thecorn cob and peanuts shell were different.The adsorption effect of the peanuts shellwas better than that of corn corb in every aspect.Agricultural organic wastes are cheapand easy to get and have ideal effects on adsorbing the metal in polluted waterthrough modification treatment which can turn harm into benefit and has a promisingfuture.