Orthogonal Experiment on Adsorption Conditions for Cr(VI)in Wastewater by Modified Peanut Shell

[Objective]The study aimed to study the adsorption capacity on Cr(Ⅵ)in wastewater by modified peanut shell.[Method] The peanut shell was made for the modification treatment with the phosphoric acid solution and the Cr(Ⅵ)solution was prepared at different condn.The effects of Cr(Ⅵ)initial concn,adding dosage of modified peanut shell,pH value and reaction time on the adsorption rate were studied through the single factor test and the adsorption conditions for Cr(Ⅵ)in wastewater by the modified peanut shell were optimized through the orthogonal test.[Result]The range analysis showed that,among the factors that affected the adsorption effect,the effect of pH value was maximum,followed by the adding dose and the reaction time and the effect of Cr(Ⅵ)initial concn.was minimum.The optimal conditions of adsorption were as follows:the value of pH was 6,the initial concn.of Cr(Ⅵ)was 40 mg/L,the dosage of modified peanut shells was 30 g/L and the reaction time was 100 min,under which,the adsorption rate on the Cr(Ⅵ)could be as high as 96.81%.The adsorption capacity on Cr(Ⅵ)in wastewater of modified peanut shell was obviously better than that of the non-modified peanut shell.[Conclusion]The study provided a valuable reference for the comprehensive utilization of peanut shells and the treatment research on Cr(Ⅵ)in the wastewater.