Study On Dynamic Adsorption Properties Of Modified Peanut Shell

With the rapid development of the printing and dyeing industry,the wastewater of printing and dyeing industry not only contains a large number of carcinogenic and teratogenic heavy metal ions,but also contains a large number of dyes with high chromaticity and difficult to degrade.Therefore,it is of great significance to deal with it.Peanut shell,as a natural renewable resource,has become a research hotspot because of its low cost and natural degradation.In this paper,anionic and amphoteric peanut shells were prepared from massive peanut shells by chemical modification.The dynamic adsorption properties of modified peanut shell for Cu²⁺and reactive blue 19 in printing and dyeing wastewater in self-made fluidized bed and fixed bed were studied and compared.The conditions for preparing anionic peanut shells with massive peanut shells as raw materials were as follows:Na OH dosage 0.54g/g,water-alcohol mass ratio 0.18,chloroacetic acid dosage 0.41g/g,reaction temperature 46.2℃,reaction time 3.77h.The conditions for preparing amphoteric peanut shells with anionic peanut shells as raw materials were as follows:water-alcohol mass ratio 0.18,Na OH dosage 0.61g/g,3-chloro-2-hydroxypropyl trimethyl ammonium chloride（CTA）dosage 2.84ml/g,reaction temperature 65℃,reaction time 11.9h.The dynamic experiment of Cu²⁺adsorption showed that when the adsorption conditions were as follows:peanut shell dosage 11g,flow rate 80m L/min,solution p H 5,initial concentration of solution 25mg/L,and adsorption time 15min,the maximum removal rates of Cu²⁺by primary peanut shell,anionic peanut shell and amphoteric peanut shell in fluidized bed were 39%,88%and 64%respectively,and the maximum removal rates of Cu²⁺in fixed bed were 29%,66%and 47%respectively.The dynamic experiment of adsorption of reactive blue 19 showed that when the adsorption conditions were as follows:peanut shell dosage 13g,flow rate 100m L/min,solution p H 2,initial concentration of solution 100mg/L,and adsorption time 12min,the maximum removal rates of reactive blue 19 by original peanut shell and amphoteric peanut shell in fluidized bed were 49%and 83%respectively,and the maximum removal rates of reactive blue19 in fixed bed were 38%and 53%respectively.FT-IR and SEM were used to characterize the changes of peanut shell before and after modification,and the degree of substitution was measured.FT-IR showed that new functional groups were introduced into the modified peanut shell.Through SEM analysis showed that the apparent morphology of the modified peanut shell changed,and the degree of substitution of anionic peanut shells and amphoteric peanut shells were 0.1437 and 0.1285 respectively.Thomas model was used to fit and analyze the experimental data of adsorption of Cu²⁺and reactive blue 19 by modified peanut shell at different influent concentrations.The experimental results showed that the fitting effect was good.