The Research On The Modification Of Peanut Shell Cellulose And The Mechanism Of Cd(?) Adsorption

In recent years,more and more pollutants discharged into the environment and heavy metal pollution is more serious.Once the water environment polluted by heavy metals,it will not only endanger human health,but also destroy the ecological balance.Therefore,efficient management of heavy metal pollution has draw people's attention.The adsorption method has become a widely used method.Agricultural and forest wastes have also become good raw adsorbent materials.Rice husk,corn cob and peanut shell are common agricultural and forest wastes.After modification,the Cd2+ solution was adsorbed by the cellulose in rice husk,corn cob and peanut shell.By comparing the adsorption effect,it can be concluded that the grafting modification of peanut shell was the most obvious materials during these three materials.In this study,after the treating of peanut shell and selecting the appropriate initiator and monomer,the peanut shell can be grafted and copolymerized in the acidic conditions.The orthogonal experiment results showed that the grafting efficiency of peanut got the highest as 21.21%at the condition of 6 mmol the initiator,4 mL monomer,and the solid-liquid ratio of peanut shell and H2SiO3 taken as 1g:100mL.In the control experiment,it was found that the peanut shell had higher grafting rate in the H2SiO3 than in HNO3 environment.After the preparation of the adsorbent,the adsorption experiment was carried out on the Cd2+.The results showed that when the pH was 6,temperature was 35 ?,the initial concentration was 100 mg/L,and the time of adsorption for 24 h,the effect of adsorption was the best.In the solution with Cu2+,Pb2+ and Cd2+ coexistence,the removal rate of modified peanut shell gradually decreased with the increase of initial concentration of Cu2+,Pb2+.The competitive adsorption capacity of modified peanut shells was Cu2+>Pb2+>Cd2+.Through the analysis of adsorption isotherm and adsorption dynamics and model fitting,we can conclude that the adsorption isotherm could be correlated with Langmuir isotherm equation.When the adsorption temperature was 35 ?,the maximum adsorption capacity of modified peanut shell cellulose was 31.6055 mg/g.The kinetic studies showed that the pseudo second-order rate equation could fit the experimental data well.The the maximum adsorption capacity was 21.6029 mg/g.From the adsorbent regeneration results,the removal effect of Cd2+ on the peanut shell was:HCl>NaCl>pure water.