Removal Of Chromium And Uranium Ions From Water By Modified Activated Carbon

With the increasing degree of social modernization,the application of heavy metals is more extensive,at the same time,accompanied by a large number of heavy metal wastewater.Heavy metals are released into the natural environment for various reasons.It is widely found in water and soil.When heavy metals enter the human body,they accumulate in the human body and are difficult to be discharged from the body,thus causing a variety of diseases to humans.Heavy metal pollution is characterized by enrichment,non-biodegradability and variable morphology.Therefore,it is very important to choose a more appropriate removal method.Adsorption method as a commonly used method to deal with heavy metals has the characteristics of simple and easy operation,high efficiency and low cost.Therefore,the experimental method used in this paper is adsorption method.In this paper,the removal of Cr(Ⅵ)and U(Ⅵ)from simulated heavy metal wastewater by activated carbon and modified activated carbon was systematically studied,and the adsorption mechanism of activated carbon was deeply explored.Furthermore,the activated carbon was modified by ammonia and potassium permanganate to investigate the adsorption behavior of Cr(Ⅵ)and U(Ⅵ)respectively.In order to further understand the mechanism of adsorption of heavy metals by activated carbon and modified activated carbon,this paper used SEM,Zeta potential,infrared and other instruments to characterize activated carbon and modified activated carbon.1.The results about the adsorption of Cr(Ⅵ)by AC.The experimental results show that both 200 mesh activated carbon and 20-50 mesh activated carbon(AC)have the best adsorption effect on Cr(Ⅵ)under strong acidic conditions.Under the same experimental conditions,the adsorption effect of 200 mesh activated carbon was better than that of 20-50 mesh activated carbon(AC).The adsorption kinetics results show that the adsorption of Cr(Ⅵ)by the two kinds of activated carbon conform to the pseudo-second-order kinetics model.Thermodynamic results show that the adsorption of Cr(Ⅵ)by the two kinds of activated carbon conforms to Langmuir isothermal adsorption model.The results show that ammonia modified activated carbon(GAC)also has the best adsorption effect on Cr(Ⅵ)under the condition of strong acid.The adsorption of Cr(Ⅵ)by ammonia modified activated carbon(GAC)can last for 4 hours,and the adsorption rate is slightly higher than that before modification.In a certain temperature range,the higher the temperature is,the better the adsorption effect is.Kinetic study shows that the adsorption of Cr(Ⅵ)by ammonia modified activated carbon(GAC)conforms to the pseudo-second-order kinetic model.Thermodynamic study shows that ammonia water modified activated carbon(GAC)fits Langmuir isothermal adsorption model.2.The results about the adsorption of U(Ⅵ)by AC.20-50 mesh activated carbon(AC)has the best adsorption effect on U(Ⅵ)when the p H value is 6.The adsorption time of 20-50 mesh activated carbon(AC)on U(Ⅵ)lasted for 6 hours.Kinetic study shows that the adsorption of U(Ⅵ)by 20-50 mesh activated carbon(AC)conforms to the pseudo-first-order kinetic model.Thermodynamic studies show that Freundlich isothermal adsorption model is consistent with 20-50 mesh activated carbon(AC)adsorption of U(Ⅵ).Also,potassium permanganate modified activated carbon(MAC)has the best adsorption effect on U(Ⅵ)when p H value is 6.Kinetic study shows that the adsorption model conforms to the pseudo-first order kinetic model.Thermodynamics is consistent with Freundlich isothermal adsorption model.For the adsorption of U(Ⅵ),potassium permanganate modified activated carbon(MAC)is better than 20-50 mesh activated carbon(AC).