Adsorption Characteristics Of Pb²⁺ And Cd²⁺ And Characterization Of Particles Surface In Loutu Soil And Hetu Soil

With the continuous development of society,soil heavy metal pollution has been widely concerned.In order to solve this problem,the government has issued The Soil Pollution Prevention and Control Action Plan.Due to the wide range and high degree pollution of Cd²⁺and Pb²⁺,they have become the focus of heavy metal pollution prevention and control.In this paper,the kinetics and thermodynamics of adsorption of Pb²⁺and Cd²⁺on Lou soil and Cinnamon soil were studied.The research results can provide a certain basis for understanding the adsorption mechanism of heavy metals on soil,and provide basic data for the prevention and control of Pb²⁺and Cd²⁺pollution.The main conclusions are as follows:（1）The adsorption process of Pb²⁺and Cd²⁺can be divided into two stages:fast adsorption and slow equilibrium.After more than 90%rapid adsorption,the adsorption rate gradually decreases and tends to be stable,and finally reaches the dynamic equilibrium of adsorption-desorption;The adsorption rate of Pb²⁺was higher than that of Cd²⁺.（2）The adsorption capacity of Pb²⁺and Cd²⁺increased with the growth of the initial concentration of Pb²⁺and Cd²⁺in solution,the maximum adsorption capacity and adsorptivity of Pb²⁺were greater than that of Cd²⁺.The adsorption rate and adsorption capacity of Pb²⁺and Cd²⁺increased with the growth of temperature.（3）The increase of temperature was beneficial to the adsorption of Pb²⁺and Cd²⁺in the soil used in the experiment.After the removal of organic matter,the adsorption capacity of Pb²⁺and Cd²⁺decreased.（4）After the adsorption of Pb²⁺and Cd²⁺,the SEM results showed that the adsorbed soil particles changed from loose to aggregates,the small pores changed from more to less,and more small particles were attached to the surface.EDS results showed that Pb²⁺could quickly find the binding point and enter into the interior of soil particles,while Cd²⁺was evenly distributed on the surface of soil particles.（5）After the adsorption of Pb²⁺and Cd²⁺by soil,XRD results showed that the crystal structure of soil was not been destroyed.But the dispersion of Si O₂became higher and most of them were amorphous,which was more conducive to the contact and adhesion of Pb²⁺and Cd²⁺with soil particles.FTIR results showed that the more kinds and quantity of functional groups in soil,the more favorable to the adsorption of Pb²⁺and Cd²⁺.