Study On The Treatment Of Cadmium Pollution Based On The Adsorption Technology Of Chitosan Composite Modified

Soil safety is related to people's livelihood safety.The problem of low concentration cadmium pollution in soil and water has become increasingly prominent.It is a good breakthrough to prepare environmentally friendly solidifying/stabilizing agents with low cost and strong stability..Both chitosan and activated carbon are very good adsorption materials.Based on the study of modified chitosan to make composite adsorbent activated carbon/chitosan,The adsorbents were characterized by a series of characterization methods,analysied of the microstructure and surface functional groups,This subject has been researched the adsorption effects of different adsorbents on cadmium and their influencing factors in the adsorption process,Furthermore,the adsorption mechanism of adsorbent was discussed by using kinetic model and isothermal adsorption model,It can provide reference and theoretical support for the future restoration of cadmium contaminated soil,So it has important practical significance.The result show that:?1?Using activated carbon as carrier material to make powder and granule of adsorbent in two different forms,The static adsorption experiments showed that adsorption capacity of powdered and granular adsorbents is 14.05 mg/L and 6.2 mg/L for cadmium adsorption,when pH>7,the removal rate of Cd²⁺by both adsorbent materials is above 90%;Compared with granular adsorbent,the adsorption of unit adsorbent is larger for powder adsorbent,It indicates that the powdered activated carbon/chitosan adsorbent has a larger specific surface area and more surface adsorption sites.?2?The adsorption behavior of Cd²⁺by the two adsorbent materials is more consistent with the quasi-second-order kinetic equation and the Langmuir isothermal model.Chemical adsorption is the main adsorption rate control step.The adsorption mechanism of sorbent on cadmium is mainly the complexation of surface functional groups.It is closed for saturated adsorption between measured by the experiment and The equilibrium adsorption amount measured by the experiment is close to the calculated by the Langmuir adsorption isotherm model,So it is accord with monolayer adsorption theory,The R_L of the adsorption for Cd²⁺is 0¹ by the two adsorbents,which is favorable adsorption.?3?Study on the Langmuir adsorption isotherm model under different temperature,The results show that heating is beneficial to enhance the adsorption effect of powdered adsorbent on Cd²⁺.Heating is beneficial to enhance the adsorption effect of powdered adsorbent on Cd²⁺.When the temperature is 298.15K and 303.15K,Heating is beneficial to adsorption of Cd²⁺by granular adsorbent.At 308.15 K,the adsorption is lowered for amount of the particulate adsorbent.Comprehensive research presents that the powdered activated carbon/chitosan adsorbent has better adsorption effect,and has certain application prospects for the repair of cadmium contaminated soil.