The Powder Activated Carbon,zeolite Powder And Polishing Resin Pair In Emergency Experimental Study On Adsorption Of Cadmium And Lead

Heavy metals are a common type of pollutant in sudden pollution incidents.In recent years,the frequency of sudden heavy metal pollution incidents in China has also continued to increase.This article is based on a scientific research project carried out by the South China Institute of Environmental Sciences of the Ministry of Ecology and Environment to ensure the safety of drinking water sources.Three types of emergency materials,activated carbon,zeolite powder,and polishing resin,which are common in emergency,are used for two heavy metals Cd²⁺And adsorption of Pb²⁺.The main research conclusions are as follows:?1?When the pH value is 8,the initial concentration of cadmium ion is 2.0 mg/L,and the adsorption temperature is 25°,the adsorption capacity of powdered activated carbon,zeolite powder and polishing resin to cadmium ion is 0.937 mg/g and 1.147 mg/g,1.632mg/g,The adsorption effects of the three on cadmium are:polishing resin>zeolite powder>powder activated carbon;under the condition of pH value 8,lead ion initial concentration of 5.0mg/L,and adsorption temperature of25°,The adsorption capacity of powdered activated carbon,zeolite powder and polishing resin to lead ions were 2.376mg/g,2.959mg/g,2.806mg/g,respectively.The adsorption effects of the three on lead are:zeolite powder>polishing resin>powder activated carbon.?2?The adsorption kinetics of powdered activated carbon,zeolite powder and polishing resin on cadmium metal shows that the adsorption process of the three is more in line with the quasi-second kinetic model,indicating that the reaction mechanism of the three emergency materials to cadmium metal is mainly affected by Adsorption control.According to the Langmuir adsorption isotherm model,the process of adsorbing cadmium is monolayer adsorption;the adsorption kinetics of powdered activated carbon,zeolite powder and polishing resin on metal lead shows that the adsorption process of the three is more in line with the quasi-second level The kinetic model shows that the reaction mechanism of the three emergency materials to metal lead is also mainly controlled by chemical adsorption,and in the isothermal adsorption model,the powder activated carbon and polishing resin have the highest degree of fit to the Freundlich adsorption model,while the isothermal adsorption of zeolite powder The line is more in line with the Temkin adsorption model;the thermodynamic parameters of the three emergency adsorption materials indicate that the process of cadmium and lead adsorption is an endothermic reaction.?3?Scanning electron microscopy?SEM?,energy spectroscopy?EDS?and infrared spectroscopy?FTIR?were used to characterize powdered activated carbon,zeolite powder and polishing resin before and after adsorption of metal cadmium and lead.By comparing the scanning electron microscope before and after adsorption,we can clearly see that the surface and internal structure have changed.Energy spectrum analysis proves that the three emergency adsorption materials can effectively adsorb cadmium and lead in the solution.Through FTIR analysis,it can be seen that the adsorption process of powdered activated carbon is mainly due to the function of aldehyde carbonyl and hydroxyl groups,the adsorption process of zeolite powder is mainly due to the function of hydroxyl groups and silicates,and the adsorption process of polishing resin is mainly due to the effects of hydroxyl groups or acyl groups.?4?In the competitive adsorption experiment of heavy metal cadmium and lead with powdered activated carbon,zeolite powder and polishing resin,through comparison,it was found that adding lead ions to a single cadmium solution has a great effect on the adsorption of cadmium on powdered activated carbon,zeolite powder and polishing resin.To add cadmium ions to a single lead solution.