The Study On Characteristics Of The Adsorption Of Lead And Cadmium To Activated Sludge

With the rapidly development of our country and the construction of sewage treatment plants, the problem of water pollution had been solved to a large extent with the treatment emissions on the sewage.But the followingproblem is the a large number of the residual activated sludge produced by the sewage treatment plants. It is often requires a lot of money to disposal the residual activated sludg.It may causesa secondary pollution ifthe sludge piled up optionaliy..It will be saving resource and improving the economic benefit that using waste treat waste ofthe residual activated sludge to adsorp the heavy metals.This paper studied the adsorption between the residual activated sludge and the typical heavy metal ions lead and cadmium, and discussd the factors of the adsorption of sludge to lead and cadmium.Compared the difference on the ability of the adsorption of the sludge to lead and cadmium.And studied the characteristics of the thermodynamics and kinetics of theadsorption of lead and cadmium, and calculated the sludge thermodynamic parameters and kinetic parameters. Besides, studiedthe removing of the heavy metals in sludge.The study found that the adsorption of the activated sludge of lead and cadmium is higher, and a greater affinity to lead than cadmium. The adsorption depended onthe time,sludge quantity, and the pH value to a large degree, and the influence of temperature is small.In the coexistence of lead and cadmium adsorption system, the adsorption of cadmium and lead is mutual inhibiyion, and the inhibitory effect of lead is stronger than cadmium.. The adsorption of ctivated sludge to lead and cadmium conforms to the Langmuir model.The process of the adsorption of lead and cadmium is endothermic, and the adsorption is spontaneous, andthe spontaneous tendency to lead is stronger than cadmium. The kinetics adsorption of lead and cadmium conforms to described by the quasi secondary dynamics equation.The removal of lead and cadmium is different by the hydrochloricacid, citric acid andEDTA,and thecitric acid is best.So I think that can use the citric acid to removethe heavy metasl,and to improve the resource utilization of activated sludge.