Study On Adsorption Properties And Mechanism Of Stabilized Ferrous Sulfide Nanoparticles For Arsenic In Water

At present,over more than a hundred of millions of people are exposed to high Arsenic environment round 70 countries and regions in the world.Arsenic can enter the human body through breathing,skin contact,food chain transmission,etc.,causing lesions or canceration of multiple tissues or organs of the human body.The Arsenic has been listed as one of the carcinogens by pathologists with the poisoning dose of 0.01-0.052g and the death volume of0.06-0.2g.In this thesis,Nano-ferrous sulfide,a kind of stabilize particles made by using CMC,starch and chitosan which is used to treat the Arsenic wastewater,was studied about its adsorption properties and mechanism of Arsenic,in order to provide theoretical basis and technical support for the application of nanometer sulfide ferrous in Arsenic pollution control and environmental remediation.In this thesis,through Homogeneous precipitation method to prepare nano-ferrous sulfide by using ferrous sulfate and sodium sulfide as raw materials under the protection of nitrogen atmosphere and prepare stable nano-sulfide ferrous particles by using CMC,starch and chitosan,study the amounts of iron sulfide,the reaction time and the pH value on the adsorption performance of As(V)in wastewater.Tem,XRD,FTIR,XPS and other methods were used to characterize the materials in order to study its structures and properties.The results show that,firstly,the stable nano-sulfide ferrous particles prepared are unshaped amorphous,and the structure of CMC,starch and chitosan contain a large number of carboxyl groups,hydroxyl groups and amino group,which can increase their stability of chelatig with the sulfide ferrous.Secondly,the optimum quality ratio of CMC,starch,chitosan and ferrous sulfide are:1:1,5:1 and 1:1,respectively,and the optimum dosage in the treatment of Arsenic wastewater with 50ml concentration 10ppm was 5mg,10mg,7mg.CMC-FeS,Starch-FeS,Chitosan-FeS showed strong adsorption ability to As(v),the maximum adsorption amount was:101.317mg·g~-,50.813mg·g~-,72.833mg·g~-,and the adsorption process of three stable nano-sulfide ferrous materials to As(v)was divided into two stages,0-20min adsorption speed is faster,can reach more than 80%,20min after adsorption speed is slow,can be completed in 180min adsorption,the experimental results of the fitting found,CMC-FeS,Starch-FeS,Chitosan-FeS the adsorption process of arsenic is consistent with quasi-two kinetic equation and Freundlich isothermal equation,and CMC,starch and chitosan stable nano-sulfide ferrous particles have better removal of As(V)in acidic conditions,and the optimum pH conditions are:5,3,5,and has a medium and effect on the pH of the solution.