Study On Preparation Of New Chelating PAM-gel And Its Performance Of Adsorpting Heavy Metal Ion

In recent years, frequent incidents of water pollution and characters of heavy metaldiffusion resistance, difficult to control have become one of the largest water pollution healthhazard to human life and also pose a serious pollution to the surrounding soil, groundwaterand air. In pollution water, mercury, lead ions are major pollutants with the feature of widesource, long time residues, easy to accumulate, biodegradable. However, the method to theremoval of these water contaminated with heavy metal ions is unsatisfactory, such asdrawbacks of reagent delivery capacity, high material cost, easy to cause secondary pollution,difficult to reach deeply processing, so it is urgent to develop materials and methods ofefficient, low-cost, high selectivity, low energy consumption, being able to solid-liquidseparation of heavy metal ions.mercaptoethylamine (AET) and dithizone (DTZ)) can be chelated with Cd2+，Hg2+andPb2+. Because of the advantages of the flocculant can solid-liquid separation in watert，the twotypes of flocculant have the effect of removing heavy metal ions. Meanwhile, the chelatinggel has the features of simple synthesis process, high selectivity, easy-to-liquid separation,low concentration wastewater containing heavy metal ions, etc, which is expected to becomea new, low-cost wastewater treatment materials.It can be deduced that optimal synthesis parameters of2-cysteamine chelating anddithizone chelate gel is gained with grafting ratio of respectively99%and89%. It is analysedby infrared spectroscopy confirming that polyacrylamide gel is grafted by chelating group.Optimal performance parameters of removing heavy metal ions (Cd2+、Hg2+、Pb2+) bythese two chelating gel in adsorption experiments. Under optimal conditions, the removingefficiency of Hg2+, Pb2+by the2-mercaptoethylamine chelating gel is respectively99.6%and72.3%and dithizone chelate gel removing efficiency of Cd2+, Hg2+, Pb2+is respectively99.9%,99.5%,99.3%. Experiments show that the effect of these two new gel removing heavy metalis excellent, especially gel adsorption of dithizone chelating is best and it can be reacheddischarge standards after a single treatment of adsorption of cadmium, mercury, lead ions.According to adsorption thermodynamic and the adsorption kinetics mechanism analysisof the process of chelating gel adsorbing three heavy metal ions, the adsorption capacityadsorption, rate equation and Isothermal temperature adsorption model in the adsorptionprocess is obtained. The apparent activation energy Ea and thermodynamic characteristicsconstant (△G,△H,△S) is calculated and it is determined that the adsorption course is in line with the Langmuir isotherm adsorption belonging to two kinetic models. These data illustratesthe experimental results matching with the reaction and provides a theoretical basis for thelatter study.Finally, the parameters and conditions of using chelating gel to remove heavy metal ionsin industrial wastewater according to obtained experimental parameters is Preliminarycalculated. And equipment selection of process is discussed, finally it is confirmed thatfeasibility of this process in heavy metal ions treatment.