The Synthesis Of New Adsorbents Based On Starch And Their Adsorption Property For Heavy Metalions

In recent years, with the development of industry, heavy metals are widely used, a new environmental problem-heavy metals pollution has been caused, since metal ions entered human body through the food chain and accumulated in body, brought out serious harm to human health. So the removal of metal ions from aqueous solutions has become a research hotspot, therefore, the materials that have lower prices,lower toxicity nature,stronger adsorption ability for heavy metal ions caused great concern.This paper used starch as carrier material,reacted with small molecules which have the function of adsorption to form the chelating resins, and then further studied the adsorption performance of resins.The main contents of this paper:1.We used starch as the carrier material to synthesize dialdehyde m-phenylenediamine starch (DASMPA).Because the molecule of starch has less effective functions,we used the method of oxidation to modify starch,at same time, in order to determine the effect of oxidation on adsorption performance, three different oxidation degree of starch(DAS1, DAS2, DAS3) were synthetized through changing the amount of periodate. Then we used dialdehyde starch reacted with m-phenylenediamine to generate chelating resins:dialdehyde m-phenylenediamine starch (DASMPA),and they were characterized by FT-IR spectra and element analysis.Dialdehyde m-phenylenediamine starch(DASMPA) can remove Zn (Ⅱ)ion from aqueous solution. Adsorption capacity of DASMPA was studied in detail through the change of adsorption time, pH value, the initial concentration and temperature, we found the adsorption capacity achieved maximum when pH=5, t=1h. The adsorption process meets Freundlich model. The adsorption was exothermic, so lower temperature was preferable to adsorption.2.Dialdehyde5-aminophenanthroline starch(DASAPL) was synthesized by reacting three different oxidation degree of starch(DAS1,DAS2,DAS3)with5-aminophenanthroline,they were characterized by FT-IR spectra,SEM,element analysis and used to adsorb Cd(Ⅱ)ion from solution.The adsorption process was optimized with regard to pH,contact time, initial Cd(Ⅱ) concentration and temperature. The results revealed that pH=5,t=2h were the optimal adsorption conditions.The process of absorption meets the Freundlich model and Langmuir model.The adsorption process was exothermic,so lower temperature is better for adsorption.Then, the reused of DASAPL shown it was an effective adsorbent for the removal of Cd2+from industrial waste solutions.