Application of novel complexing agent in sorption of heavy metal ions from wastewaters on ion exchangers of various types

Abstract

Ethylenediaminetetraacetic acid (EDTA) and nitrilotriacetic acid (NTA) are very effective chelating agents used in many branches of industry. However, they are characterized by low biodegradability (EDTA) and carcinogenic effect (NTA), additionally they are quite persistent in the environment. The search for a cost effective alternative to these two most frequently used chelating agents has long been an industry target. One of them is N,N-bis(carboxylmethyl)-L-glutamic acid whose tetrasodium salt known as Dissolvine GL-38. The aim of our work was to investigate Dissolvine GL-38 as a potential alternative for EDTA or NTA in effective removal of heavy metal ions from waters and wastewaters. In the presented paper there were used for the sorption of of heavy metal ions two commercially available ion exchangers: Lewatit MonoPlus MP 64 and Purolite S-920. A series of experiments was conducted to optimise the method for the Cu(II), Zn(II), Ni(II) and Cd(II) removal from industrial effluents. It was found that the sorption efficiency of the monodisperse polystyrene anion exchanger as well as the chelating ion exchanger varied depending on metal ions concentration, pH, phase contact time, agitation, temperature and properties of ion exchangers.