Ligand-Enhanced Separation of Divalent Heavy Metals from Aqueous Solutions Using a Strong-Acid Ion-Exchange Resin

Abstract

Experimental studies on the cation-exchange separation of three pairs of divalent metal ions (Zn/Cu, Co/Cu, and Ni/Cu) from water in the presence of water-soluble ligands were made at 298 K. Four ligands including ethylenediaminetetraacetic acid, nitrilotriacetic acid, iminodiacetic acid, and citrate were selected. Experiments were performed as a function of the solution pH (1.0−6.0) and the concentration ratio of the ligand to total metals (0−1). It was shown that the exchange selectivity was enhanced when the anionic ligands were present. The extent of enhancement strongly depended on the solution pH but was not completely related to the metal-complexing affinity of the ligands. A parameter, based on the combinations of the overall formation constants of the ligands with two metals, was thus proposed to correlate the exchange selectivity obtained under various sets of metal pairs and anionic ligands. This correlation allowed selection of a suitable type or amount of the anionic ligands for effective separation of a given pair of heavy metals.

Adsorption performances and mechanisms of the newly synthesized N,N′-di (carboxymethyl) dithiocarbamate chelating resin toward divalent heavy metal ions from aqueous media

“…Hereby, the chelating interaction is in the order of Pb(II) > Cu(II) > Ni(II), the same trend with the kinetic performance in the above section. In addition, the calculated adsorption capacity of PSDC toward Pb(II) is far greater than that of DTC-resin reported earlier, which should be attributed to the introduction of IDA moiety and increase in sulphur fraction in the chelator supported material [15][16][17][18]. And the predicted Q 0 for three metals is greater than those observed, with the reason of the difficulties for metal ions to access all of the potential binding sites on the matrix.…”

“…Additionally, the adsorption mechanisms and separation behaviors were not systematically investigated and exploited. Recently, polymers containing the iminodiacetic acid (IDA) as the functional group have been synthesized and widely used for a range of treatment processes to eliminate heavy metal ions from different metal-loading wastewaters [18]. Such polymers with EDTA-like group structure, offer extremely high affinity and selectivity toward commonly encountered metal cations [19].…”

Preparation and characterization of N-methylene phosphonic and quaternized chitosan composite membranes for electrolyte separations

“…Separation of Ca 2+ and Mg 2+ from Na + is also a serious problem for the removal of hardness from ground water, boiler feed water, production of pure salt, etc. Many technologies such as ion-exchange resin [1], chelation of bivalent ions [2,3], ultrafiltration or nanofiltration [4,5], and electrodialysis [6,7] have been used by different scientists to solve this problem. But the use of hazardous chemicals and solvents during the preparation of membranes or resins is a serious problem.…”

Application of Time-Lapse Ion Exchange Resin Sachets (TIERS) for Detecting Illegal Effluent Discharge in Mixed Industrial and Agricultural Areas, Taiwan

“…Many studies have been done to determine the soil pollutant concentrations by using XRF techniques [35,[38][39][40]. Moreover, the ion exchange method has been widely used for water purification and wastewater treatment, especially in the recycling process of Chromium(III), Copper(II) sulfate, and Nickel(II) sulfate from the electroplating effluents [41][42][43]. As the ion exchanger has ionogenic groups to which counter ions can be bound, the ions of same electric charge are exchanged when the liquid is contacted with the ion exchanger as the ion exchange reaction.…”