Effect of Microwave Radiation on the Synthesis of Ion Exchange Resins: A Comparative Study

Abstract

A series of new ion exchange resins was synthesized in a microwave radiation field by modification of chloromethylated styrene/divinylbenzene (S/DVB) and vinylbenzylchloride/divinylbenzene (VBC/DVB) copolymers using amines. The modification processes have been executed simultaneously using the microwave-assisted method and the most efficient, conventional one. The greatest total sorption capacities for noble metals were achieved for two resins conventionally modified using ETDA ion exchange resins based on S/DVB matrices. The microwave-modified resins reveal only slightly lower and in some circumstances even better sorption capacity for noble metals than their conventionally-modified equivalents. The differences are discussed by effect of the synthesis method as evaluated using FTIR spectrophotometry.

Microwave-assisted synthesis of anion-exchange resins for sorption of noble metals: how to boost sorption capacity using a proper reaction environment

“…What is interesting, the peaks at 1447 cm -1 (resin 1D), 1447 cm -1 (resin 1S) and 1442 cm -1 (resin 1N), previously recognized as the indicator of the primary amino group -NH 2 [7], differs with intensity from each other. The greatest band may be observed in the spectra recorded for the resin 1N (Fig.…”

“…2) responsible for the -C=N-bonds, created due to the dimethyl formamide [8]. The effect, as described in our previous work [7] will affect final sorption capacity of the resin 1D.…”

“…The situation is completely different during synthesis of the same resin in the conventional conditions. Based on our previous work, [7] the resin 1D, if it had been obtained in course of a regular modification, should reveal twice greater 0.001 M HCl regain. That, without doubts should positively affect its ability to sorption.…”

“…As a result, synthesis was proceeded in N,N-dimethylformamide (DMF) using amines as functionalizing agents. Executed analyzes revealed that the microwaves facilitate creation, instead of amino functional groups, the -C=N-bonds, derived from DMF, resulting with smaller sorption capacity of the received anion exchangers [7,8].…”

“…In our previous work [7] we have reported a rapid procedure of microwaveassisted synthesis of the new amino anion-exchange resins. Proceeded tests on sorption of gold, platinum and palladium revealed that the resins obtained in the microwave field were equal to those, synthesized using the traditional techniques.…”