Synthesis, characterization and application of a modified acrylamide–styrene sulfonate resin and a composite for sorption of some rare earth elements

Abstract

The present work was attempted to prepare three new sorbents including a poly(acrylamide–sodium styrene sulphonate) P(AM–SSS) hydrogel, a poly(hydroxamic acid–sodium styrene sulphonate) P(HA–SSS) modified polymeric resin and a poly(acrylamide–sodium styrene sulphonate–silicon oxide) P(AM–SSS–SiO₂) composite by irradiation template polymerization. The effective reaction parameters such as absorbed dose (kGy), crosslinker and monomer concentration, and the polymer/monomer ratio, which affect the degree of template polymerization, were optimized to get the maximum conversion percentage and high capacity. The physico-chemical swelling behavior of the hydrogel was higher than the resin and the composite. Modification of the hydrogel into modified polymeric resin was achieved by using hydroxylamine hydrochloride. The modification process is indicated by FTIR characteristic absorption bands of –O–H and >N–O– groups of the hydroxamic groups. Furthermore, an organic–inorganic composite was prepared by introducing silica into the polymer, which is indicated by FTIR characteristic adsorption bands of the silica network at 1209 cm⁻¹ and 960 cm⁻¹. The application of the prepared sorbents for removal of La³⁺, Ce³⁺, Nd³⁺, Eu³⁺ and Pb²⁺ from aqueous solution was investigated by a batch technique. Various factors influencing the sorption behaviors were tested such as shaking time, pH and initial metal ion concentration. The obtained results showed that the prepared composite has better uptake percentage and higher capacity than the resin and the hydrogel and the sorption efficiency of metal ions towards the three adsorbent materials obeys the order La³⁺ > Ce³⁺ > Nd³⁺ > Eu³⁺ > Pb²⁺.