Synthesis of cross-linked sulfonated poly(ether ether ketone) and its use for Pb²⁺ and ¹³⁷Cs removal from aqueous solution

Sulfonated ion irradiated (H⁺ and He²⁺) PEEK films were synthesized with a range of cross-linking density and a variety of sulfonation degrees. Batch adsorption experiments were carried out at an initial pH of 6.0 ± 0.2, initial concentrations of Pb²⁺ and ¹³⁷Cs ions of 10.0 mg L⁻¹ and 5500 Bq L⁻¹, respectively. The maximum adsorption capacity was 60 mg g⁻¹ for Pb²⁺, and the distribution coefficient reached 6200 cm³ g⁻¹ for ¹³⁷Cs. The results indicated that sulfonation could be used to recycle low cross-linked PEEK and prepare efficient adsorbents to remove toxic Pb²⁺ and ¹³⁷Cs from polluted aqueous solutions.