In this study, the potential of cross-linked poly(styrene-co-methacrylic acid) (PSMAA) as a support material for the immobilization of walnut shells was systematically investigated. The resulting immobilized walnut shell sorbent (WNS-PSMAA) was subsequently used for the extraction of Cu(II) and Cd(II) ions from spiked aqueous solutions. The removal efficiency was evaluated by analysing the influence of various experimental parameters such as pH of the solution, concentration of the eluent, flow rate, solution volume, mass of the sorbent, matrix interference and reusability. Under optimized conditions, the method enabled a 60-fold enrichment for Cu(II) and a 10-fold enrichment for Cd(II) with recoveries of 100.00% ± 2.30 and 99.89% ±2.83, respectively, confirmed by triplicate analyzes with a confidence level of 95. Method accuracy was verified by employing the certified reference material for aquatic plants (BCR-670). Consequently, the prepared low-cost adsorbent was successfully used for the determination of the mentioned metals in various real samples such as Van Lake water, Billoris Spa water and tap, salty, wastewater of Siirt (Türkiye).
Teğin et al. (2026) studied this question.