İbrahim TeğinSelma AkdenizGurbet CanpolatOrhan Acar2025-05-272025-05-272025-05-19Teğin, İ., Akdeniz, S., Canpolat, G., & Acar, O. (2025). Cost-Effective Removal of Cu (II) and Cd (II) from Wastewater Using Walnut Shell-Immobilized Amberlite XAD-4 as a Sorbent. Water, Air, & Soil Pollution, 236(8), 1-19.0049-69791573-2932https://doi.org/10.1007/s11270-025-08129-1https://hdl.handle.net/20.500.12604/8672In this study, a cost-effective and environmentally friendly solid-phase extraction (SPE) method using walnut shell-immobilised on Amberlite XAD-4 (WNS-XAD-4) was developed to pre-concentrate and determine Cu(II) and Cd(II) ions in water samples prior to flame atomic absorption analysis (FAAS). The low-cost adsorbent, prepared by immobilizing waste walnut shells on Amberlite XAD-4 (WNS-XAD-4), was characterized using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Thermal Gravimetric Analysis (TGA), and Brunauer-Emmett-Teller (BET) analysis. Under optimal conditions, the method achieved recoveries of 95.7% for Cu(II) and 100% for Cd(II) using 5.0 mL of 1.5 mol L-1 HNO3 as eluent. The detection limits were found as 0.582 mu g L-1 for Cu(II) and 0.03 mu g L-1 for Cd(II) with preconcentration factors of 10 and 40, respectively. The accuracy of the method was validated using the certified aquatic plant reference material BCR-670 and successfully applied to various real water samples, including those from Lake Van, Billoris Spa, tap water, salt water and wastewater from Siirt, Turkey.eninfo:eu-repo/semantics/openAccessAmberlite XAD-4CadmiumCopperSolid-Phase ExtractionWalnut Shellsjournal-article2368Q2001490221500004Q210.1007/s11270-025-08129-1