The xanthine-based magnetic supported iron oxide (Fe3O4@SiO2@CPTMS@ XAN =XAN) was prepared, characterized and used as an efcient adsorbent for removal of the Cd(II), Ni(II) and Pb(II) ions from aqueous solution. The ICP measurement showed that the maximum adsorption capacity of the XAN adsorbent for the Cd2+ ion was higher than for the lead and nickel ions. Therefore, the corresponding xanthine-based adsorbent-Cd complex (Fe3O4@SiO2@CPTMS @ XAN@Cd=XAN-Cd) was also prepared, characterized and used as a capable heterogeneous nanocatalyst for the green synthesis of diverse indazolophthalazinetriones from the reaction of phthalhydrazide, aldehydes, dimedone and the XAN-Cd catalyst in H2O-EtOH at 80 °C in good to high yields. The adsorbent, catalyst and indazolophthalazinetriones were characterized by diferent techniques such as the FT-IR, 1H NMR/13C NMR spectra, TGA/DTA, VSM, ICP, XRD SEM, EDX and XPS. In addition, a positive enthalpy in the range of 2.43 to 3.51 showed that the adsorptions are physical; therefore, the metal ion pollutants can easily be separated from the adsorbent by back washing which is very promising and new news for the world’s environmental industry. Also, the adsorbent can be used many times and a large amount of pollutant can be removed with a small amount of adsorbent which is cost-efective as well.
