CoFe 2 O 4 and NiFe spinel ferrites were obtained by microwave-assisted sol–gel combustion synthesis using three different types of chelating/combustion agents: maleic acid, citric urea. The nanomaterials produced characterized from the structural, morphological, textural, magnetic viewpoints. prepared employed as adsorbents for removal Orange-II dye synthetic wastewaters. nickel ferrite sample...