Chemical insight into the adsorption of reactive wool dyes onto amine-functionalized magnetite/silica core-shell from industrial wastewaters.

Fe3O4 NPs are synthesized by the co-precipitation technique. Moreover, the pristine was coated by silica layer and then functionalized by 3-aminopropyltrimethoxysilane (APTS). The sample possessed saturation magnetization with value equals 37 emu/g which made them to easily separate using external magnet. FT-IR, TGA, EDX, and VSM confirmed the aminosilane loading. The surface topography and composition were characterized using XRD, TEM, SEM, BJH, and BET methods. Where adsorption capacity of the surface toward the removal of four commercial reactive wool dyes (RD), Itowol black (IB), Itowol Red (IR), Sunzol black (SB), and Lanasol blue (LB) have been investigated. The influence variables such as pH, adsorbent dose, dye concentration, and temperature were calculated. Where experimental results fitted to Langmuir isotherm model with qmax equals 161.29, 151.51, 123.45, and 98.20 mg/g, for IR, LB, SB, and IB respectively. The results showed that the RD adsorption described by pseudo-second-order kinetics. The calculated thermodynamic parameters indicated that RD adsorption onto Fe3O4@SiO2-NH2 was spontaneous and exothermic in nature. The possible mechanisms monitoring RD adsorption on the surface included hydrogen bonding and electrostatic interactions. The reusability of adsorbent carried with four cycles without releasing of magnetite and thus excluding the potential hazardous of nanomaterial to the environment. Graphical abstract.