الفهرس 
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Abstract
In this work, Fe3O4 was prepared by three different techniques namely; coprecipitation, hydrothermal and sonochemical with magnetic saturation values of 60, 52, and 27 emu/g, respectively. Thus, the co-precipitated sample was functionalized by mono- and di-aminosilane coupling agents (ASC). The loading of ASC onto Fe3O4 surface was carried out in different polar solvents. Moreover,the pristine coated by silica layer and then functionalized by APTS. The sample possessed saturation magnetization with 37 emu/g made them easily separation using external magnet. FT-IR, TGA, EDX and VSM techniques confirmed the aminosilane loading. The surface topography and composition were characterized using XRD, Raman, TEM, SEM, BJH, and BET methods. where adsorption capacity of the functionalized surface toward the removal of four commercial reactive wool dyes (RDs), Itowol black (IB), Itowol Red (IR), Sunzol black (SB) and Lanasol blue (LB) and anionic dyes Eosin-Y (EY) as a model have been investigated. The influence variables such as; synthesis methods, type of amino silane, pH, adsorbent dose, dye concentration, and temperature have been investigated. where experimental results fitted to Langmuir isotherm model with qmax equals 38.32 mg/g. 98.20 mg/g, 161.29 mg/g, 123.45 mg/g and 151.51 mg/g for EY, IB, IR, SB and LB, respectively. The results showed that the RDs and EY adsorption described by pseudo second-order kinetics. The calculated thermodynamic parameters indicated that RDs adsorption onto Fe3O4@SiO2–NH2 was spontaneous and exothermic in nature. where adsorption of EY onto Fe3O4-NH2 was spontaneous and endothermic in nature. The possible mechanisms monitoring RDs and EY adsorption on the surface included hydrogen bonding and electrostatic interactions. The reusability of adsorbent carried with four cycles without releasing of materials and thus excluding the potential hazardous of nanomaterial to the environment.