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In this investigation, magnetic γ‐Al2O3 nanocomposite polymer particles with epoxide functionality were prepared following a multistep process. The prepared nanocomposite polymer particle was named as γ‐Al2O3/Fe3O4/SiO2/poly(glycidyl methacrylate (PGMA). The surface property was evaluated by carrying out the adsorption study of Remazol Navy RGB (RN), a model reactive azo dye, on both γ‐Al2O3/Fe3O4/SiO2 and γ‐Al2O3/Fe3O4/SiO2/PGMA nanocomposite particles, that is, before and after epoxide functionalization. A contact time, temperature, adsorbent dose, and dye concentration dependent change in adsorption behavior was observed on both nanocomposite particles. The adsorption amount reached equilibrium (qe) value within 5 minutes at the respective point of zero charge (PZC). The adsorption density of RN per unit specific surface area on epoxide functional γ‐Al2O3/Fe3O4/SiO2/PGMA nanocomposite polymer particles (1.30 mg/m2) was higher relative to that on γ‐Al2O3/Fe3O4/SiO2 nanocomposite particles (0.87 mg/m2). The optimum adsorbent dose for obtaining the maximum adsorption density was 0.01 g. Comparatively, Langmuir isotherm model was better to describe the adsorption process and the adsorption process was favorable at low temperature (283 K). Batch kinetic adsorption experiment suggested that a pseudo‐second‐order rate kinetic model is more appropriate. Nanocomposite polymer particles were used as adsorbent up to third cycle with almost 99% adsorption efficiency.

In this investigation magnetic γ-Al2O3 ceramic nanocomposite particles bearing epoxide functionality are prepared following a multistep process. The ultimate nanocomposite particles are named as γ-Al2O3/Fe3O4/SiO2/poly(glycidyl methacrylate (PGMA). The surface property is evaluated by carrying out the adsorption study of Remazol navy (RN), a model reactive azo dye, on both γ-Al2O3/Fe3O4/SiO2 and γ-Al2O3/Fe3O4/SiO2/PGMA nanocomposite particles. The adsorption is carried out at the point of zero charge (PZC) to neutralize the effect of particle surface charge. The adsorption rate is very fast, reached equilibrium (qe) value within five min. Due to mesoporous structure of silica layer γ-Al2O3/Fe3O4/SiO2 nanocomposite particles possessed relatively higher specific surface area and magnitude of adsorption is dependent on the total specific surface area. The introduction of epoxide functionality favored high adsorption capacity in mass per unit surface area. The adsorption process strictly followed Langmuir model. Thermodynamic equilibrium parameters implied that irrespective of surface functionality the adsorption process is spontaneous and exothermic. Pseudo-second-order rate kinetic model is more appropriate to explain the adsorption kinetics.

The nanocomposite particles named as γ-Al 2 O 3 /Fe 3 O 4 /SiO 2 /poly(glycidyl methacrylate) or γ-Al 2 O 3 /Fe 3 O 4 /SiO 2 /PGMA were prepared by multi-step process. At first, γ-Al 2 O 3 nanoparticles were prepared by sol-gel method. Magnetite, Fe 3 O 4, nanoparticles were then precipitated by in situ co-precipitation in presence of γ-Al 2 O 3 particles, followed by incorporation of mesoporous silica layer using Stöber process. Finally, the surface of the γ-Al 2 O 3 /Fe 3 O 4 /SiO 2 nanocomposite particles was modified by seeded polymerization of GMA using free radical polymerization. The surface modification, morphology and size distribution of the prepared nanocomposite particles were confirmed by FTIR, scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The adsorption capacity of γ-Al 2 O 3 /Fe 3 O 4 /SiO 2 /PGMA nanocomposite particles was evaluated using remazol navy RGB (RN-RGB) as a model dye.