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A SERIES of magnetite supported silica (Fe 3 O 4 /SiO 2 ) nanoparticles with different Fe 3 O 4 loadings was prepared by co-precipitation method. Structural characteristics of the prepared adsorbents were investigated by X-ray diffraction (XRD), and transmission electron microscope (TEM). The magnetic property was also determined. The adsorption performance of the samples was assessed in the removal of lead ions from aqueous solution. Experiments have been performed to study the effects of several parameters including solution pH, time, initial metal ion concentration and adsorbent weight on the sorption efficiency. The results of the adsorption experiments indicated that the obtained adsorbents have excellent adsorption ability for the removal of lead ions.

The oxidation with Fenton and photo-Fenton reaction in homogeneous system is an effective technology for destruction of a large number of different dyes. The effects of different parameters like the concentrations of H 2 O 2 , the concentration of FeSO 4 , the initial concentration of the dye and the pH of the solution on the degradation of eriochrome Black T (EBT) dye were carried out to investigate the process's optimal operational conditions with the best results at low cost. A suitable operating conditions were selected as: the concentration of H 2 O 2 1.14×10-2 M, the concentration of FeSO 4 1.85×10-4 M, the initial concentration of EBT dye 9.34×10-5 M and the pH equal 3.2 at room temperature. In the given conditions, more than 98.37% of degradation efficiency was achieved within 60 min. of the reaction. Photo-Fenton reaction was investigated and it was found that the degradation efficiency increased from 94 % by Fenton reaction to 99.83% by photo-Fenton reaction at 15 min. The kinetic study indicated that the degradation kinetics of EBT dye followed the second-order kinetics.