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Magnetic photocatalyst [magnetic@silica@zinc manganate, Fe3O4@SiO2@ZnMn2O4] (MZMO) and [magnetic@silica@zinc manganate@copper tetra hydroxyl phenyl porphyrin, Fe3O4@SiO2@ZnMn2O4@CuIITHPP] (MZMOCuP) nanocomposites were prepared using green synthesis method and characterized by means of Fourier transform-infrared, scanning electron microscope, energy-dispersive X-ray spectroscopy, X-ray diffraction, vibrating sample magnetometer (VSM) and ultra-violent-diffuse reflectance spectroscopy techniques. The magnetic properties of the synthesized samples were measured by a VSM with maximum saturation magnetization values of 10 and 8 emu g−1 for MZMO and MZMOCuP nanocomposites, respectively. UV-diffuse reflectance spectroscopy data of MZMOCuP indicate the red shift of the absorption edge and reduction of the band gap from 1.4 to 1.1 eV in comparison with MZMO. The nanocomposite of MZMOCuP showed excellent photocatalytic activity for photodegradation of methylene blue (MB) in aqueous solution under visible-LED light irradiation. The degradation of MB was monitored by UV–Vis spectrophotometer. Maximum degradation of 98% for MB was obtained in the presence of MZMOCuP nanocomposite as the photocatalyst and under 180 min irradiation of 3 W blue LED light. The recovery of the photocatalyst was easily performed by using an external magnetic field.

Fe3O4@SiO2@THPP (MSTHPP) nanocomposite was prepared as an adsorbent for the removal of lead ions. The structural characteristics of thisnanocomposite were determined using Fourier transform-infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy, x-ray diffraction, vibrating sample magnetometry (VSM), and N2 adsorption-desorption analyses. SEM images showed that the magnetic nanoparticles have uniform morphologies with a mean size of 20 nm. The magnetic properties of the synthesized nanocomposite were measured on a VSM with maximum saturation magnetization values of 40 emug-1 and 10 emug-1 for Fe3O4@SiO2 and MSTHPP nanocomposites, respectively. MSTHPP has been efficiently used to remove lead ions from aqueous solutions. After the lead sorption process, the nanocomposite was magnetically separated from the mixture and showed good reusability. The effects of pH, contact time, adsorbent dosage and initial concentration of lead in the removal of lead were investigated. Optimization of the parameters was performed by using Taguchi design method to obtain the maximum removal efficiency. The optimized condition can be achieved when pH, contact time, adsorbent dosage and initial concentration of lead are 5.3 min, 30 min, 50 mg, 20 ppm, respectively. The M, MS, and MSTHPP lead removal efficiency was found to be 18%, 25%, and 97%, respectively.

Magnetic photocatalyst (magnetite@silica@titania@copper(II) 5,10,15,20-tetrakis(4-(hydroxyl)phenyl) porphyrin, Fe3O4@SiO2@TiO2@CuIITHPP) (MSTCuP) has been synthesized, characterized, and utilized to degrade the methylene blue (MB) under a visible LED light irradiation. The structural characteristics of the MSTCuP were determined using FT-IR, SEM, EDX, XRD, BET and VSM techniques. The magnetic properties of the synthesized samples were measured by a vibrant sample magnetometer (VSM) with maximum saturation magnetization values of 10 and 8 emu g−1 for Fe3O4@SiO2@TiO2 (MST) and Fe3O4@SiO2@TiO2@CuIITHPP (MSTCuP) nanoparticles respectively. UV-DRS data show the red-shift of the absorption edge and decrease of the band gap to 1.8 eV. The degradation of MB was monitored by UV–Vis spectrometry. Maximum degradation of %98 for MB dye was attained by the use of MSTCuP nanocomposites as the catalyst and under 180 min irradiation of blue LED light. After three 180 min photocatalytic runs for MB degradation, the catalyst still showed high activity. The recovery of the catalyst was easily performed by applying the external magnetic field. The efficiency of green, red and yellow Vis-LED light sources for the photocatalytic degradation of MB was also investigated. The degradation of MB using MSTCuP nanocomposite was found to follow the pseudo-first-order kinetic.

The oxidation of benzyl alcohols has been studied in the presence of isobutyraldehyde as co-catalyst, molecular oxygen as oxidant and copper (II) meso-tetra phenyl porphyrin (CuTPP) as catalyst. The CuTPP catalyst exhibits good activity and high selectivity under mild conditions. The effects of temperature and solvents have also been investigated in this catalyst system.