In this research, Keggin-type polyoxometalate, H5PMoV2O40 (denoted as PMoV) was immobilized on modified NiFe2O4 nanoparticles to produce a magnetically separable catalyst. This catalyst was characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), cyclic voltummetry (CV), energy dispersive X-ray (EDX) and UV-vis diffuse reflectance spectroscopy (UV-DRS). The catalytic activity of synthesized catalyst in oxidation of dibenzothiophene (DBT) to dibenzothiophene sulfone (DBTO2) was investigated using H2O2 as an oxidant and acetonitrile as an extractant. The catalyst could be readily separated from the catalytic system using the magnetic field; and loss of activity was negligible when the catalyst was recovered in five consecutive runs. The effects of main process variables including H2O2 amount (mmol), reaction temperature (°C) and reaction time (min) were analyzed by response surface methodology (RSM) based on the central composite design (CCD). The optimal condition for conversion of DBT was found to be H2O2 2.8 mmol, reaction temperature 42°C and reaction time 57 min for 0.1 g of catalyst dosage. The conversion of DBT to DBTO2 under optimized conditions was 85.9 %. Moreover, the dibenzothiophene sulfone product was characterized by NMR, FT-IR, Mass and GC analysis.

In this work, we prepared the nafion/montmorillonite/HETEROPOLYACID nanocomposite membranes for direct methanol fuel cells (DMFCs). The analyses, such as X-ray diffraction (XRD), Fourier transform infrared (FTIR), and scanning electron microscopy (SEM), were conducted to characterize the filler dispersion and membrane structure in prepared nanocomposite membranes. XRD patterns of nafion-CsPW-MMT nanocomposites membranes showed the exfoliated structure of membranes by adding MMT and CsPW. SEM-EDXA results showed proper dispersion of nanoparticles in the membrane matrices. Addition of CsPW-MMT to nafion membranes increases water uptake and IEC due to the increase of hydrophilic groups in membranes. The proton conductivity results showed that proton conductivity increases by increasing amount of CsPW and decreasing of clay content in the membrane. Methanol crossover through polymer electrolyte membranes is a critical issue and causes an important reduction of performance in DMFCs. The developed intercalated nafion/CsPW/MMT nanocomposite membranes have successfully improved the membrane barrier properties due to the unique feature of MMT which contributed to the formation of a longer pathway towards methanol across the membrane. The lowest methanol crossover of the developed membranes in this study was 1. 651×10-6 cm2s-1 Error! Digit expected. which is lower than re-cast nafion membrane (2. 078×10-6 cm2s-1). The methanol permeability was significantly reduced by the incorporation of MMT and increased by addition of CsPW in the nafion membrane. Finally, according to the selectivity results, the nafion-MMT-CsPW nanocomposite membrane with MMT mass fraction of 2. 5 % and CsPW mass fraction of 8 % shows the best membrane selectivity and this nanocomposite membrane could be suitable for application in DMFCs.

Nanoclay-supported Preyssler HETEROPOLYACID as a new and effective nanocomposite was used to improve the compressive strength of concrete. The cement pastes used in this study were a mix of water, ordinary Portland cement and nanoclay-supported Preyssler HETEROPOLYACID. The nanoclay-supported Preyssler were added into the concrete with different concentrations of 1, 2, 3, 4 and 5% by the weight of cement amount. Water/cement ratio was 0. 35 and the dimension of the cubic samples was 15 ×15 ×15 Cm. Compressive strength tests were done on hardened specimens. The obtained results revealed that the addition of nanoclay-supported Preyssler HETEROPOLYACID into the concrete samples led to increase in compressive strength of concrete specimens equal to 23. 2% at 28 days for dosage of 3%.

Dawson HETEROPOLYACID, H6 [P2W18O62], was chemically anchored to the amine-functionalized nanosilica surface in different loadings. The synthesized nanocomposite was characterized by FT-IR spectroscopy and N2 adsorption experiments. The preservation of the structure of the Dawson and dispersion of the cluster on the support were verified on the basis of the spectroscopic data.The photocatalytic degradation efficiency of the synthesized nanocomposites was studied using an aqueous solution of malachite green dye as a model water pollutant. The mineralization of dye contents was investigated in different loadings from 10 to 30 % at room temperature. Decolorization was observed in shorter time using 30 % loading.The photocatalyst was reusable after the filtration and remained active even after being washed with hot water, which confirm its attachment firmly to the surface of amine-functionalized nanosilica.

A novel nanophotochromic film consisting of Au nanoparticles and Wells–Dawson-type HETEROPOLYACID, [H6P2W18O62], was prepared by combination of sol–gel and photoreduction method. This film was characterized by UV–visible spectroscopy, particle size distribution, Field emission scanning electron microscopy, and energy dispersive spectroscopy analysis. For the preparation of Au nanoparticles, HETEROPOLYACID, [H6P2W18O62] was used in form of composite film as a green reductant and stabilizer. Au nanoparticles with particle size in the range of 10–20 nm were synthesized and monodispersed in the nanocomposite using dip coating method. The photocatalytic activity of this composite film was studied in the decolorization of methyl orange (MeO) and methyl red (MR) as carcinogenic pollutant dyes using UV irradiation. The pseudofirst order rate constants was established and calculated for these reactions. Comparison of this composite film with the prepared composite by Preyssler HETEROPOLYACID disclosed that the structure of HETEROPOLYACID can affect loading amount of Au nanoparticles.

Wells–Dawson tungsten HETEROPOLYACID (H6P2W18O62) has been applied as an effective heterogeneous catalyst for one-pot synthesis of spiro [4H-pyran-3, 3’-oxindoles] via reaction of various isatins, malonitrile and 1, 3-dicarbonyl compound in water. The corresponding products were obtained in high yields. The catalysts were easily recycled and reused without loss of their catalytic activity.

Preyssler-type HETEROPOLYACID supported on TiO2 nanoparticles has been explored as an efficient catalyst in selective oxidation of primary aromatic amines to azoxy derivatives using trans-3,5-dihydroperoxy-3,5-dimethyl-1,2-dioxolane as oxidant. The reactions proceeded smoothly under mild and green ultrasound-accelerated conditions to afford the products in high yields. The catalyst recovered from the reaction mixture exhibits long-term stability with no significant drop in its catalytic activity.

This is a report of an efficient, clean and facile method for the synthesis of 1,4-dihydropyrano[2,3-c] pyrazole and pyrano[2,3- d]pyrimidine derivatives via three-component one-pot condensation of 3-methyl-1-phenyl-1H-pyrazol-5(4H)-one or barbituric acid, aldehydes and malononitrile in the presence of a catalytic amount of preyssler type HETEROPOLYACID as a green and reusable catalyst in water or ethanol under refluxing conditions.