Nanocrystalline NiFe2O4 particles were prepared by conventional sol-gel, citrate-nitrate sol-gel combustion and co-precipitation methods. The synthesized samples were annealed at 1000 ºC for two hours and structural, chemical, morphological, optical and magnetic properties of nickel ferrite were investigated. The structural properties were investigated by X-ray diffraction (XRD) technique which confirmed the formation of single phase NiFe2O4 particles derived by the three methods. The chemical properties were analyzed by Fourier transform infrared (FT-IR) spectroscopy which confirmed the corresponding vibration modes in the samples. The optical properties were studied by UV-Vis spectroscopy. The morphological study of the as-synthesized samples was carried out by scanning electron microscopy (SEM). SEM images showed the agglomerated nanoparticles of NiFe2O4. The magnetic properties were investigated by vibrating sample magnetometer (VSM), which showed that the calcined samples exhibited typical magnetic behavior.
The present study was focused on the technical feasibility of using immobilized hybrid biomass of Pleurotos sajor-caju and sunflower for Pb(II) removal from the contaminated water. After preliminary evaluation, it was found that immobilized hybrid biomass of Pleurotos sajor-caju and sun-flower effectively removed Pb(II) from wastewater at pH 4.5. The effect of various experimental parameters on Pb(II) uptake by hybrid biosorbent was systematically evaluated in a batch biosorption system. The optimized biosorbent dose, contact time, initial metal concentration and temperature were 0.05 g/100 cm 3, 180 min, 800 mg/dm3 and 60 °C. Dynamics of the adsorption process were studied, and the values of rate constants of pseudo first order and pseudo second order kinetic models were calculated. Equilibrium isotherms for the adsorption of Pb(II) were analyzed by the Langmuir and Freundlich isotherm models. The sorption of Pb(II) followed the pseudo second order kinetic model. The Langmuir sorption isotherm fitted well to Pb(II) concentration data. The results revealed that this new hybrid biosorbent system was a promising candidate for eliminating Pb(II) from contaminated aquatic environment.
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Our object in this paper is to study the generalization of Borut Zalar result in [1] on Jordan centralizer of semiprime rings by prove the following result: Let R be a prime of characteristic different from 2, and U be a Jordan ideal of R. If T is an additive mapping from R to itself satisfying the following condition T(ur + ru) = uT(r) + T(r)u, then T(ur) = uT(r), for all r is an element of R, u is an element of U.
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