Deactivation of cobalt and nickel catalysts in Fischer-Tropsch synthesis and methanation JAVIER BARRIENTOS Akademisk avhandling som med tillstånd av KTH i Stockholm framlägges till offentlig granskning för avläggande av teknologie doktorsexamen fredagen den 23 september kl. " True wisdom comes to each of us when we realize how little we understand about life, ourselves, and the world around us....

Nanocomposites are formed by joining two or more materials, at least one of which must have a size in the nanometer range (1 nm -100 nm). In this study, cobalt ferrite-silver nanocomposite was prepared with green synthesis approach. The aim to combine magnetic properties cobalt-ferrite nanoparticles both antimicrobial and conductivity silver nanoparticles. Thus, material can be used for biologi...

Magnetic properties of single crystals of cobalt and substituted cadmium-cobalt spinel ferrites are presented under high magnetic field up to 180 kOe in the 4.2-300 K temperature range for five substitution rates. The easy direction of magnetization is [loo] whereas abrupt field transitions are observed below 150 K for the [Ill] direction. The influence of the cadmium substitution on the molecu...

Nanocrystalline nickel ferrite (NiFe2O4) has been synthesized from a stoichiometric mixture of oxides NiO and α-Fe2O3 in a high energy planetary mill. A post milling annealing at 350 °C was used to improve the solid state reaction. The obtained powders were investigated by X-ray diffraction, magnetic measurements, scanning electron microscopy, X-ray microanalysis, differential scanning calorime...

We report on the frequency (f1⁄420 Hz–1 MHz) and temperature (T1⁄4300–600 K) dependent electrical properties of gadolinium (Gd) substituted cobalt ferrite (CoF2 xGdxO4 (CFGO); x1⁄40.00–0.40). Gd-substituted cobalt ferrites crystallize in cubic inverse spinel phase. CFGO materials exhibit lattice parameter expansion from 8.373 Å (x1⁄40.0) to 8.422 Å (x1⁄40.4) due to the larger ionic radius of Gd...

The dependence of the magnetostrictive properties of cobalt ferrite on the size distribution of thepowder used in deriving the samples from traditional ceramic approach is presented. Sample obtained by combining the smallest and largest particle size distributions gave the highestmagnetostriction and strain sensitivity (216 ppm and 1.34 nm/A, respectively), for measurementin parallel direction ...

Spent Nickel cadmium batteries are classified as hazardous waste due to the presence of toxic cadmium in high concentration. Recycling of metal value by environmentally friendly process is the best option to obtain economical advantage and prevent environmental pollution. In the present investigation, a metal separation scheme is proposed for recovery of cadmium, nickel and cobalt from the leac...