In this study the origin of ferromagnetism in ZnO-based bulk systems has been investigated using Nidoped ZnO samples, Zn 1−x Ni x O with 0.25 ≤ x ≤ 0.50, prepared by solid-state reactions. The structural characterizations indicated that the Ni 2+ ions almost uniformly distributed in all the samples, and the samples have hexagonal wurtzite structure; however, when x is increased toward 0.50, a new NiO phase is formed. A ferromagnetism (FM) has been observed for all the samples at and below the room temperature. In other words, the room temperature results of (M-H ) curves show that the FM observed is intrinsic for all the Ni-doped ZnO samples. However, the saturated magnetizations decrease gradually with increasing Ni concentration. This indicates that, in addition to FM, the excessive doping of Ni in ZnO also causes an antiferromagnetic (AFM) contribution which increases with increasing Ni amount. This result is also supported by the magnetization against temperature measurements. Furthermore, the trend of the acsusceptibility (χ) versus temperature curves, measured under an ac-magnetic field of 100 Oe, also support our conclusion about the antiferromagnetic contribution to ferromagnetism in our samples.A. Ekicibil ( ) ·

In this study, physical, mineralogical and morphological characteristics of mechanically treated fly ashes are investigated. The compositional analysis of the raw fly ash was determined using X-ray fluorescence (XRF) technique. The XRD patterns reveal that the main phase quartz along with mullite and anhydrite. The raw fly ash was also wet ground using a laboratory mill, for several different times (from 2 to 16 hours) in order to examine how the grinding increases the activity of the fly ash. The ground fly ash was characterized for (i) particle size distribution: laser diffraction method, (ii) specific surface area: BETmethod, (iii) crystalline structure: X-ray diffractometer, and (iv) morphology of particles: scanning electron microscope. According to physical characterization, fineness increasing of samples with grinding time was observed, but loss of effectiveness occurred for grinding time longer than 12 hours. In addition, the unmilled fly ash showed lower specific surface area, due to the presence of cenospheres in the original fly ash. Only a little change in crystalline structure of fly ashes was observed when grinding and there were changes in the area and height of each diffraction peak.

This is a 'preproof' accepted article for Clay Minerals. This version may be subject to change during the production process.

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In present study, the adsorption behaviour of surfactants which are cationic (hexadecyltrimethylammonium bromide, HTAB), anionic (sodium dodecyl sulphate, SDS) and non-ionic (Triton X100, TX100) onto naturally hydrophobic talc were investigated. In this scope, a series of batch adsorption tests at natural pH were performed to determine adsorption isotherms and zeta potential (ZP) measurements of the ionic and non-ionic surfactants onto talc surfaces were measured using electrophoresis technique. To understand the mechanism of the adsorption process, the adsorption of ionic and non-ionic surfactants was studied as a function equilibrium concentration (mol/L). The amount of maximum adsorption of the surfactants onto talc are ordered as in the following: TX100 (9.0x10 5 mol/m 2)HTAB (8.5x10 5 mol/m 2) > SDS (5.32x10 5 mol/m 2). Even though both the SDS and talc have negative surface charge, SDS can adsorb onto talc. Moreover, a good correlation was obtained between the adsorption isotherms and the zeta potential curves. Considering their adsorption isotherms, the ionic surfactants were showed different adsorption behavior concerning the non-ionic surfactant molecules. The adsorption isotherms of TX-100 and SDS increase rapidly in a narrow concentration range until the plateau region, while such a sharp increase does not appear for HTAB. The maximum adsorption amount of TX-100 and HTAB is greater than SDS. The results indicate that hydrophobic interaction and hydrogen bonding play a decisive role on the adsorption of non-ionic and anionic surfactants onto talc a naturally hydrophobic mineral, whereas electrostatic interaction becomes more important in the adsorption of cationic surfactant.

The structural, electric, and magnetic properties of La 1Àx Na x MnO 3 (0.05 £ x £ 0.35) compounds have been investigated. The compounds were prepared by a standard sol-gel method then sintered at 1400°C for 24 h. The crystal structures were orthorhombic (Pbnm) for all Na concentrations, and the unit cell volumes, determined from the x-ray diffraction data, tended to decrease with increasing Na content. The high-temperature-sintering process resulted in a grainy structure with grain sizes of 5-30 lm. The Curie temperature (T C ) increased with increasing Na concentration up to x = 0.20, then decreased with further increase in Na concentration. The maximum magnetic entropy change (ÀDS M ) under a field change of 1.6 T was calculated to be $3 J/kg K for the sample containing 15% Na.

The papers on magnetic modification processes were firstly published about synthetic zeolites and studies continue Petridis et al [1], Čapek et al [2]. The literature review, which we have done up to now, shows that there is no study about the magnetic modification process for 13X zeolite or that we haven't found one even if there were one. For this reason, this study was realized on magnetic modified 13X zeolite about the magnetical modification by using magnetite obtained from Divriği region, Turkey. After the modification process, samples were characterized by XRD, XRF, SEM, EDX, VSM. Then, ion exchange and magnetic properties of unmodified and modified zeolites were compared with each other. According to these findings, modified zeolites have better ion exchange and magnetic properties than the others.

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