The adsorption behavior of natural Jordanian zeolites with respect to Cd(2 + ), Cu(2 + ), Pb(2 + ), and Zn(2 + ) was studied in order to consider its application to purity metal finishing drinking and waste water samples under different conditions such as zeolite particle size, ionic strength and initial metal ion concentration. In the present work, a new method was developed to remove the heavy metal by using a glass column as the one that used in column chromatography and to make a comparative between the batch experiment and column experiment by using natural Jordanian zeolite as adsorbent and some heavy metals as adsorbate. The column method was used using different metal ions concentrations ranged from 5 to 20 mg/L with average particle size of zeolite ranged between 90 and 350 mum, and ionic strength ranged from 0.01 to 0.05. Atomic absorption spectrometry was used for analysis of these heavy metal ions, the results obtained in this study indicated that zeolitic tuff is an efficient ion exchanger for removing heavy metals, in particular the fine particle sizes of zeolite at pH 6, whereas, no clear effect of low ionic strength values is noticed on the removal process. Equilibrium modeling of the removal showed that the adsorption of Cd(2 + ), Cu(2 + ), Pb(2 + ), and Zn(2 + ) were fitted to Langmuir, Freundlich and Dubinin-Kaganer-Radushkevich (DKR). The sorption energy E determined in the DKR equation (9.129, 10.000, 10.541, and 11.180 kJ/mol for Zn(2 + ), Cu(2 + ), Cd(2 + ) and Pb(2 + ) respectively) which revealed the nature of the ion-exchange mechanism.

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In this paper, the effects of alignment, pH, surfactant and solvent on heat transfer nanofluids containing Fe2O3 and CuO nanoparticles are studied and analyzed. The microscope images show that Fe2O3 could form some kind of alignment spontaneously in water even without external magnetic field. With the addition of external magnetic field, the alignment is strengthened. In water, the magnetic particle agglomeration to larger size occurs easily, which makes the directional alignment much faster and easier. Ethylene glycol solvent and chemical surfactant sodium dodecyl benzene sulfonate, NaDDBS could separate the Fe2O3 and CuO nanoparticles well in the fluids and avoid possible aggregation. Therefore, magnetic alignments are hard to observe. The measured thermal conductivities of each individual sample coincide with the microscope images and assumptions. In addition, pH values of Fe2O3 and CuO nanoparticles are measured and it has been determined that at those pH values, thermal conductivities of those nanoparticles would not be influenced according to the Derjaguin–Landau–Verwey–Overbeek (DLVO) theory. The highlight of this paper is that our microscope images could well explain most of the literature data and conclusions and may open new door to better understanding fundamental nature of nanofluids.

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Purpose -The purposes of this paper are to prepare the carbon nanotube (CNT) grease, to contrast the tribology properties of the CNT grease with the original grease and to find the lubricating mechanism of the CNT grease. Design/methodology/approach -The CNTs (single-wall and multi-wall) are added into the polyalphaolefin oils (DURASYN_166) to form stable and homogeneous CNT grease with potential heat transfer, conductive and lubricative properties. The friction of this new type of CNT grease was determined by wear experiments under three conditions: dry friction, with the base oil grease and with the CNT grease. Findings -The research is about the tribological properties of CNT greases; it shows better lubricating performance and wear resistance than the base oil grease. The performance improvement of CNT grease is owing to the unique hexagonal structure and the high thermal conductivity of CNTs. Originality/value -The paper documents that CNTs can obviously improve the lubricating effect of grease, and the lubricating mechanism of the CNT grease is also discussed.

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