in this study, the adsorption of hexavalent chromium and zinc ions from the solution is investigated by raw red mud and mechanical-chemical activated red mud along with the possibility of selective reclamation of these ions from the solution. the mechanical-chemical activation of red mud was done by employing high-energy milling and subsequent acid treatment with hno3. raw red mud (rrm) and mec...

polypyrrole (ppy/cl) and polyaniline (pani/cl) synthesized chemically onto sawdust (sd)was used for removal of thiocyanate (scn-) ions from aqueous solutions. the effect of someimportant parameters such as ph, initial concentration, sorbent dosage, and contact time onuptake of scn- was investigated. ppy/sd was found to be much more effective sorbent thanpani/sd for uptake scn- from aqueous solu...

This investigation was undertaken to determine whether desorption hysteresis effects were dependent upon methods used in obtaining desorption data. Adsorption-desorption isotherms were obtained for two organophosphorus insecticides in aqueous suspensions of a clay, a sandy loam, and an organic soil. Desorption isotherms were obtained using both the consecutive desorption method and the dilution...

The desorption characteristics of lead in two variable charge soils (one developed from Arenaceous rock (RAR) and the other derived from Quaternary red earths (REQ)) were studied, and the effects of pH value, organic acid, and competitive ions were examined. Desorption of Pb(2+) decreased from nearly 100.0 to 20.0% within pH 1.0-4.0 in both soils, and then the decrease diminished at pH > 4.0. O...

Hexagonal boron nitride (h-BN) is known as an effective additive to improve the hydrogen de/absorption properties of hydrogen storage materials consisting of light elements. Herein, we report the unique hydrogen desorption properties of LiAlH4/h-BN composites, which were prepared by ball-milling. The desorption profiles of the composite indicated the decrease of melting temperature of LiAlH4, t...

land treatment method of municipal and industrial wastewaters for utilization of nutrients in the wastes for raising useful crops and tertiary(or advanced) treatment of the water for improving stream quality or to recharge falling water tables is increasing in some parts of the world, particulary in the arid area. as emphasis in this type of treatment method and prevention of surface and underg...

Measures of desorption are currently considered important as potential surrogates for bioaccumulation as measures of the bioavailability of sediment-sorbed contaminants. This study determined desorption rates of four laboratory spiked compounds, benzo[a]pyrene (BaP), 2,4,5,2',4',5'-hexachlorobiphenyl (HCBP), 3,4,3',4'-tetrachlorobiphenyl (TCBP), and pyrene (PY), to evaluate the effect of sedime...

Methods by which experimental measurements of thermal desorption can be applied in astrophysical environments have been developed, using the sublimation of solid methanol as an example. The temperature programmed desorption of methanol from graphitic, amorphous silica and polycrystalline gold substrates was compared, with the kinetic parameters of desorption extracted by either a leading edge a...

The desorption of molecular species from ice mantles back into the gas phase in molecular clouds results from a variety of very poorly understood processes. We have investigated three mechanisms; desorption resulting from H2 formation on grains, direct cosmic ray heating and cosmic ray induced photodesorption. Whilst qualitative differences exist between these processes (essentially deriving fr...

H.-R. Schulten and W. D. Lehmann Institute of Physical Chemistry, University of Bonn, Wegeierstraße 12, D-5300 Bonn Z. Naturforsch. 83 b, 770-781 (1978); received March 21, 1978 Field Desorption Mass Spectrometry, a-Amino Acid Methionine The fragmentation of methionine in field desorption mass spectrometry has been studied. Decomposition mechanisms are described which are based on stable isotop...