Although biochar has been investigated extensively to stabilize soil heavy metals, there were limited investigation on the stabilization of metals by using under natural ageing processes alternate-cooling/heating. In this study, wheat-straw-biochar-treated samples contaminated with Pb(II) ions/PbO subjected 12 h-freeze/12 h-thaw cycles simulating alternate-cooling/heating process. After freeze-...

-Montmoril lonites saturated with small quaternary alkylammonium ions such as tetramethylammonium (TMA) or trimethylphenylammonium (TMPA) are excellent sorbents for aromatic pollutants. In some cases, water inhibits arene sorption, but the inhibition mechanism is not understood completely. The objectives of this study were to determine whether arenes interact with adsorbed TMA and TMPA ions and...

The magnetic field dependence of the NMR spin-lattice relaxation t ime of water protons in intact bovine chromaff in vesicles has been studied over the range 1.00--23.49 kG. The T~ relaxation time shows a dispersion at field values near 20 kG. The observed pro ton resonance arises mainly from solvent protons (~H20), but the relaxation rate, which is a weighted average over all sites with which ...

Locations of Cu2+ ion in Cu(2+)-adsorbed montmorillonite have been studied by electron paramagnetic resonance (EPR), supplemented by X-ray diffraction (XRD) and differential thermal analysis (DTA). In the EPR spectra of Cu(2+)-adsorbed montmorillonite, three signals, corresponding to Cu2+ ion, have been simultaneously recorded. Some Cu2+ ions seemed to replace the original interlayer metal cati...

Septic tank effluent is inherently high in sodium ions relative to divalent cations (high sodium adsorption ratio). The disposal of septic tank effluent to the soil will cause the sodium ions to disperse the clay colloids, resulting in a physical blocking of the soil pores. Hydraulic conductivity will be reduced and the effluent will fail to dissipate into the soil profile. In designing the dis...

In this article, we report the family of robust layered sulfides K(2x)Mn(x)Sn(3-x)S(6) (x = 0.5-0.95) (KMS-1). These materials feature hexagonal [Mn(x)Sn(3-x)S(6)](2x-) slabs of the CdI(2) type and contain highly mobile K(+) ions in their interlayer space that are easily exchangeable with other cations and particularly strontium. KMS-1 display outstanding preference for strontium ions in highly...

The yield response of various crops to salinity under field conditions is affected by soil processes and environmental conditions. The composition of dissolved ions depend on soil chemical processes such as cation or anion exchange, oxidation-reduction reactions, ion adsorption, chemical speciation, complex formation, mineral weathering, solubility, and precipitation. The nature of cations and ...

Call a random partition of the positive integers partially exchangeable if for each finite sequence of positive integers n l , . . . , nk, the probability that the partition breaks the first nl + . . . § nk integers into k particular classes, of sizes nl . . . . , nk in order of their first elements, has the same value p(na . . . . . nk) for every possible choice of classes subject to the sizes...