Thermodynamics of potassium (K) exchange using a kinetics approach was investigated in Ca-saturated samples from the Ap and B21t horizons of a Matapeake soil from Delaware. Kinetics of adsorption and desorption were determined at temperatures of 0, 25, and 40°C on each soil horizon using a miscible displacement technique. Energies of activation for adsorption and for desorption (£„ and Ed, resp...

In this work the feasibility of employing calcareous soil to remove lead (II) ions from its aqueous solutions was investigated under batch mode. The influence of solution pH, sorbent dose, initial lead (II) concentration, contact time, stirring rate and temperature on the removal process were investigated. The lead adsorption was favored with maximum adsorption at pH 6.0. Sorption equilibrium t...

Calixarenes grafted on silica are energetically uniform hosts that bind aromatic guests with 1:1 stoichiometry, as shown by binding energies that depend upon the calixarene upper rim composition but not on their grafted surface density (0.02-0.23 nm(-2)). These materials are unique in maintaining a hydrophilic silica surface, as probed by H2O physisorption measurements, while possessing a high ...

The surface adsorption of heavy metals in effluents with nanoparticles is today asuitable method for effluents treatment. In the present study, lignocellulose nano-fibers(LCNFs) were used as natural adsorbent for lead adsorption. The aim was to evaluate leadadsorption using adsorption isotherms, kinetics and thermodynamics. Fourier TransformInfrared Sp...

New materials capable of storing hydrogen at high gravimetric and volumetric densities are required if hydrogen is to be widely employed as a clean alternative to hydrocarbon fuels in cars and other mobile applications. With exceptionally high surface areas and chemically-tunable structures, microporous metal–organic frameworks have recently emerged as some of the most promising candidate mater...

Hydrogen storage capacity of some Li(+)/F(-) doped neutral and charged aromatic/antiaromatic systems is studied at the B3LYP, M05-2X, MPW1K and MP2 levels of theory. Various conceptual density functional theory based global and local reactivity descriptors, nucleus independent chemical shift (NICS), NICS-rate, interaction energy per H(2) molecule, reaction enthalpy and reaction electrophilicity...

In the present study, ZnO nanoparticles (NPs) were synthesized in zerumbone solution by a green approach and appraised for their ability to absorb Pb(II) ions from aqueous solution. The formation of as-synthesized NPs was established by X-ray diffraction (XRD), Transmission Electron Microscopy (TEM), and UV-visible studies. The XRD and TEM analyses revealed high purity and wurtzite hexagonal st...

Bottom ash, a waste of thermal power plants, and deoiled soya, an agricultural waste material, were employed for successful removal and recovery of hazardous phenol red dye from wastewaters. The adsorption characteristics and operational parameters were determined by monitoring different parameters such as effect of pH, effect of concentration of the dye, amount of adsorbents, contact time, and...

Equilibrium, kinetics and thermodynamic studies on the removal of Acid Red 14 (AR14) anionic dye by biosorption onto dried waste biomass of Saccharomyces cerevisiae have been investigated. In batch experiments, the parameters studied included the effect of the dye concentration, temperature, contact time, adsorbent dosage, agitation speed, pH, and salt concentration. The pseudo-first-order and ...

Adsorption of aqueous thiocyanate ions from bulk solution to the liquid/vapor interface was measured as a function of temperature by resonant UV second harmonic generation spectroscopy. The resulting adsorption enthalpy and entropy changes of this prototypical chaotrope were both determined to be negative. This surprising result is supported by molecular simulations, which clarify the microscop...