One-dimensional (1D) geochemical transport modeling is used to demonstrate the effects of speciation and sorption reactions on the ground-water transport of Np and Pu, two redox-sensitive elements. Earlier 1D simulations considered the kinetically limited dissolution of calcite and its effect on ion-exchange reactions (involving Sr, Ca, Na, Mg and K), and documented the spatial variation of a S...

A previous study involving lead(II) [Pb(II)] sorption onto ferrihydrite over a wide range of conditions highlighted the advantages of combining molecular- and macroscopic-scale investigations with surface complexation modeling to predict Pb(II) speciation and partitioning in aqueous systems. In this work, an extensive collection of new macroscopic and spectroscopic data was used to assess the a...

This work aims at the modeling of bio-sorption of cadmium(II) onto physically and chemically activated Cajanus cajan (Pigeon pea) husks. Experimental data obtained were fitted to a number of isotherm and kinetic models, and the results interpreted. The monolayer Cd(II) bio-sorption capacities of the husk were found to considerably increase by 2.82 times due to chemical activation, for bio-s...

A possible mechanism of small molecule transport in glassy polymer membranes containing configurational free volume (i.e., triptycene moieties) is proposed. To this aim, a family triptycene-containing polybenzoxazoles (TPBOs) exhibiting systematically varied molar amount units, ranging from 25% to 100%, was selected perform light gas (N 2 , CH 4 and CO ) fundamental sorption-transport study. Th...

Crystalline cellulose chemically modified through a reaction with sodium trimetaphosphate (STMP) in an acidic or basic condition yielded Cel-P4 and Cel-P10. These phosphated solids were characterized by elemental analysis, X-ray diffraction (XRD), infrared (IR) spectroscopy, scanning electron microscopy (SEM), nuclear magnetic resonance (NMR) at the solid state for phosphorus nucleus and disper...

The purpose of this work is to assess the effectiveness of two grass covers (buffer zone and grass-covered inter-row), to reduce pesticide leaching, and subsequently to preserve groundwater quality. Lower amounts of pesticides leached through grass-cover soil columns (2.7-24.3% of the initial amount) than the bare soil columns (8.0-55.1%), in correspondence with their sorption coefficients. Diu...

Mg-Al-CO3 Layered double hydroxide (LDH) was prepared by co-precipitation method at constant pH, and subsequently used to remove Evans Blue (EB) and Yellow thiazole (YT) dyes from aqueous solutions. The obtained material was characterized by powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), thermal analysis and BET. The kinetic and equilibrium aspects of sorption ...

Acid-base and metal-based potentiometric titration methods were used to analyze sorption mechanisms of lead by Rhizopus arrhizus fungal biomass. Biosorption was not considered globally but as the result of successive sorption reactions on various binding sites with different selectivities. Precipitation occurred rapidly when lead concentration increased. Lead was sorbed essentially by carboxyli...

A wide range of homogeneous elastomeric membranes has been prepared using dicumylperoxide as a general cross-linking agent. The membranes have been used for both equilibrium sorption measurements and steady-state pervaporation experiments to study solution-diffusion phenomena in the removal of volatile organic components from aqueous solutions. Pervaporation experiments have been performed unde...