Monazite-cheralite ceramics are a promising waste form for actinides. To elucidate the long-term behavior of this matrix in aqueous solutions, study measured thermodynamic data Th-rhabdophanes Ln1-2xCaxThxPO4·nH2O (with Ln = Pr, Nd; x 0–0.15) and associated anhydrous monazite-cheralites Ln1-2xCaxThxPO4. Solubility experiments at 298 K high temperature oxide melt solution calorimetry were combin...

Mg-Al layered double hydroxides (LDHs) were applied to soils for controlling phosphorus (P) loss. The subsequent slow-release of immobilized P in LDHs-soil system is crucial its bioavailability crops. Saturated column experiments conducted investigate the influence carbonate and flow interruption (FI) on release retention phosphate results compared those obtained under bicarbonate or continuous...

r a 200 .027 sent add gmail.c Summary Inverse geochemical modeling (PHREEQC) was used to identify the evolution of groundwater with emphasis on arsenic (As) release under reducing conditions in the shallow (25–30 m) Mississippi River Valley Alluvial aquifer, Arkansas, USA. The modeling was based on flow paths defined by high-precision (±2 cm) water level contour map; X-ray diffraction (XRD), sc...

The cyclic injection of oxygenated water in an aquifer may induce in situ iron removal from groundwater. During injection of aerated water, sorbed ferrous iron is displaced by cations, oxidized in the pore space, and precipitated as ferric iron oxyhydroxide. During pumping, ferrous iron is sorbed from groundwater on the exchange and sorption sites, and the breakthrough of dissolved iron is reta...

Available surface complexation models for birnessite required the inclusion of bidentate bonds or the adsorption of cation-hydroxy complexes to account for experimentally observed H/M exchange. These models contain inconsistencies and therefore the surface complexation on birnessite was re-examined. Structural data on birnessite indicate that sorption sites are located on three oxygens around a...

In situ chemical oxidation (ISCO) has been widely used in recent years for the remediation of VOC contaminated soil and groundwater. Among several chemical oxidizing agents injected into the subsurface for ISCO, persulfate has often been selected due to the advantage of being less reactive and longer-lived in the subsurface environment. Through this research, the effect of side reactions occurr...

An innovative approach using solid/liquid interface characterization (zetametry measurements, ATR-IR), coupled with ex situ FTIR has been used to build a phosphate complexation model at the alumina surface via PHREEQC software. According phosphorus coverage impregnated on surface, two mechanisms of adsorption have identified: specific complex adsorbed predominant facet and precipitation process...

Polypyrrole (PPy) was chemically synthesised at two pH levels (pH = 2 and unadjusted pH, i.e. 6.6) using pre-formed carboxymethylcelluloseiron (CMC-Fe) complexes. The CMC-Fe complexes were prepared at a fixed CMC concentration, i.e. 5.5x10 mol/L, and with an increasing FeCl3 amount (from 4x10 to 5x10 mol/L). The quantity of iron bound to CMC was determined by the inductively coupled plasma (ICP...