Interest of a chemometric approach in understanding the retention behaviour of three columns in hydrophilic interaction liquid chromatography: application to the separation of glycerol carbonate, glycerol and urea.

A chemometric approach was used to study the retention behaviour of glycerol, urea and glycerol carbonate in hydrophilic interaction liquid chromatography (HILIC). First, a simplex method was developed to optimize the sensitivity of an evaporative light scattering detector. A mixture design was then applied to model retention factors as a function of the mobile phase content in acetonitrile, water and methanol on three columns: Atlantis HILIC Silica, ZIC-HILIC and Monochrom diol.

Modelling of influential parameters on a continuous evaporation process by Doehlert shells.

The modelling of the parameters that influence the continuous evaporation of an alcoholic extract was considered using Doehlert matrices. The work was performed with a wiped falling film evaporator that allowed us to study the influence of the pressure, temperature, feed flow and dry matter of the feed solution on the dry matter contents of the resulting concentrate, and the productivity of the process. The Doehlert shells were used to model the influential parameters.

Kinetic modelling of the degradation of the alpha-tocopherol in biodiesel-rape methyl ester.

The aim of this work was to study the influence of three major factors (light, atmospheric oxygen, temperature) responsible for the degradation of tocopherols. The evolution of alpha-tocopherol contents was analysed by high-performance liquid chromatography. Taguchi's experimental design was applied to establish a mathematical model of alpha-tocopherols degradation in function of the studied parameters especially in a domain of temperature between 50 degrees C and 150 degrees C.

Purification of sugar beet vinasse - adsorption of polyphenolic and dark colored compounds on different commercial activated carbons.

The adsorption on activated carbons of dark colored compounds contained in sugar beet vinasse was studied. Four commercial activated carbons with different properties (particle size, residual acidity and microporous properties) were respectively checked for efficiency at two temperature levels (25 degrees C and 40 degrees C) and at four pH levels (2,3.5,7,10).

Removal of lead (II) ions from synthetic and real effluents using immobilized Pinus sylvestris sawdust: adsorption on a fixed-bed column.

The purpose of this work was to evaluate the potential of Pinus sylvestris sawdust, in a continuous flow removal of lead (II) ions from synthetic and industrial aqueous effluents. The kinetic parameters obtained in a batch process were used to scale-up the process on a mini-column and to choose the breakthrough model. The column experimental data concerning the volumes treated were correlated using the bed depth service time model.

Removal of Cd(II) and Pb(II) ions, from aqueous solutions, by adsorption onto sawdust of Pinus sylvestris.

Fixation of heavy metal ions (Cd(II) and Pb(II)) onto sawdust of Pinus sylvestris is presented in this paper. Batch experiments were conducted to study the main parameters such as adsorbent concentration, initial adsorbate concentration, contact time, kinetic, pH solution, and stirring velocity on the sorption of Cd(II) and Pb(II) by sawdust of P. sylvestris.