Volume 2, Issue 1, 2008

Structural Changes Associated with Interactions Between Starch and Particles of TiO2 or ZnSe
Paul Bernazzani, Hari Krishna Reddy Pandi, Vamshi Krishna Peyyavula

Abstract
The effects of modifying the structure of the starch chain on the kinetics of enzymatic cleavage are presented. The structural modifications involved interactions between the biopolymer chains and two types of transition metal particles: ZnSe, and TiO2. The structural changes were followed using Raman spectroscopy and differential scanning calorimetry (DSC) while the enzymatic activity was determined using the starch-iodine complexation method. Results show that interactions with ZnSe increase the rate of digestion while interactions with TiO2 significantly slow down the reaction. Structural analysis suggests that strain variations in the backbone are the driving forces behind the experimental observations. Full Article

Predictive Simulation for Separation of Toxic Metal Ions by Ion-Exchange Resins in Complex Media   Madjid Hadioui, Mohamed Oimar Mecherri, Zahia Harrache

Abstract
A calculation program based upon predictions was developed to foresee the separation conditions by ion exchange for two divalent metal ions often encountered together. The simulations were compared to experimental results obtained in similar conditions in complex media. Whilst the separation by batch method was found unlikely for these metals on Dowex-50-X8 resin in these conditions, our program shows that quantitative separation of these species in column is achieved by sequential elutions with chelating agent solution and the correlation with experimental verification applicable. The simulations described could be a didactic illustration for selective separation using these types of resins. Full Article