Biosorption of chromium (Cr) onto algae (Ulva.lactuca): application of isotherm and kinetic models

The biosorption of chromium (VI) ions to Ulva.lactuca studied in a batch system with respect to the concentration, initial pH and initial metal ion concentration. The algal biomass exhibited the highest chromium (VI) adsorption capacity at 20°C, at the initial pH value of 3.0. Biosorption capacity increased from 0.70 to 1.08 mg g-1 with an increase in initial chromium (VI) concentration from 29.14; 38.28; 58.47 mgL-1. Freundlich and Langmuir isotherm models were tried to represent the equilibrium data of chromium (VI) biosorption depending on concentration. Equilibrium data fitted very well to the Langmuir model in the studied concentration range of chromium (VI) ions at all the concentrations studied. The pseudo second-order kinetic model was also applied to experimental data assuming that the external mass transfer limitations in the system can be neglected and biosorption is sorption controlled

Impact and Epidemiological Investigations into the Incursion and Spread of Peste des Petits Ruminants in the Comoros Archipelago: An Increased Threat to Surrounding Islands

International audienceLate October 2012, a great number of deaths of unknown origin occurred in goat herds in the suburbs of Ngazidja, located in the Comoros archipelago. Few weeks later, laboratory testing requested by the animal health authorities resulted in the identification of peste des petits ruminants (PPR) infection. Notably, the Index case could be attributed to a sick goat imported from Tanzania. Viral isolation was successful from the lungs leading to the whole N nucleoprotein gene sequencing. Phylogenetic analysis revealed that the strain belongs to the lineage III which includes strains of eastern African origin. In addition, to evaluate the impact of PPR on the Comorian indigenous domesticated ruminant population, a cross-sectional PPR serological survey was conducted between April and July 2013. A low overall PPRV antibody prevalence 2.24% (95% CI [1.38; 3.08]) was detected with a Grande Comore prevalence of 3.34% (IC = [2.09; 4.63]) with a limited spread of the disease mainly due to farm practices such as limited contacts between farm animals and rapid slaughtering of sick animals