Study the transport properties of anion and cation exchange membranes toward various ions using chronopotentiometry
The transport properties of various anion and cation exchange membranes were studied in different electrolyte solutions using chronopotentiometry technique to get insight about the influence of the counter ion on the transport properties of the membranes. The investigated samples include heterogeneous ion exchange membranes varying in the functionality of fixed charged groups, physical properties of the polymer and the preparation procedure. Chloride and nitrate were investigated as counter-ion in their sodium salts for anion exchange membranes while sodium, calcium, potassium, and magnesium were selected as counter-ion in their chloride salts to study cation exchange membranes transport properties. First, the current – voltage curve of an ion exchange membrane in a given solution was recorded to obtain the limiting current, then a constant current above the limiting current was used for chronopotentiometry measurement. In all the studied membranes the potential across the membrane remained constant for a time interval called the transition time , when a constant current was applied. Then the potential increased rapidly to reach the steady state potential. The permselectivty and the transport number of a membrane were calculated using the corresponding transition time.
Electrocatalytic Oxidation Study of Theophylline on a Copper Nanoparticles-Modified, Carbon Paste Electrode Based on Cyclic Voltammetry
In this study, the Cu nanoparticles were prepared by reducing CuSO4. These particles were used in making copper nanoparticles modified carbon paste electrode (nano-CPE). The electrochemical characteristics of this electrode (nano-CPE) were investigated. The results of the electrocatalytic oxidation of theophylline (TP) on nano-CPE, using cyclic voltammetry technique showed that nano-CPE, has more reactivity and more effective surface area, as compared to the unmodified carbon paste electrode (un-CPE). The investigation of voltammograms obtained from oxidation of TP at different scan rates on the nano-CPE confirmed a cyclic mediated redox mechanism followed by reducing Cu(III) which is a chemical reaction (EC mechanism). These species formed in more positive potentials and act as a redox intermediate for TP oxidation. There was a linear relationship between the oxidation peak current and the square root of scan rate, showing that the oxidation reaction of TP at nano-CPE might be due to the diffusion-controlled process.
Proliferative kidney disease: first reported outbreak in North America
Abstract. Proliferative kidney disease (PKD) was diagnosed in rainbow trout, Salmo gairdneri Richardson, at the Hagerman, Idaho, State Fish Hatchery. Wild fish from Riley Creek, one of the hatchery water supplies, were infected with PKD organisms. Clinical signs, gross pathology and histopathology of affected fish were typical of those reported for PKD in salmonids from European hatcheries. In addition to lesions normally seen, we observed a severe vasculitis and occlusion of renal and hepatic vessels. Ultrastructure of the PKD organism and possible inclusion body production sites are described. The disease outbreak was complicated by the presence of other infectious diseases. This is the first recorded outbreak of PKD in North America.