Showing papers on "Sodium chlorate published in 1983"

Inhibition of chemoautotrophic nitrification by sodium chlorate and sodium chlorite: a reexamination.

Abstract: The oxidation of NH4+ by Nitrosomonas europaea was insensitive to 10 mM NaClO3 (sodium chlorate) but was strongly inhibited by NaClO2 (sodium chlorite; Ki, 2 μM). The oxidation of NO2− by Nitrobacter winogradskyi was inhibited by both ClO3− and ClO2− (Ki for ClO2−, 100 μM). N. winogradskyi reduced ClO3− to ClO2− under both aerobic and anaerobic conditions, and as much as 0.25 mM ClO2− was detected in the culture filtrate. In mixed N. europaea-N. winogradskyi cell suspensions, the oxidation of both NH4+ and NO2− was inhibited in the presence of 10 mM ClO3− after a 2-h lag period, despite the fact that, under these conditions, ClO2− was not detected in the filtrate. The data are consistent with the hypothesis that, in mixed culture, NH4+ oxidation is inhibited by ClO2− produced by reduction of ClO3− by the NO2− oxidizer. The use of ClO3− inhibition of NO2− oxidation in assays of nitrification by mixed populations necessitates cautious interpretation unless it can be shown that the oxidation of NH4+ is not affected.

Production of chlorine dioxide

Abstract: Chlorine dioxide is generated at high efficiency from feeds of chlorate cell liquor, sulphuric acid and methanol by a hybrid of reaction of sodium chlorate with sulphuric acid and methanol and reaction of sodium chlorate with sulphuric acid and sodium chloride. The reaction medium is maintained at its boiling point under a subatmospheric pressure while sodium sesquisulphate precipitates from the reaction medium.

Electrochemical chlorine dioxide process

Abstract: A continuous process for the production of chlorine dioxide by the electrolysis of an aqueous solution of sodium chlorite is provided. The process comprises electrolyzing the aqueous sodium chlorite solution to produce chlorine dioxide which dissolves to produce an aqueous solution of NaClO 2 containing chlorine dioxide. The aqueous solution of sodium chlorite-containing ClO 2 is passed through a photometric cell to measure the chlorite ion concentration as a function of the color produced by the ClO 2 -NaClO 2 -H 2 O system. Chlorine dioxide gas is removed from the aqueous solution and recovered. The novel process of the present invention employs solutions containing low, accurately controlled concentrations of sodium chlorite ion which when electrolyzed avoid the formation of by-products such as a dark colored chlorine dioxide complex and sodium chlorate.

High efficiency chlorine dioxide process

Abstract: Chlorine dioxide is formed at high efficiency from a solution of acid sodium chlorate at high sulphuric acid normality to which methanol is fed. The reaction medium is at its boiling point under a subatmospheric pressure. Total acid normality values in the range of about 7 to about 9 normal may be used while high efficiency of chlorine dioxide production is maintained.

Chlorine dioxide process

Abstract: Chlorine dioxide is formed at high efficiency from a solution of acid sodium chlorate at high sulphuric acid normality in excess of 9 normal to which methanol is fed. The reaction medium is at its boiling point under a subatmospheric pressure. The incidence of white-outs is avoided by feeding chloride ions to the reaction medium, while the efficiency of chlorine dioxide production remains high.

Polymers of unsaturated acids

Abstract: HYDROSOLUBLE POLYMERS FROM ACRYLIC ACID, OPTIONALLY WITH OTHER MONOMERS HAVE A DISTRIBUTION OF NARROW MOLECULAR MASSES AND ARE OBTAINED BY A CONTINUOUS LOOP POLYMERIZATION IN THE PRESENCE OF SODIUM SODIUM CHLORATE AND SODIUM AML CHLORATE. LOOP POLYMERIZATION GIVES A MORE UNIFORM PRODUCT THAN DISCONTINUOUS OPERATION AND THE NARROW DISTRIBUTION OF MOLECULAR MASSES PROVIDES POLYACRYLATES USEFUL FOR THE TREATMENT OF WATER, INHIBITION OF TARTAR AND AS DISPERSANTS.

Improved method to measure erythrocyte filtration times increased extremely by chlorate.

Abstract: A method is presented that allows the measurement of erythrocyte filtration times that are extremely prolonged. Filtration times through polycarbonate sieves are increased by a factor of 40 after 2 h incubation with 30 mM sodium chlorate. This increase in red cell rigidity offers an explanation for the haemolysis observed in chlorate poisoning in vivo.

Convection effects during the crystal growth of sodium chlorate from aqueous solutions

Abstract: I n the near vicinity of a crystal growing from a multicomponent isothermal system, there is a density gradient; thus, convection currents occur around the crystal. We have studied the crystal growth of NaCIO, from aqueous supersaturated solutions in which the crystal fills the bottom of a rectangular cell (FIGURE I). The concentration gradients were observed by the Schlieren technique; the fluid movements were measured at the same time by the observation of aluminum flakes. For a crystal growth rate of about lo-’ cm S S ’ , there is only one convection roll in the cell, which has a velocity of about 10 * cm s ’ . In this regularly moving fluid, the concentration gradient has a turbulent movement: There are “blobs” of lighter solution ascending periodically from the crystal (the period is about 1 to 10 seconds, according to the supersaturation of the solution).’.* A slight inclination of the cell from the vertical changes this flow regime into another one, with the roll axis perpendicular to the previous one. For an inclination of 90% (the normal to the growing face being horizontal), there is no more convection-the lighter part of the solution only accumulates a t the top of the cell. We have superimposed a thermal gradient to the concentration gradient due to the growth: The convection rate can be enhanced or reduced, according to the relative orientations of these gradients. Consequently, the growth rate of the crystal is accelerated or reduced. We also studied the dissolution of a crystal a t the bottom of a cell heated from below. At the beginning of the dissolution, the stabilizing concentration gradient is so high that there is no convection just above the crystal, but only in the upper part of the cell. In the lower, immobile part of the solution, the heat is transmitted by diffusion and high temperature gradients exist (about loo C cm-I). On the other hand, the temperature is nearly constant in the entire convective part of the cell (FIGURE 2a). The immobile part of the solution expands as the dissolution and mass diffusion proceed; the whole fluid becomes immobile, with a smooth temperature distribution. After about ten hours, convection takes place at the bottom of the cell, the higher part of the fluid being motionless (FIGURE 2b). I n the vicinity of the transition, the temperature a t a given point of the cell oscillates with an amplitude of about 1 O C and a period of about 2 s’. Sodium chlorate has a polar crystal structure, the morphology being mainly cuboid. We have found that the apparition of the tetrahedron is not so much a question of supersaturation; rather, it is controlled mainly by the direction in which solution circulates around the crystal. We suspended a cubic crystal with the 11 1 axis vertical in an evaporating solution. Whatever the growth rate, three tetrahedron faces appear at the upper corners only if [I I I ] is pointing downwards (FIGURE 3a). I f such a crystal