The effect of salt on phages and their host bacteria was investigated using phage J1 of Lactobacillus casei S1 and phages M2 and SPO1 of Bacillus subtilis YS11. With phage J1 at 37°C, salt did not affect the infectivity of the phage, but prevented its adsorption. Salt completely inhibited the growth of phage at 1.0 M. With phages M2 and SPO1, salt did not affect the infectivity of phages. It prevented the adsorption of phage SPO1, but not of phage M2. Salt completely inhibited the growth of phages at 1.2-1.3 M. At 40°C in the absence of salt, the growth of phage J1 was completely inhibited, whereas the growth of the host bacteria was the same as at 37°C. With phages M2 and SPO1 at 45-46°C, growth was completely inhibited, whereas the growth of the host bacteria was more rapid than at 37°C. These findings suggest the possibility of phage control by means of elevating incubation temperature. At 39°C, lower concentrations of salt inhibited the growth of phage J1. This result suggests the possible use of salt for the control of phage. With phages M2 and SPO1, this is not true at 44-45°C.
Four measurement methods of membrane conductivity of an ion-exchange membrane, such as the constant-distance method, variable-distance method, multi-membrane method and a potential-step method, were compared by using smooth platinum (Pt) plates or platinized Pt plates as measuring electrodes. The conductivities of a Neosepta C66-5T membrane equilibrated with 0.05-5kmol·-3 NaCl solution was measured at 298 K. An equivalent circuit model, composed of an overall resistance including electrolyte and membrane resistances, electrode-reaction resistances and electrode capacitance, was used for calculation of membrane resistance. Capacitance on a smooth platinum plate ranged between 15-60μF, but that on a platinized platinum ranged between 500-2500μF, which were a function of electrolyte concentration and electrode distance. The conductivities calculated from the resistances measured by different methods had similar tendencies, increasing with the increasing concentration of external NaCl solution, but showed scattered values. Since the measured resistance was sensitively affected by small capacitance, the conductivity estimated by the constant-distance method using smooth Pt plates showed the highest value. When using Pt-plated Pt plates, the calculation of conductivity was less affected by the capacitance. The membrane conductivity was calculated by subtraction of the solution resistance from the overall resistance including solution and electrolyte resistances. When the membrane resistivity is close to the solution electrolyte, the subtraction value becomes negligibly small, and therefore the calculation error becomes larger. A DC electrolysis method using a potential step is tested as an alternative method to a AC resistance method. Then a potential-step method using a Pt-plated Pt plates was found to be useful for measuring wide ranging conductivities of an ion-exchange membrane.
Five kinds of manganese-oxide adsorbent granulated with different particle sizes were prepared using polyvinyl chloride (PVC) as a binder. Rates of lithium adsorption on the adsorbents were measured in lithium-enriched seawater ([Li]=3.1mg·dm-3) by a batch method. The intraparticle diffusivities (Dp's) of lithium were evaluated in terms of the model of pore diffusion with a Freundrich-type adsorption isotherm. The Dp values were about 2×10-6 cm·s-1 and slightly dependent on particle size. The Dp values were also evaluated using column adsorption data. The calculated values(about 4×10-6cm·s-1)agreed comparatively well with those derived from the batch adsorption data. The agreement suggests that the intraparticle diffusion is a rate-determining step in column adsorption at space velocity above 200 h-1.
Trace amounts of iron and copper in sea water and common salt were determined by atomic absorption spectrophotometry in conjunction with the solvent extraction technique. Both metals reacted with 2-hydroxy-1-naphthaldehyde-4-phenyl-3-thiosemicarbazone (HNA·PS) to form complexes, which were extracted into chloroform. The optimum conditions for the simultaneous extraction of iron and copper were examined. Both complexes were decomposed with a nitric acid-perchloric acid mixture, and then dissolved with 0.1M hydrochloric acid. The resulting solutions were sprayed into an acetylene-air flame. Less than 10μg of iron and copper was quantitatively extracted into 10ml of 1.5×10-3M HNA·PS chloroform solution from the aqueous solution at pH 5 by shaking for 10min. The same samples of sea water, common salt, and imported salt were analyzed.