This paper concerns the improvement method that can increase the separation performance of commercial RO/NF membranes having low separation performance by model calculations. We assumed three cases; (1) a lot of defects absolutely, (2) low ζ potential in the defects, (3) coexistence both rp = 1 nm and rp > 1 nm defects. We concluded that (1) this calculation estimated the required improvement ratios from each value of σ pre-treatment to certain values of σ post–treatment, so this procedure could be a guideline for improving treatment was, (2) the lower ζ potential in the defects was, the higher increasing effect of separation performance by improving treatment, (3) in the membranes that had low ratio of a normal section, the separation performance decreased although the improving treatment was applied because of the existence of defects impossible to improve.

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The amino acids are produced usually by the fermentation as mixtures, which may be regarded as cations or anions according to the pH of the solution. The electrodialysis with ion-exchange membranes seems to be a very useful method to separate a desired amino acid from mixed amino acids. However, there has been no such study on a quantitative basis. In this work, using a glycine (Gly) as a typical amino acid, we studied the variation of the flux (J) of Gly as a function of pH during the electrodialysis and found that the flux of Gly was maximum at pH ≒ 3. It was also found that the relationship between the electric current density (I) and the flux of the total cations (JGly+H) was represented by a straight line through the origin when the concentration of Gly and pH were kept constant. It was evident that JGly+H was constant as long as I and pH were kept constant, independently of the concentrations of Gly.

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In order to evaluate the fouling potential of feed water in the membrane separation processes, we proposed a modified Silt Density Index (MSDI) measured by using the membrane having a smaller pore size than 0.45 μm, of which pore size was commonly used. The modified SDI was calculated from the same equation to evaluate the standard SDI (SSDI) defined by ASTM. We derived the theoretical relationship between SDI (both of SSDI and MSDI) and the four kinds of plugging coefficient K for the models of complete blocking filtration, intermediate blocking filtration, standard blocking filtration and cake filtration, supposing that the filtration curve of filtration time vs. filtrate volume follows the specific filtration model, and the effectiveness of MSDI as a water quality index was examined through comparison with measured SDI using the membranes of 0.45 μm (SSDI) and 0.20 μm (MSDI). The following results were obtained; (1) In the range of small Kb (K of the complete blocking filtration model) ,the relationship between Kb and the calculated SDI was approximately represented by a single curve regardless of initial flux of membrane J0. As a result Ki (= Kb /J0, K of the intermediate blocking filtration model) which is used for the water quality index free from the liquid temperature could be estimated from the measured SDI if J0 was known. (2) The calculated SDI was influenced by an initial filtrate volume (for example, 500ml at SSDI measurement) except for the intermediate filtration model. However, it was shown that its effect was small within the practical range of K. (3) The difference between the measured SDI and the SDI calculated from K obtained from the actual filtration curve was small in the range of small value of K or testing time Tm, and gradually increased as these values became large due to the deviation of actual curve from the curve expected by the filtration model.

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Astaxanthin, which is a natural carotenoid, is well known as a strong singlet oxygen scavenger. Upon expectation of rapid decay on astaxanthin in the nano emulsion resulting from accelerated oxidation, an elaborated combination of stabilizers has been formulated in the nano emulsion. Further, by optimizing the surface adsorption layer of the emulsifiers, we have succeeded in effectively preventing the nano emulsion droplets from coalescing for extended period of time. “Anti–ageing Cosmetics” containing astaxanthin was successfully realized with use of this astaxanthin nano emulsion.

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