1997 Volume 59 Issue 1 Pages 59-68
In the hydroponic culture, pH variance is a very important problem. In general, acid and alkali are used in correcting nutrient pH. In this study, the use of minerals, which causes pH-buffer by negative charge, was discussed in order to get the discernment for developing a pH-buffer water treatment system. A prototype water circulation system using “Bakuhan-seki” was produced, and pH-buffer test was carried out using distilled water. As the results, water and nutrient water treated by the system showed pH-buffer action, and the treated water turned to turbid water by the peeled off corpuscle of “Bakuhan-seki”, and the turbidity of the treated water tend to swell in proportion to the increase of the volume of granular “Bakuhan-seki” and of the treatment time. As the results of the measurement of zeta potential, the values of zeta potential (mV) were -10.2, -31.5 and -39.7 when 2.5, 6.9 and 12.0 respectively. Additional negative charge of “Bakuhan-seki” changed in proportion to the pH value of surrounding solution.
