シリカコーティングした廃石こうボードの水質浄化特性

抄録

We previously reported that water purification materials with high phosphorus removal capacity made from PVB-coated gypsum board. In this study, we tried to prepare the material removes phosphorus and organic substances with silica-coated gypsum boards. Test pieces cut out from commercial gypsum board was coated by immersing in silica sol and drying in the air at 50°C. Microorganisms were supported on the silica-coated samples by immersing in a culture solution containing lactobacillus, bacillus natto and saccharomyces. For gypsum board silica coated two or three times the surface did not collapse after long-term removal phosphorus. From the results of SEM observation, precipitation of calcium carbonate and adhesion of microorganisms were confirmed on the surface of the silica-coated samples. The silica-coated sample immersing in a culture solution was able to remove organic substances. However, the phosphorus removal performance decreased. In the sample immersed in a culture solution, although calcium ion dissolved enough, the amount of calcium carbonate decreased. From this result, it was found that the amount of calcium carbonate greatly contributes to the phosphorus removing ability in this study. Therefore, high phosphorus removal performance was obtained by the sample carbonated by 0.5 mol/L sodium carbonate aqueous solution. In addition, the phosphorus removal ratio in the sample immersed in a culture solution was lower on 5 days than on 3 days. This result is because calcium phosphate was dissolved in lactic acid produced by lactobacillus.