2021 年 9 巻 8 号 p. 398-402
Untreated oil-contaminated water discharge from domestic and industrial sources has led to serious environmental pollution, especially in developing countries. Many technologies (e.g., floatation and coagulation, biological treatment, membrane separation, and so on) have been developed to treat effluents. Among them, the oil-water separation utilizing hydrophobized filtration beds can be expected to be a cost-effective and quick treatment technology. Previously, hydrophobized solid grains have been preliminary tested but applicability of hydrophobized porous grains have not been fully examined in oil-water separation system. This study aimed to characterize the hydrophobicity for artificially hydrophobized porous grains of autoclave aerated concrete (AAC) grains. The AAC grains (0.106 to 0.250 mm) were coated with two hydrophobic agent (HA) such as oleic acid (OA) and stearic acid (SA) at different concentrations (5 to 750 g of HA / kg of AAC grains). The OA-coated grains exhibited high hydrophobicity with HA > 50 g/kg while for SA-coated grains, hydrophobicity became significant from HA > 5 g/kg. Both OA- and SA-coated grains gave a rapid increase with increasing HA concentration and maximum contact angles reached 140–145o, suggesting that they had a high potential to apply in the filtration beds in oil-water separation system.
