TREATMENT OF OIL-BEARING WATER BY SOLID PARTICLES

本项目旨在开发一种通过添加固体颗粒来收集油滴的处理油传动水的新方法。油应以集料的形式与水中的颗粒一起去除。疏水颗粒很难与水混合，尽管它们更容易与油沾湿。因此。选择亲水性CaCO_3（粒径：10-20mum）和石英（粒径：5-10mum）颗粒进行水处理。此外，这两种物质都很容易获得，而且对环境无害。对这些颗粒与油滴的粘附行为进行了详细的研究，以获得充分的粘附条件信息。然后，研究了这些颗粒对分散油滴的去除作用。研究结果总结如下：1。石英颗粒与油滴的粘附：在pH3的水相中，亲水的石英颗粒粘附在煤油滴上，而煤油滴不与石英表面接触。在这种情况下，带负电的石英颗粒和带正电的煤油液滴在水层上凝结。另一方面，在pH为11.5的CaCl_2溶液中，石英颗粒粘附在碳氢化合物液滴和煤油液滴上，油滴与石英表面直接接触。在这种情况下，石英颗粒和油滴之间的水层应该通过特定的相互作用去除，这可能是由于CaOH^+在石英和油表面的特定吸附。CaCO_3颗粒与油滴的粘附行为：当与足够体积的油混合时，在无表面活性剂的溶液中，CaCO_3颗粒在CaCO_3水悬浮液的自然pH（9.7）及以上时，容易与油滴粘附并漂浮。在弱碱性溶液中，油滴与带极弱电荷的CaCO_3颗粒之间的势垒较低，可以解释其粘附性。而在高碱性pH下，溶解的Ca^<2+>产生的CaOH^+被认为增强了附着力。十二烷基苯磺酸钠是一种优先吸附油滴的表面活性剂，对颗粒-液滴的粘附有相反的作用。在(1)和(2)所述的条件下，发现有相当数量的煤油粘附在这些亲水性颗粒上。黏附密度随颗粒添加量的增加而降低。残油浓度与单位重量CaCO_3颗粒的油附着量呈正相关。通过逐步添加，将油浓度降低到5ppm（合法排水）所需的颗粒量大大减少。当油浓度较低时，颗粒的重复利用也能降低颗粒的总消耗量。所有使用的颗粒都因油的粘附而增强了混凝作用。含油污泥的含水率为30 ~ 40z，远低于常规絮凝法处理污泥的含水率（60 ~ 60Z）。少

The present project has been aimed at developing a novel method of treatment of oil-gearing water by addition of solid particles which would collect oil droplets. Oil should be removed together with the particles from the water, in the form of aggregate.Hydrophobic particles have difficulty in mixing with water, although they are more wettable with oil. Therefore. hydrophilic CaCO_3 ( size: 10-20mum) and quartz ( size: 5-10mum) particles have been chosen for the water treatment. In addition, both of them would be easily obtained and harmless to the environment. Adhesion behavior of these particles and oil droplets was studied in detail for sufficient information of proper condition for the adhesion. Then, removal of dispersed oil droplets by these particles was examined. The results are summarized as follows :1. Adhesion of quartz particles to oil droplets: In the aqueous phase of pH3, hydrophilic quartz particles adhered to kerosene droplets, whereas kerosene drops did not contact wit … More h quartz surfaces. It was suggested that, on this condition, the negatively charged quartz particles and the positively charged kerosene droplets coagulate across water layers. On the other hand, in CaCl_2 solution of pH 11.5, where quartz particles adhered to droplets of hydrocarbons as well as those of kerosene, oil drops were found to contact directly with quartz surfaces. In this case, water layers between quartz particles and oil droplets should be removed by specific interaction, probably due to specific adsorption of CaOH^+ on both quartz and oil surfaces.2. Adhesion behavior of CaCO_3 particles to oil droplets : When mixed with sufficient volume of oil, CaCO_3 particles in surfactant-free solutions easily adhered to and floated with oil droplets at and above the natural pH(9.7) of the CaCO_3 aqueous suspension. In weakly alkaline solution, the adhesion was explained in terms of low potential barrier getween an oil droplet and a very weakly charged CaCO_3 particles. While at high alkaline pH, CaOH^+ from dissolved Ca^<2+> was considered to enhance the adhesion. Sodium dodecyl benzenesulfonate, a surfactant which would adsorb preferentially onto oil droplets, was found to have reverse effect on particle-droplet adhesion.3. Considerable amount of kerosene oil was found to adhere to these hydrophilic particles under the conditions described in (1) and (2). Adhesion density was lowered with increasing addition of the particles. A correlation was implied between the residual oil concentration and the amount of oil adhesion to CaCO_3 particles of unit weight. The amount of the particles required to lower oil concentration to 5ppm ( legal for drainage ) was much decreased by stepwise addition. When oil concentration is relatively low, the total particle consumption was also able to ge lowered by reusing the particles. Coagulation was enhanced by oil adhesion for all particles used. Water content of the oil-bearing sludge was 30-40Z, which is much less than that of the sludge from a conventional flocculation method (>60Z). Less