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收集油滴来处理含油废水的新方法。油应该以聚集体的形式与颗粒一起从水中去除。疏水颗粒很难与水混合，尽管它们更容易与油混合。因此。选用亲水性CaCO_3（粒径10- 20 μ m）和石英（粒径5- 10 μ m）作为水处理剂。而且，这两种物质都很容易获得，对环境无害。详细研究了这些颗粒和油滴的粘附行为，为粘附的适当条件提供了足够的信息。然后，检查这些颗粒对分散的油滴的去除。主要研究结果如下：1.石英颗粒与油滴的粘附：在pH = 3的水相中，亲水性石英颗粒粘附在煤油滴上，而煤油滴不与石英颗粒接触。 ...更多信息 h石英表面。有人建议，在这种条件下，带负电荷的石英颗粒和带正电荷的煤油液滴凝聚跨越水层。而在pH 11.5的CaCl_2溶液中，石英颗粒附着在烃和煤油液滴上，油滴则直接与石英表面接触。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被去除，这可能是由于CaOH^+在石英和油表面的特定吸附。CaCO_3颗粒对油滴的粘附行为：当CaCO_3水悬浮液的自然pH值（9.7）及以上时，无表面活性剂的CaCO_3颗粒与油滴混合时，易于粘附并与油滴一起漂浮。在弱碱性溶液中，油滴与带极弱电荷的CaCO_3颗粒之间的低势垒解释了这种粘附。而在高碱性pH下，溶解的Ca^<2+>中的CaOH^+被认为增强了粘附。表面活性剂十二烷基苯磺酸钠优先吸附在油滴表面，对油滴粘附有相反的影响.在（1）和（2）中所述的条件下，发现相当大量的煤油粘附在这些亲水性颗粒上。粘附密度随着颗粒添加量的增加而降低。残油浓度与单位质量碳酸钙颗粒上的残油附着量之间存在相关性。通过逐步添加，将油浓度降低到5 ppm（对于排水来说法律的）所需的颗粒的量大大降低。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。对于所使用的所有颗粒，通过油粘附来增强凝结。含油污泥的含水率为30- 40 Z，远低于常规絮凝法所得污泥的含水率（> 60 Z）。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