A new process for the removal of colloidal particles from waste liquid by use of particle immobilization in gel

提出了一种利用凝胶中颗粒固定化的新技术，用于难以过滤的胶体悬浮液的固液分离。将海藻酸盐水溶液和胶体悬浮液的混合物滴加到氯化钙水溶液中，得到海藻酸钙凝胶。胶体颗粒固定在凝胶中。凝胶悬浮液在重力作用下析出，然后进行凝胶颗粒的力学表达。在表达过程中，胶体颗粒保留在凝胶中，表达液清澈。最后将表达好的蛋糕丢弃。该技术的基本方面进行了研究，使用两种胶体材料：汽车蜡和环己烷乳液。该技术可有效去除乳液中的车蜡和环己烷。将上述工艺与吸附工艺相结合，以扩展该技术对溶解性有机物的去除。甲苯胺蓝（TB）被用作溶解的有机物。它被胶体二氧化硅颗粒吸附。在海藻酸盐凝胶中，吸附剂（胶体二氧化硅颗粒）对保留溶解物质起着重要作用。从非水胶体分散体系中去除胶体颗粒也可以通过使用颗粒固定化技术来实现。研究了12-羟基硬脂酸在植物油中凝胶化的方法。将直径为0.15 μm的聚甲基丙烯酸甲酯（PMMA）颗粒油与12-羟基硬脂酸混合。将包裹PMMA颗粒的有机凝胶分离。结果表明，当原始油-颗粒混合物中PMMA的浓度大于1000ppm时，约有10%的PMMA颗粒从凝胶中逸出。结果表明，混合料中PMMA的浓度越高，挤压液中PMMA的浓度越低。

A new technique utilizing particle immobilization in gels has been proposed for a solid-liquid separation of difficult-to-filter colloidal suspensions. A mixture of alginate aqueous solution and colloidal suspension is added dropwise to a calcium chloride aqueous solution, resulting in calcium alginate gels. Colloidal particles are immobilized in the gels. The gel suspension is deliquored gravitationally, followed by mechanical expression of the gel particles. During the expression, the colloidal particles remain in the gels and the expressed liquid is clear. The expressed cake is finally discarded. Fundamental aspects of this technique are investigated by use of two kinds of colloidal materials : car wax and cyclohexane emulsions. The car wax and cyclohexane in the emulsion are effectively removed by this technique. To extend this technique for removal of dissolved organic matter, the above process is combined with adsorption process. Toluidine blue (TB) is used as dissolved organic matter. It is adsorbed by colloidal silica particles. The adsorbents (colloidal silica particles) play an important role to retain dissolved matter in alginate gel. Removal of colloidal particles from non-aqueous colloidal dispersion system can also be attained by use of the particle immobilization technique. This technique is investigated by use of gelation of 12-hydroxy stearic acid in vegetable oil. The oil containing polymethyl metacrylate (PMMA) particles of 0.15 μm in diameter is mixed with 12-hydroxyl stearic acid. The organogel entrapping PMMA particles are deliquored. It is shown that ca. 10 % of PMMA particles escaped from the gel, when the PMMA concentration in original oil-particle mixture is more than 1,000 ppm. It is found that the higher the concentration of PMMA in the mixture, the lower the concentration of PMMA in squeezed liquid.