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实现难过滤胶体悬浮液的固液分离的新技术。将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。胶体颗粒被固定在凝胶中。凝胶悬浮液在重力作用下被潮解，然后凝胶颗粒被机械地表达。在表达过程中，胶体颗粒留在凝胶中，所表达的液体是透明的。表达出来的蛋糕最终被丢弃。这项技术的基本方面是通过使用两种胶体材料进行研究的：汽车蜡和环己烷乳液。该技术有效地去除了乳化液中的车蜡和环己烷。为推广该技术去除溶解有机物，将上述工艺与吸附工艺相结合。甲苯胺蓝(TB)被用作溶解有机物。它被胶体二氧化硅颗粒吸附。吸附剂(胶体二氧化硅颗粒)对海藻酸凝胶中的溶解物质起着重要的滞留作用。利用颗粒固定化技术也可以实现非水胶体分散体系中胶体颗粒的去除。利用12-羟基硬脂酸在植物油中的凝胶化反应对该工艺进行了研究。将直径为0.15μm的聚甲基丙烯酸甲酯与12-羟基硬脂酸混合。包埋在PMMA颗粒中的有机凝胶被潮解。结果表明，当原始油粒混合物中PMMA浓度大于1000ppm时，约有10%的PMMA粒子从凝胶中逸出。结果表明，混合物中PMMA浓度越高，挤压液中PMMA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.