Removal of Colloidal Particles by using Gelation Reaction of Sodium Alginate

提出了一种利用天然聚合物的凝胶化反应来分离难过滤胶体悬浮液中的固液的新技术。这项技术在处理高固体浓度的胶体泥水时尤其有效，这种水通常是某些施工过程中产生的副产品。胶体悬浮液与海藻酸钠溶液混合，并将该混合物添加到氯化钙溶液中，导致胶体颗粒被海藻酸钙凝胶包裹。凝胶悬浮液在重力作用下被排出，然后凝胶颗粒被机械地表达出来。以钠基膨润土为实验材料，对该工艺的基本问题进行了研究。将海藻酸盐-膨润土混合物滴加到钙溶液中。减小混合物的液滴尺寸会加快凝胶反应，因为钙离子向液滴中的扩散决定了凝胶反应的速度。减少海藻酸盐含量会加速凝胶的表达，因为海藻酸盐含量与表达速率成反比。羧甲基纤维素(CMC)作为膨润土泥浆水的稳定剂不影响凝胶反应，但凝胶的表现率随着CMC含量的增加而降低。这是由于CMC的保水能力所致。

A novel technique utilizing the gelation reaction of natural polymers has been proposed for the separation of solid from liquid in difficult-to-filter colloidal suspensions. This technique is especially effective in the treatment of colloidal muddy water of high solid concentration, which is often produced as a byproduct of certain construction processes. Colloidal suspensions are mixed with a sodium alginate solution, and this mixture is added to a calcium chloride solution, resulting in the entrapping of colloidal particles by the calcium alginate gel. Gel suspensions are then drained gravitationally, followed by mechanical expression of gel particles. Fundamental aspects of this process are investigated using sodium bentonite as an experimental material. The alginate-bentonite mixture is added dropwise to the calcium solution. Decreasing the droplet size of the mixture expedites gelation since the diffusion of calcium ions into droplets determines the rate of gelation reactions. Reducing the alginate content expedites expression of the gel since alginate content is inversely proportional to the rate of expression. Carboxy methyl cellulose (CMC) as a stabilizer of bentonite mud water does not affect the gelation reaction, while the expression rate of the gel decreases with the increase in CMC content in the gel. This is due to the water retention capacity of CMC.