Flocculation Properties Of Vegetable Tannin

In the industrial wastewater and sewage treatment in the study, flocculation precipitation because treatment can be effective in reducing the turbidity and color, can remove a variety of organic polymers and certain metal ions to improve sludge dewatering performance are widely used. In recent years, the flocculants develop from traditional inorganic to inorganic polymer flocculants, and microbial organic polymer flocculant. Natural polymer flocculant for the research and development of active promotion of the green industry, water treatment system using "green flocculant" is especially important practical significance.The use of supercritical CO2 extraction from the natural polymer material tannin as flocculants, flocculation performance and study its flocculation effect. In water treatment, tannin with flocculation, deoxy, corrosion and scale inhibitors and bactericidal effect, is a multi-functional water treatment agent. Tannin as a flocculant is the most important role, combination and precipitation with proteins, polysaccharides, polyvinyl alcohol, non-ionic surfactant, and the precipitation of metal ions to achieve the effect of water purification.Through laboratory tests, study different species in the genus raw materials tannin content size, as well as their flocculation effect, through further screening, to elect suitable and better flocculation effect of plant materials, performance study. Using advanced supercritical CO2 extraction technology, research in the extraction of tannin in the optimization process, in order to fully use this technology to raise the yield of tannin, to improve the flocculation rate. Flocculant flocculation performance by many factors, in order to better improve the flocculation of tannin, under appropriate conditions, the extraction of tannin research coagulation factors and analysis of flocculation process of the various controlling factors affecting , and ultimately to enhance flocculation performance. In order to investigate the plant tannin in the actual water flocculation effect, choosing life and industrial wastewater do small test, in the practical application of wastewater to provide theoretical and data support.The results showed that plant resources in the region, selected the willow containing more tannin, flocculation effect is more obvious. Under Supercritical CO2 extraction in the best conditions, the extraction pressure of 20 MPa, the extraction temperature of 60℃, the extraction time of 90 min, the volume ratio of 70 % cosolvent ethanol (the amount per gram 4 mL), the tannin extraction of flocculation process study through various influencing factors, founding under the concentration of 20 mL/L, 60 mL dosage, precipitation time 5 min, pH 3.0, the temperature 25℃test conditions, Kaolin processing suspension flocculation, coagulation rate is about 95 percent. In addition, the tannin flocculation of the actual wastewater treatment plays a certain role.Test shows that vegetable tannins as a natural polymer flocculant is safe, innocuity, simple operation, and kaolin suspension flocculation treatment has a good effect , and flocculation process to purify wastewater also has functions.