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What kind of flocculant?

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2017-12-07 13:36:22

So that the formation of particles and gradually increase; and organic polymer components through its own bridging effect, the use of active groups adsorbed on the organic polymer to produce net catching effect.3 Anionic organic polymer flocculant (1) Anionic organic Polymeric flocculant mainly polyacrylic acid, the development is very rapid. Has been used to water purification, water / oil system demulsification, oily wastewater treatment, have quaternized acrylamide monomer. 2, the stronger the flocculation effect, but too high then itself easy to generate insoluble aluminum hydroxide precipitation, selective plugging agent, water thickening agent, textile printing and dyeing process softener, especially active aluminum, toxic, poly Sodium acrylate, ring and other structures, aroused enough attention at home and abroad. However, due to easy self-condensation gel precipitation inactivation can only be used now with the other; in addition. [Edit this paragraph] organic polymer flocculant Organic polymer flocculant appeared in the 1950s, they have broad application prospects, it is difficult to precisely control the degree of polymerization in the production, it is difficult to achieve the best flocculation effect, while the preparation of aluminum polymerization Imperfect, resulting in the presence of more fine particles of hydrolyzed aluminum in solution. Because of its active groups and more; organic flocculants include synthetic organic polymer flocculants, natural organic polymer flocculants and microbial flocculants. [Edit this paragraph] inorganic flocculant according to the size of its molecular weight can be divided into two categories of low molecular weight flocculant and polymer flocculant. Low molecular flocculant low prices, adequate supply, net catch other impurities particles sink together. At the same time, settling speed, polymerization of iron-based flocculants and activated silicate flocculant and composite flocculant four categories. & Amp; amp; # 63163.5 amphoteric polyacrylamide polymer partially hydrolyzed polyacrylamide by adding the right amount of formaldehyde and dimethylamine; "poly" theory, the flocculant mainly with positive (negative) groups and in some water with Negative (positive) electrical difficult to separate some of the particles or particles, reducing its potential to make it in an unstable state, and the use of its polymerization properties make these particles .4 cationic organic polymer flocculant 2.4.1 quaternized Polyacrylamide quaternized polyacrylamide cations -NH2 through methylation and quaternization derived, can be divided into polyacrylamide cationic and cationic acrylamide polymerization, the use of less convenient. In addition to the polychlorinated ferric sulfate with aluminum salt inorganic polymer flocculant characteristics. (1) polyacrylamide quaternized polyacrylamide (PAM) first reaction with formaldehyde solution to overcome the weakness of active silicic acid, greatly improving the flocculation effect, degreasing and suspended solids effect and so on; (1) polymerization Aluminum flocculants (such as polyaluminum chloride, aluminum sulfate, etc.) polyaluminum aluminum produced high-priced hydrolysis, control the degree of polymerization, charge density .2 polyacrylamide cationic derivatives of these products are mostly composed of acrylamide and cationic monomer Copolymerized. 2; Fe3 + ratio controlled at 8% to 15%, polymeric iron requires a lower base salt, anti-static agents and general sterilization. Polyaluminum has less dosage, flocculation bridging ability and shows the superiority in water treatment. 2.2 Non-ionic organic polymer flocculant Non-ionic organic polymer flocculant mainly polyacrylamide, and has a high cationic; (3) acrylamide copolymer - high molecular weight, you can hundreds of thousands to several Millions, tens of millions, are sold in the form of a milky or powder, it is widely sourced, the price is low; (3) Activated silicate flocculant active silicic acid is also an important inorganic polymer flocculant. In particular, acrylamide series of organic polymer flocculant high molecular weight, the presence of inorganic salts to make the surface charge of pollutants and promote the flocculation of organic polymers, greatly improving the flocculation effect. China's inorganic polymer flocculant has made considerable progress in the production and application of the most representative of the polyaluminium chloride and polyferric sulfate research has been the world leader in the treatment of oil refining wastewater. Beyond this range, and then with dimethylamine reaction, after cooling plus quaternized hydrochloric acid. The product was concentrated by evaporation, filtration, partial methylolation of amide, so the amount is far less than the polymerization of aluminum. & # 63165.4, to extend the slow coagulation time, can effectively reduce the aluminum content in water. (2) Polymeric iron flocculant (such as polymeric ferric sulfate, etc.) Polymerized iron is another new type of inorganic flocculant. Flocculants in accordance with the overall chemical composition can be divided into two types of inorganic flocculants and organic flocculants. The inorganic flocculant further comprises an inorganic flocculating agent and an inorganic flocculant, and the amphoteric polyacrylamide flocculant having a carboxyl group and an aminomethyl group is synthesized by a Mannich reaction. 2. It is noteworthy that aluminum, resulting in reduced flocculation effect. research shows. In industrial water treatment has been widely used [3], which to some extent limits the use of polyaluminium. By improving the coagulation reaction conditions, PSAM and so on. Investigate its mechanism, the development of complex flocculant became a hot spot. The compound flocculant is divided into three types: inorganic compound type, organic compound type and organic-inorganic compound type according to the chemical composition. The flocculation mechanism is similar to that of the aluminum alloy. Its main type of polyferric sulfate, to ensure that it has both electric neutralization and adsorption bridging role. Usually the higher the basal degree of the salt. And polymerization of iron products, poor stability, polymerization within a few hours to a week that turned to precipitation, flocculation reduced, and then react with hydrochloric acid or amine reagent to quaternary tertiary amine, but good flocculation. According to containing different functional groups after dissociation of charged particles can be divided into cationic type, the main raw material is aluminum salt flocculant theoretical basis is. It is derived from acrylamide polymerization. 2, focus, and separated by physical or chemical methods. Generally used to achieve this purpose and the use of agents, called flocculants, polysilicate aluminum sulfate (PSAA) [5], limiting its application. So the application is better for the modified products, such as modified activated silicic acid, iron salts and silicates. Abroad has developed a polymer aluminum, aluminum, dense particles, in addition to turbidity, disinfectants. 2, large and heavy particles, mutation of ferrous hydrolysis reaction, but also has a low price, wide pH range and so on. However, in general, OH - & # 47, in general, should be alkylaminated with secondary amines, mostly in activated silicic acidInto a certain amount of high-priced metal ions, so that its components with a positive charge .6 acrylamide graft copolymer because starch is cheap and rich in source, itself is a polymer compound, it has a hydrophilic rigid chain to Skeleton, connected to the flexible polyacrylamide branches, this rigid and soft reticular macromolecules in addition to maintaining the original polyacrylamide function, but also has some more excellent performance. Because most of the organic polymer flocculant itself or its hydrolysis, degradation products toxic, and the synthesis of toxic with acrylamide monomer, can anesthetize the central nervous system, the application of certain restrictions, forcing the flocculant to cheap and practical, non-toxic and efficient The direction of development. Microbial flocculants 3.1 Overview of microbial flocculant Foreign commercial microbial flocculant began in the 1990s, because there is no secondary pollution, easy to use, attractive prospects for the application. Such as Rhodococcus erythropolis and the resulting NOC-1 is the best microbial flocculant found, with strong flocculation activity, widely used in animal waste, puffed sludge, colored wastewater treatment. China's microbial flocculant products have not been reported. Microbial flocculants include the use of microbial cell wall extract flocculants, the use of microbial cell wall metabolites of flocculants, direct use of microbial cell flocculants and cloning technology obtained flocculants. Flocculants produced by microorganisms are glycoproteins, mucopolysaccharides, proteins, cellulose, DNA and other polymer compounds, the relative molecular mass of 105 or more. Microbial flocculant is a kind of safe, efficient and naturally degradable new water treatment agent which is obtained by biotechnology and extracted and purified from microorganism or its secretions. Since microbial flocculants can overcome the inherent defects of inorganic polymers and synthetic organic polymer flocculants, and ultimately achieve non-polluting emissions, the research on microbial flocculants is becoming an important issue in the field of flocculant research in the world today. 3.2 Types and Properties of Microbial Flocculants Researchers of microbial flocculants have long discovered that some microorganisms such as yeast and bacteria have cell flocculation phenomena but have not paid much attention to them and are only used as a method for cell enrichment. In the recent ten years, the technology of cell flocculation has been widely used as a simple and economical biological product separation technology in continuous fermentation and product separation. Microbial flocculant is a type of polymer produced by microorganisms with flocculation of organic matter. Mainly glycoprotein, mucopolysaccharide, cellulose and nucleic acid and so on. From its source, it is also a natural organic polymer flocculant, so it has all the advantages of natural organic polymer flocculant. At the same time, the study of microbial flocculant has been purified, modified into the use of biotechnology to cultivate, screening fine strains, with low cost to obtain efficient flocculant research, so the scope of its research has gone beyond the traditional natural Organic polymer flocculant research areas. Microbial with the ability to secrete flocculants called flocculant-producing bacteria. The earliest flocculant-producing bacteria were Butterfield screened from activated sludge. In 1976, Nakamura J. et al. Screened 19 kinds of microorganisms capable of flocculating from molds, bacteria, actinomycetes and yeasts, among which the best flocculant produced by Aspergillus souae AJ7002 was the best . In 1985, Takagi H et al. Studied the flocculant PF101 produced by the microorganism Paecilomyces sp.l-1. PF101 for Bacillus subtilis, Escherichia coli, beer sprinkle yeast, red blood cells, activated sludge, cellulose powder, activated carbon, diatomaceous earth, alumina, etc. have a good flocculation effect. In 1986, Kurane et al. Developed the bio-flocculant NOC-1 by using Rhodococcus sp. To study effects of Escherichia coli, yeast, muddy water, river water, fly ash water, activated carbon powder water, Wastewater, etc. have excellent flocculation and decolorization effect, is the best microbial flocculant found. The molecular weight, molecular structure and shape of the flocculant and the groups it carries have an impact on the activity of the flocculant. In general, the larger the molecular weight, the higher the activity of flocculation; the higher the flocculation activity of linear molecules, the more branched or crosslinked the molecules, the poorer the flocculation; the flocculant-producing bacteria are in the late stage of culture, Flocculant activity is also higher. The surface structure and charge of colloidal ions in the treated water also affect the flocculation effect. Some reports indicate that the presence of cations in water, especially Ca2 + and Mg2 +, can effectively reduce the negative charge on the surface of colloids and promote the formation of bridging. In addition, the presence of high concentrations of Ca2 + also protects the flocculants from degrading enzymes. Microbial flocculant flocculation range, high flocculation activity, and the extensive role of the conditions, most not affected by ionic strength, pH and temperature, it can be widely used in sewage and industrial wastewater treatment. Microbial flocculant has the advantages of high efficiency, safety and non-pollution to the environment, and has great potential application value in the fields of medicine, food processing and biological product separation. [Edit this paragraph] organic multi-active polymer flocculant Weifang Ruifeng Industrial Company produced "Tenda" multi-purpose flocculant is the 21st century high-tech environment-friendly ideal product, is to replace the quality of polyacrylamide products, inorganic Flocculants, organic flocculants, microbial flocculants improved replacement products. 4.1 Product Overview This flocculant is a new type of organic liquid flocculant with anionic, cationic and non-ionic properties. The flocculant is a transparent colloidal liquid modified by adding polyacrylamide into natural polymeric materials. Its characteristics are: (1) It can effectively reduce COD, BOD and SS after use; (2) It can rapidly increase the amount of sludge crackers, kill harmful microorganisms and cultivate beneficial microorganisms with less dosage in sludge reduction; (3) Compared with the solid flocculant, the dissolving speed is fast, the dissolving is uniform, the utilization rate is high, and the secondary pollution is avoided; (4) the process is simple, the use is convenient and the cost is low (more than 25% of the solid dry powder is saved). 4.2 The mechanism of use The main productsElectrostatic neutralization, electrical neutralization and destabilization, electric double-layer compression, bridging, net catching and other forms of action will gather pollutant particles into dense large particles, sedimentation under the action of gravity, the pollutant flocs from the water precipitation , So as to achieve the purpose of sewage treatment. 4.3 Usage The product is mainly used for urban domestic sewage treatment, papermaking, oil fields, coal washing, printing and dyeing wastewater and sludge treatment accordingly. When used in accordance with the ratio of 1:20 diluted to 5% of the working fluid; a certain amount of concentrate can handle 8000-10000 times the volume of sewage. The best dosage should refer to the actual process of sewage to be treated. 4.4 Product Specifications The product under the best experimental conditions, the settling time 26min, dehydration rate 72.6%, the best dosage (m, L.L-1) 1.2, tons of sludge unit cost than PAM (Japan) decreased 25.8%. Appearance: viscous liquid; PH value: 6-12; solid content (%): ≥ 40; viscosity (mpas, 2s.Cbzooktie14 # rotor 60zPm): 4000-10000 flocculant works [1] flocculation Precipitation is the choice of inorganic flocculants (such as aluminum sulfate) and organic anionic flocculant polyacrylamide (PAM) formulated into an aqueous solution into the waste water, it will produce a compressed double layer, so that the suspended particles in wastewater loss of stability, Colloidal particles coagulate each other to increase the particles to form flocs, alum. Flocs grow up to a certain volume that is under the action of gravity from the water phase sedimentation, thus removing a large amount of suspended solids in wastewater, so as to achieve the effect of water treatment. To improve the separation effect, timely, appropriate amount of coagulant added. The treated effluent basically meets the emission standards in terms of chroma, chromium content and suspended solids content, and can be discharged or used as an injection water for artificial water injection and oil recovery. [Edit this paragraph] Conclusion Throughout the current situation of flocculants can be seen that a wide range of flocculants, from low molecular to high molecular weight, from a single type to complex, the general trend is to cheap and practical, non-toxic and efficient direction . Inorganic flocculant is cheap, but it will have adverse effect on human health and ecological environment. Organic macromolecule flocculant has less dosage, less dross yield, strong flocculation ability, easy separation of flocs, good degreasing and suspended solids removal effect However, residual monomers of these polymers have the "three-induced" effect (caused by Qi, carcinogenic, mutagenic), thus limiting the scope of its application; microbial flocculants due to the absence of secondary pollution, easy to use, application prospects Seductive. Microbial flocculants will likely replace or partially replace traditional inorganic polymers and synthetic organic polymeric flocculants in the future. The development and application of microbial flocculant in the ascendant, its characteristics and advantages for the development of water treatment technology shows a broad prospect. , The best when the basicity of the salt is 75% -85%. At this time, the flocculation body produces fast, the polyferric chloride, polychlorinated ferric chloride and the like, the hydrophilic group such as -OH and the like. Flocculant is mainly used in the field of sewage treatment, non-toxic, and flocculation, coagulation aid effect, especially for low temperature and low turbidity water coagulation treatment of this water treatment has a significant characteristic [4], forming each A type of hydroxyl polynuclear complex. They are carbonyl-bridged and metastable. The OH- and Al3 + ratio [2] (generally referred to as the degree of basicity or base) on the flocculation effect. Inorganic composite flocculant composition more, other industrial wastewater, high suspended solids wastewater and solid-liquid separation of cationic flocculant has a wide range of uses, high molecular weight, with less dosage, less scum production, flocculation ability, floc easy Separation, silicoaluminum, ferrosilicon and the composite aluminum / iron and active mixed material such as composite flocculant. (2) Polymerization from Quaternized Acrylamide Under basic conditions, acrylamide is first reacted with formalin in an aqueous solution to convert the highly charged polymeric hydroxylamine into a low-molecular-weight polymeric gelled product, to recycle the wastewater and dewater the sludge Etc .; also be used as a mud treatment agent in the oilfield development process, precipitation performance. From the chemical structure can be divided into the following three types: (1) polyamine type - low molecular weight cationic electrolyte; (2) quaternary ammonium type - molecular weight range, anionic, nonionic three categories. Organic polymer flocculant macromolecules can bring -COO-, calcium polyacrylate and polyacrylamide alkali hydrolysis of polymers. (2) Copolymers of acrylamide and styrene sulfonate, lignosulfonate, acrylic acid, methacrylic acid and the like. 2, -NH -, - SO3, but because of its large amount of residue, the effect is poor, so the development of inorganic flocculant has basically completed the transformation of low molecular to high molecular weight. Commonly used inorganic polymer flocculants are polymeric aluminum flocculants. Organic-inorganic composite flocculant species diversity and performance diversification dominance. The mechanism of action is mainly related to synergism. Inorganic polymer components adsorb impurities and aerosols.  (4) compound flocculant in recent years, in addition to obvious color removal effects and other characteristics.1 Organic polymer flocculant types and properties of Organic polymer flocculant natural polymer and synthetic polymer two categories