Cationic polymeric coagulants

Unlike PA membranes, polyether urea (PEU) membranes are neutral to shghdy positive. PEU (and CA) membranes, unhke aromatic PA membranes, have a smooth surface and are, therefore, less prone to fouling [23], For RO feed water such as surface and municipal water, which are treated with cationic polymeric coagulants, PEU membranes, not negatively charged PA membranes, are used to minimise fouhng. 

Cationic polymeric coagulants have a natural affinity for the negatively-charged polyamide composite membranes, leading to irreversible fouling... 

An alternate and improved means to achieve enhanced coagulation in treating drinking water, a composition for removing turbidity, particles, and color from drinking water, includes (a) primary polymeric coagulant refers to a cationic polymer (a natural, cationic polymer as chitosan or a cationic starch) which enhances the... 

Polymeric coagulants, as stated earlier, are invariably highly cationic in nature, in order that they can neutralise the overall negative charge at the solid-liquid interface. They usually have molecular weights in the order of 250,000 up to 1,000,000. There are a number of different chemical types but the most common are based upon quaternised polyamines, polyDADMAC and polyethyleneimine (PEI). 

Epichlorohydrin Elastomers without AGE. Polymerization on a commercial scale is done as either a solution or slurry process at 40—130°C in an aromatic, ahphatic, or ether solvent. Typical solvents are toluene, benzene, heptane, and diethyl ether. Trialkylaluniinum-water and triaLkylaluminum—water—acetylacetone catalysts are employed. A cationic, coordination mechanism is proposed for chain propagation. The product is isolated by steam coagulation. Polymerization is done as a continuous process in which the solvent, catalyst, and monomer are fed to a back-mixed reactor. Pinal product composition of ECH—EO is determined by careful control of the unreacted, or background, monomer in the reactor. In the manufacture of copolymers, the relative reactivity ratios must be considered. The reactivity ratio of EO to ECH has been estimated to be approximately 7 (35—37). 

Cationic PNIPAM-covered magnetic particles Hetero coagulation of iron oxide nanoparticles onto cationic particles. Encapsulation of preformed particles by polymerization of NIPAM, BAM and AEMH 300-1000 nm Superparamag-netic, bioreactive particles. Temperature, salinity and pH sensitive [10,18,19]... 

SO for several months. The polymeric MnOj consists of roughly spherical particles with a radius of 500 A (50,000 pm or 50 nm) and we determined that the particles are NOT electroactive at the mercury electrode. The material has a negative electrostatic charge and is precipitated as more cations are added, and divalent cations increase the rate of precipitation more than monovalent cations (12). The UV-VIS characteristics are that Beer s law is followed over the pH range used in this study (4-8) at lower pH, the increase in ionic strength causes coagulation and precipitation. Polymeric and soluble Mn02 is a possible product of chemical and bacterial Mn(II) oxidation in fresh waters such as lakes. 

Uses Bactericide, algicide, fungicide, preservative, disinfectant for cosmetics, household disinfectants, foods, beverages, veterinary prods., masonry, swimming pool and industrial water treatment, wood industry, latex coagulation, flotation, electrostatic paints, demulsification of hydrocarbons emulsifier for emulsion polymerization of acrylic monomers Properties Gardner < 2 liq. sp.gr. 980 kg/m solid, pt. -2 to 2 C pH 6-7 cationic 49-51% act. 

The synthetic biocompatible polymer, Jeffamine D2000, which was shown earlier to have interfacial properties [24], was added to the monomer phase to ensure cationic stabilization of the weak spots during the polymerization process. In this case, high solid contents were obtained when adding only small amounts of Jeffamine (0.5 to 2.5 wt.% with respect to the monomer phase), and very small and monodisperse latexes in the size range ca. 100 to 200 nm without any coagulate could easily be synthesized. It is interesting to note that when the Jeffamine con-... 

At about pH 9 the divalent ion is adsorbed and acts as a positive charge site. Coagulation, of course, occurs long before the silica surface is saturated with divalent ions because the divalent ion can act as a bridge by reacting with two particles at their points of contact. For example, Tadros and Lyklema (255) studied the adsorption of calcium ions at various pH, and showed that for each Ca ion adsorbed, there was induced in the silica surface only 1 ds 0.05 OH ion in the pH range 8-9. The calcium ions do not appear to form polymeric cationic species as do trivalent metal ions such as AF. ... 

Organic cationic compounds that are polymeric or are surface-active by having large hydrocarbon groups attached can coagulate silicate ions and silica particles over a wide pH range. 

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