Synthetic water treatment polymers

Synthetic water treatment polymers were first introduced in the 1950s. The first important synthetic polymers included hydrolyzed polyacrylamide and various high molecular weight (100,000+) homopolymers of polyacrylic acid and polymethacrylic acid, together with their sodium salts. 

The increase in size of water consumption and decrease of water quality due to man s impact make the problem of water purification and treatment from different contaminants, such as suspended and colloidal disperse particles, more acute. The efficiency of dispersion precipitation can be greatly improved with the use of flocculants - high-molecular compounds that have the ability to adsorb themselves on disperse particles and form fast precipitating aggregates [1], Both natural and synthetical water soluble polymers can be used as flocculants. The most commonly used and the most active of these polymers are polyacrylamide (PAA) and some of its derivatives. 

Saccharides have a number of attributes that make them very attractive as raw materials for the synthesis of polymers. The confluence in saccharides of different functionalities such as multiple hydroxyl groups and latent reactivity, which is difficult to realize in wholly synthetic materials, is of particular interest to us. The preparation of monomers derived from saccharides and the subsequent polymerization of these materials is one approach that has been extensively pursued as a means to introduce saccharide groups into synthetic polymers (1-9). With a few exceptions (2), most of this previously reported work has involved attaching a polymerizable moiety onto a mono- or disaccharide. The practical synthesis of a new family of monomers derived from carbohydrates ranging from monosaccharides to large oligosaccharides and the use of these monomers to produce a detectable water treatment polymer are described in this paper. 

The same questions about the safety of organic flocculants have been raised ia other countries. The most drastic response has occurred ia Japan (7,77) and Swit2edand (77) where the use of any synthetic polymers for drinking water treatment is not permitted. Alum and PAC are the principal chemicals used ia Japan (7). Chitin, a biopolymer derived from marine animals, has been used ia Japan (80,81). Maximum allowed polymer doses have been set ia Prance and Germany (77). 

The addition of water-soluble polymers such as polyethylene oxide (PEO) or polyvinyl alcohol (PVA) into the synthetic mixture of the C TMAX-HN03-TE0S-H20 system (n = 16 or 18 X = Br or Cl) under shear flow is found to promote uniformity and elongation of rope-like mesoporous silica. The millimeter-scaled mesoporous silica ropes are found to possess a three-level hierarchical structure. The addition of water-soluble polymer does not affect the physical properties of the silica ropes. Moreover, further hydrothermal treatment of the acid-made material under basic ammonia conditions effectively promotes reconstruction of the silica nanochannels while maintaining the rope-like morphology. As a result, a notable enhancement in both thermal and hydrothermal stability is found. 

The same questions about the safely of organic flocculants have been raised in olher countries. The most drastic response has occurred in Japan and Switzerland w here the use of any synthetic polymers for drinking water treatment is not permitted... 

One of the prime environmental objectives is the removal of suspended contaminants from water and waste streams. Water turbidity in nature is the result of colloidal clay dispersion and the color is from decayed wood and leaves (tannins and lignins) and organic soil matter. In addition to these contaminants, there are viruses, algae, bacteria, metal oxides, oils and other pollutants. In recent years, synthetic organic polyelectrolyes, in particular the cationic polymers, have been used very effectively in water treatment (3). These polyelectrolytes are high... 

Synthetic cationic polymers have been used in water-based drilling fluids to control shale problems. Recent applications include the use of low molecular weight poly amines (48, 49) some of these cationic polymers are also used for water treatment (48). The use of low molecular weight polyols and glycols has recently been advocated with claims that they act to control both fluid loss and shale hydration (50). 

Synthetic water soluble/swel1 able polymers have commercial importance in such application as water treatment, cosmetics, and foods. Yet, these... 

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