Wastewater treatment, foam

Uses Dispersant emulsifier for latex polymerization, wastewater treatment foam-able hydrophilic prepolymer for wound dressings, biocompalible coatings, dmg delivery vehicles absorbent foam, carrier food-contact PU, rubber articles Manuf/Distrib. Air Prods. Bayer Chemtura Cylec Conap DSM NeoResIns Huntsman Polyurethanes Monomer-Polymer Dajac Labs Polyurethane Coqp. of Am. Soluol Vertellus Perf. Materials Polyurethane resin Synonyms Polyurethane polymer PU Classification Urethane... 

Foam Fractionation. An interesting experimental method that has been performed for wastewater treatment of disperse dyes is foam fractionation (88). This method is based on the phenomenon that surface-active solutes collect at gas—Hquid iaterfaces. The results were 86—96% color removal from a brown disperse dye solution and 75% color removal from a textile mill wastewater. Unfortunately, the necessary chemical costs make this method relatively expensive (see Foams). 

An important number of these substances have an industrial origin. Some of them, like the pesticides, arrive intentionally in the environment and their use and release should be theoretically controlled. However, many of them have not been purposely produced as bioactive substances but more as components or additives of certain materials. Their significant growth in the chemical industry has not only been produced as a consequence of the discovery of new active principles in the pharmaceutical or pesticide area, but also because of the expansion of new technologies (electronics, containers, textiles, plastics, resins, foams, etc.), that require the development of new materials and substances with particular features. Most of these substances enter or are discharged to water and air sources without regulated controls. Wastewater treatment plants (WWTPs) are often not yet adapted to completely remove them, and therefore these new compounds can be found to some extent in wastewater effluents as well as in soil and sludge. 

In general, the main pollution problems associated with surfactants can be summarized as (1) foaming in river and wastewater treatment plants [314,326, 344,348,349,356,357], (2) transformation to bioactive metabolites (i.e., poly-ethoxylated alkylphenols, estrogenic compounds) under aerobic and anaerobic conditions [315,356], and (3) formation of certain cationics which are toxic to microorganisms at high concentrations [356,357]. 

In many cases, foaming is found to be undesirable (such as in dishwashing and wastewater treatment), and in many industries, such as in wastewater treatment, all foaming needs to be eliminated. The main criteria for antifoaming molecules have the following characteristics ... 

LINPOR [LINde PORous medium] A biological wastewater treatment process, using an open-pore plastic foam for retaining the biomass. Its use enables the capacity of an activated sludge plant to be increased without adding extra tanks. Invented at the Technische Universitat, Munich, and further developed by Linde, Munich. See also CAPTOR. 

The experiments have proved that membrane distillation can be applied for radioactive wastewater treatment. In one-stage installation the membrane retained all radionuclides and decontamination factors were higher than those obtained by other membrane methods. The distillate obtained in the process was pure water, which could be recycled or safely discharged into the environment. It seems the process can overcome various problems of evaporation such as corrosion, scaling, or foaming. There is no entrainment of droplets, which cause the contamination of condensate from thin-film evaporator. Operation at low evaporation temperature can decrease the volatility of some volatile nuclides present in the waste, such as tritium or some forms of iodine and ruthenium. The process is especially economic for the plants, which can utilize waste heat, e.g., plants operating in power and nuclear industry. 

Flotation is the term used to describe a process in which the species being separated from the bulk liquid media are insoluble particulates. Froth flotation is another one of the two foam separation processes. It also involves the production of foam in a heterogeneous aqueous system, and has a great deal of potential for the water and wastewater treatment. Froth flotation can be subdivided into at least seven categories (42,43,84), including precipitate flotation, ion flotation, molecular flotation, microflotafion, adsorption flotation, ore flotation, macroflotation, and adsorbing colloid flotation. They are described separately below. 

There are many methods for the desulfurization of nature gas, which can be classified into dry desulfurization, wet desulfurization, and catalytic adsorption. In the dry desulfurization, some solid sorbents, such as iron oxide, zinc oxide, activated carbon (AC), zeolites, and molecular sieves, are used. In wet desulfurization method, liquid-phase chemical/physical solvent absorption systems are usually used for scrubbing H2S amine-based processes are subject to equipment corrosion, foaming, amine-solution degradation, and evaporation, and require extensive wastewater treatment. As a result, this sulfur removal technology is complex and capital intensive,44 although the processes are still employed widely in the industry. The desulfurization of coal gasification gas will be reviewed in detail in Section 5.5. In the catalytic-adsorption method, the sulfur compounds are transformed into H2S by catalytic HDS or into elemental sulfur or SOx by selective catalytic oxidation (SCO), and then, the reformed H2S and SOx are removed by the subsequent adsorption. 

On the other hand, tensides can increase the share of non-sedimentable substances in sewage waters due to their dispersing and emulsifying effects. In the biological section of a wastewater treatment plant, particularly nonionic tensides can cause other difficulties (excessive foaming in the activation reservoirs, foam stabilization, etc.). 

Chem. Descrip. Dimethylaminoethyl methacrylate CAS 2867-47-2 EINECS/ELINCS 220-688-8 Uses Detergent and sludge dispersant in lubricants vise, index improver flocculant for wastewater treatment retention aid for paper mfg. acid scavenger in PU foams corrosion inhibitor resin and mbber modifler used in acrylic polishes and paints, hair prep, copolymers, sugar clarification, adhesives, water clariflcation, acrylic plastics for food pkg. Regulatory FDA 21CER 177.1010... 

Uses Defoamer for emulsion paints, emulsion polymers, syn. renderings, food pkg. adhesives/coatings/paper, coaling colors (graphic papers), wastewater treatment Features Prevents and combats surf, foam Re latory FDA 21CFR 175.105,175.300,176.200,176.210 BGAcom-pliance... 

Uses Foam control agent for food industry, fermentation, high sugar-content processes, paper coatings, wastewater treatment, heating/cooling water treatment... 

Uses Foam control agent tor distillation, glycol scrubbing, detergents, wastewater treatment, adhesives/coatings, resin and textile sizes, metalworking, and paper/printing industries Properties Thin wh. cream nonionic 10% act. 

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