Organics removal from water

Yamaguchi, T., Tominaga, A., Nakao, S. and Kimura, S. 1996. Chlorinated organics removal from water by plasma-graft filling polymerized membranes. 42(3) ... 

Pervaporation membranes are of two general types. Hydrophilic membranes are used to remove water from organic solutions, often from azeotropes. Hydrophobic membranes are used to remove organic compounds from water. The important operating charac teris-tics of hydrophobic and hydrophihc membranes differ. Hydrophobic membranes are usually used where the solvent concentration is about... 

Adsorption — An important physico-chemical phenomenon used in treatment of hazardous wastes or in predicting the behavior of hazardous materials in natural systems is adsorption. Adsorption is the concentration or accumulation of substances at a surface or interface between media. Hazardous materials are often removed from water or air by adsorption onto activated carbon. Adsorption of organic hazardous materials onto soils or sediments is an important factor affecting their mobility in the environment. Adsorption may be predicted by use of a number of equations most commonly relating the concentration of a chemical at the surface or interface to the concentration in air or in solution, at equilibrium. These equations may be solved graphically using laboratory data to plot "isotherms." The most common application of adsorption is for the removal of organic compounds from water by activated carbon. 

A final are we should discuss is color removal. This is perhaps the most difficult impurity to remove from waters. In surface waters color is associated with dissolved or colloidal suspensions of decayed vegetation and other colloidal suspensions. The composition of this material is largely tannins and lignins, the components that hold together the cellulose cells in vegetation. In addition to their undesirable appearance in drinking water, these organics can cause serious problems in downstream water purification processes. For examples ... 

Tubular reactors are used for reactions involving a gas and a liquid. In this arrangement, the gas phase is dispersed as bubbles at the bottom of a tubular vessel. The bubbles then rise through the continuous liquid phase that flows downwards as shown in Figure 4-14. An example of this process is the removal of organic pollutants from water by noncatalytic oxidation with pure oxygen. 

Flocculation or clarification processes are solids-liquid separation techniques used to remove suspended solids and colloidal particles such as clays and organic debris from water, leaving it clear and bright. Certain chemicals used (such as alums) also exhibit partial dealkaliz-ing properties, which can be important given that the principal alkaline impurity removed is calcium bicarbonate—the major contributory cause of boiler and heat exchanger scales (present in scales as carbonate), although closely followed by phosphate. 

For removal of an organic component from water, swelling of the organophillic membrane would result in a higher flux and lower a. At organic levels below about 10 percent, that has not been a major... 

The efficiency of type II organoclays in taking up organic pollutants from water is also apparent from the data in Figs. 7 and 8 showing the removal of naphthalene and 17P-estradiol (an endocrine-disrupting compound) by octadecyltrimethylammonium-montmorillonite (Yuan 2004). 

Refractory organics, removal from drinking water, 17 806... 

Organo-modified natural zeolites as new tailored natural materials for removal of cations, anions and even organic pollutants may present fairly large potential for water utility companies. The topic of this study was to examine the oxyanions removal from waters by octadecylammonium-enriched inland clinoptilolite. The 18-carbon chain consisting surfactant attached on the clinoptilolite surface, as to the organic acids of living bodies comparable substances, makes the treatment process economic on scale and cost-effective as well.7... 

Green Synthesis Of Different Transition Metal Oxide Nanoparticles Potential Catalysts For Removal Of Organic Colorants From Water... 

Bisschops, M. A. T., van der Wielen, L. A. M. and Luyben, K. Ch. A. M. in Semel, J. (ed) Process Intensification in Practice, Applications and Opportunities (BHR Group, London, 1999) 229. Centrifugal adsorption technology for the removal of volatile organic compounds from water. 

Figure 11 Produced water treatment system. Treatment is mainly for oil and organics removal. (From Ref. 9.)...

Acbvated carbon adsorption is most often employed for removal of organic constituents from water and wastewater. Granular acbvated carbon (GAC) or powdered activated carbon (PAC) may be used. Granular activated carbon columns can be used for secondary tteatment of industtial wastewaters or for tertiary tteatment to remove residual organics from biological tteatment effluent. The primary use of PAC in wastewater tteatment has been in the PACT process (Zimpro), in which PAC is added to the acbvated sludge process for enhanced performance. This process is discussed in the next section of this chapter. 

The link between colloids and surfaces follows naturally from the fact that particulate matter has a high surface area to mass ratio. The surface area of a 1cm diameter sphere (4jtr ) is 3.14 cm, whereas the surface area of the same amount of material but in the form of 0.1 pm diameter spheres (i.e. the size of the particles in latex paint) is 314 000 cm. The enormous difference in surface area is one of the reasons why the properties of the surface become very important for colloidal solutions. One everyday example is that organic dye molecules or pollutants can be effectively removed from water by adsorption onto particulate activated charcoal because of its high surface area. This process is widely used for water purification and in the oral treatment of poison victims. 

Activated charcoal or carbon is widely used for vapour adsorption and in the removal of organic solutes from water. These materials are used in industrial processes to purify drinking water and swimming pool water, to de-colorize sugar solutions as well as other foods, and to... 

Phosphates are also problematic. Most phosphates are present in residential water as inorganic phosphates, but organic moieties are common. Biological action converts the various forms into orthophosphates that can be removed from water streams by incorporation into specialized bacteria and algae. 

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