Removal from water

The energy requirements for desorbing 1,1-dichloroethane from activated carbon in a stripping—adsorption process for water purification have been calculated at 112 kj/kg (14). Chlorinated hydrocarbons such as 1,1-dichloroethane may easily be removed from water by air or steam stripping. 

Immiscible wetting in mixers Sol-gel processes Pellet flocculation <0.3 Low Up to 10 ton/hr Wet processing based on flocculation properties of particulate feed Coal fines, soot and oil removal from water Metal dicarhide, silica hydrogels Waste sludges and slurries... 

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. 

When we refer to water purification, it makes little sense to discuss the subject without first identifying the contaminants that we wish to remove from water. Also, the source of the water is of importance. Our discussion at this point focuses on drinking water. Groundwater sources are of a particular concern, because there are many communities throughout the U.S. that rely on this form. The following are some of the major contaminants that are of concern in water purification applications, as applied to drinking water sources, derived from groundwater. 

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 ... 

Polymer A chemical formed by the union of many monomers (a molecule of low molecular weight). Polymers are used with other chemical coagulants to aid in binding small suspended particles to form larger chemical floes for easier removal from water. All polyelectrolytes are polymers, but not all polymers are polyelectrolytes. 

The figures reported in Table 13 represent an optimum quality target for industrial production of FAES. Nevertheless, the Dryex system affords the possibility of further reducing the content of 1,4-dioxane to below the limit of 10 ppm (referred to 100% AM content). In this case, the Dryex system operates as a stripper of the H20/dioxane mixture, being the physical and chemical characteristics of dioxane allow its removal from water solution at reduced pressure with relative ease. 

Sudhakar Y, Dikshit AK. 1999. Adsorbent selection for endosulfan removal from water environment. J Environ Sci Health B 34(1) 97-118. 

W-nitrosodiethylamine from soil by wheat, barley and several vegetable crops has been demonstrated (17,18). Rapid disappearance of the N-nitrosoamine absorbed by plants was observed. Sander et al. (19) observed that several W-nitrosoamines could be removed from water by cress, but the residues rapidly decreased when W-nitrosamine containing water was replaced with non-contaminated water. Dean-Raymond and Alexander (20) reported... 

Petroleum spillages can be removed from water surfaces more efficiently with the following detergent mixture [1692], which contains mainly oxyethyl-ate fatty Cio to C20 alcohols and additional oxyethylated fatty Cn to Cyj acids with an oxyethylene chain length of one to two units. It is used in the form of an aqueous 20% to 25% emulsion, which is sprayed onto a contaminated surface. 

In general, radium - a decay product of uranium - is the critical contaminant which controls the suitability for release of the treated water. Radium is relatively easily removed from water. 

Atwood DA, Zaman MK (2006) Mercury Removal from Water 120 163-182 Autschbach J (2004) The Calculation of NMR Parameters in Transition Metal Complexes 112 1-48... 

Spirodela intermedia, L. minor, and P. stratiotes were able to remove Pb(II), Cd(II), Ni(II), Cu(II), and Zn(II), although the two former ions were removed more efficiently. Data fitted the Langmuir model only for Ni and Cd, but the Freundlich isotherm for all metals tested. The adsorption capacity values (K ) showed that Pb was the metal more efficiently removed from water solution (166.49 and 447.95 mg/g for S. intermedia and L. minor, respectively). The adsorption process for the three species studied followed first-order kinetics. The mechanism involved in biosorption resulted in an ion-exchange process between monovalent metals as counterions present in the macrophytes biomass and heavy metal ions and protons taken up from water.112... 

Mohan, D. and Pittman, C.U., Arsenic removal from water/wastewater using adsorbents—a critical review, Journal of Hazardous Materials, 142 (1-2), 1-53, 2007. 

The radical intermediates "P can couple with each other, leading to the formation of polymeric precipitates that can be readily removed from water (see Figure 17.2). The polymerization of the free radicals is known to be extremely fast, and it is therefore not included in the above reaction scheme. 

Surface water half-lives for removal from water column at 25°C in midsummer sunlight were, t,/2 = 10.5 h for deep, slow, somewhat turbid water t,/2 = 21.6 h for deep, slow, muddy water t,/2 = 8.5 h for deep, slow, clear water t,/2 = 3.5 h for shallow, fast, clear water and t,/2 = 1.4 h for very shallow, fast, clear water (Southworth 1977, Herbes et al. 1980) ... 

Aquaclaus A modification of the Claus process in which hydrogen sulfide is removed from water by reaction with sulfur dioxide. Developed by Stauffer Chemical Company and operated by the Heflin Oil Company, in Queen City, TX. 

See also Borates Boric acid Sodium borates boron oxides, 4 246-249 boron oxides table,4 242t environmental concerns, 4 284—285 health and safety factors, 4 285-288 occurrence, 4 245—246 Boron perchlorates, 18 278 Boron phosphate, 4 242t, 283 Boron removal, from water, 14 418 Boron-stabilized carbanions, 13 660-661 Boron subhalides, 4 141 Boron suboxide, 4 242t Boron tribromide, 4 138 manufacture, 4 145—146 physical properties of, 4 139-140t, 325 reactions, 4 141 specifications, 4 147t uses of, 4 149 Boron trichloride, 4 138 manufacture, 4 145—146 physical properties of, 4 139-140t reactions, 4 141... 

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... 

TESTING OF SORPTION MATERIALS FOR ARSENIC REMOVAL FROM WATERS... 

The granular cast iron of the company ERVIN AMSTEEL was chosen to include another type of material, having been described for arsenic removal from water [3,4] before. 

The removal of metal ions from waste aqueous solutions is of importance to many countries of the world both environmentally and for water re-use. The application of low-cost sorbents including carbonacceous materials, agricultural products and waste by-products has been investigated [1], Several researchers employing wide variety techniques have attempted removal of metal ions from contaminated water bodies. Majorities of these are adsorption on various surfaces. In recent years, agricultured by products have been widely studied for metal removal from water. These include peat [2], pine bark [3], banana peat [4], peanut shells [5], sawdust [6] and leaves [7]. 

Under normal conditions, matter can appear in three forms of aggregation solid, liquid, and gas. These forms or physical states are consequences of various interactions between the atomic or molecular species. The interactions are governed by internal chemical properties (various types of bonding) and external physical properties (temperature and pressure). Most small molecules can be transformed between these states (e.g., H2O into ice, water, and steam) by a moderate change of temperature and/or pressure. Between these physical states— or phases—there is a sharp boundary phase boundary), which makes it possible to separate the phases—for example, ice may be removed from water by filtration. The most fundamental of chemical properties is the ability to undergo such phase transformations, the use of which allows the simplest method for isolation of pure compounds from natural materials. 

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