Reaction with organic matter

The thermodynamic properties of U-Th series nuclides in solution are important parameters to take into account when explaining the U-Th-Ra mobility in surface environments. They are, however, not the only ones controlling radionuclide fractionations in surface waters and weathering profiles. These fractionations and the resulting radioactive disequilibria are also influenced by the adsorption of radionuclides onto mineral surfaces and their reactions with organic matter, micro-organisms and colloids. 

Stevenson F.J., Fitch A. Reactions with organic matter . In Copper in Soils and Plants, J.F. Loneragan, A.D. Robson, R.D. Graham, eds. Sydney Academic Press. 1981. 

Many accidents have been reported involving the preparation and the use of this compound. The compound is sensitive to heat and shock. Reactions with organic matter, finely divided metals and other readily oxidizable substances can be violent to explosive. It is a strong irritant to skin, eyes and mucous membranes. 

Vigorous to violent reactions with organic matter.2 Diphenyl Ether. Vigorous interaction above 40°C.3... 

So formed, chlorine dioxide may undergo many chemical or electrochemical reactions. With organic matter it again forms chlorite. If ozone is generated, it reacts in the ms-range with chlorine dioxide in competition with the reaction with active chlorine (Gordon et al. 2002) ... 

Equation 8.9 shows that when NH3 is introduced to an acid solution, it reacts directly with the acid and produces the ammonium ion (NH4) (see Chapter 12). Concurrent with Equation 8.9, NH3 may associate itself with several water molecules (NH3nH20) without coordinating another H+. This hydrated NH3 is commonly referred to as unionized ammonia and is toxic to aquatic life forms at low concentrations. Because NH3 is a volatile gas, some of it may be lost directly to the atmosphere (volatilization) without dissolving in solution. On the other hand, the ammonium ion may undergo various reactions in the soil water that may alter its availability to plants and/or other organisms. These reactions include formation of metal-ammine complexes, adsorption on to mineral surfaces, and chemical reactions with organic matter. 

SAFETY PROFILE Poison by ingestion and intraperitoneal routes. A trace mineral added to animal feeds. Potentially explosive reaction with charcoal + ozone, metals (e.g., powdered aluminum, copper), arsenic carbon, phosphoms, sulfur, alkali metal hydrides, alkaline earth metal hydrides, antimony sulfide, arsenic sulfide, copper sulfide, tin sulfide, metal cyanides, metal thiocyanates, manganese dioxide, phosphorus. Violent reaction with organic matter. When heated to decomposition it emits very toxic fumes of I and K2O. See also lODATES. 

It is particularly hazardous to the eyes because of its ready reaction with organic matter, a property exploited in electron microscopy in order to stain and fix biological tissues. Although osmium is a d8 transition metal, its tetroxide is a coordinatively unsaturated 16-electron species and has a tetrahedral structure3. It is highly soluble in carbon tetrachloride (375 g/ 100 g), less so in benzene, and moderately soluble in water (7.24 g/100 g). 

TBHP may be released to the environment through various waste streams. Chemical degradation is expected to be the dominant fate process in water because of reaction with organic matter and therefore, it is doubtful that unreacted TBHP would be... 

By combining equations 5.22 and 5.23, the overall A1 bonding reaction with organic matter is obtained ... 

Water that is aerated by flowing in shallow streams and rivers is constantly replenished with oxygen. However, stagnant water or that near the bottom of a deep lake is usually almost completely depleted of oxygen because of its reaction with organic matter and the lack of any mechanism to replenish it quickly, diffusion being a slow process due to thermal stratification (Figure 4). 

The presence of hypochlorous acid as opposed to the hypochlorite ion, is responsible for the biocidal activity. Hypochlorous acid is estimated to be twenty times more effective as a micro-biocide than the hypochlorite ion. Unfortunately however, in a cooling tower there is a tendency to strip chlorine from the water by the countercurrent flow of the air, so that Equation 14.23 moves to the left and it is likely that by the time the water reaches the basin of the tower all the chlorine will have been lost to the air in addition to reactions with organic matter within the tower. It will be necessary therefore for maximum utilisation of the available chlorine to ensure that the equilibrium of Equation 14.24, is over to the LHS. Since the ionisation process produces hydrogen ions the equilibrium will be affected by the pH of the solution. The effect of pH on HOCl stability is shown on Fig. 14.16 [Marshall and Bott 1988]. In the figure 100% HOCl indicates that the equilibrium is completely to the left in Equation 14.24 and there is no ionisation of the HOCl. From Fig. 14.16 this condition occurs at pH of around 5. At a pH 7.5 hypochlorite ion and acid co-exist in approximately equal amounts. It nll be seen that as the pH approaches 9 the hypochlorous acid content drops to a very low value and the biocidal effect is negligible. Values of pH lower than around 6.5 are not practical because of the potential risk of corrosion. 

A nitrification inhibitor that is fully effective would be expected to (1) increase efficiency in the use of nitrogen fertilizers, especially on coarse-textured soils where rainfall is high, or extensive irrigation is practiced (2) make more feasible the practice of fall applications of ammonia (3) make less critical the time of nitrogen fertilizer applications and the need for split applications and (4) reduce nitrogen losses that may occur via nitrite decomposition or reaction with organic matter. Whether the benefits to be expected are sufficient to more than offset the costs of the chemical, and the additional steps involved in its use, is a practical matter that must be determined by the user for his particular soil and cropping system. 

The fate of peroxy radicals at sediment or soil surfaces has been considered by Pohlman and Mill (1983). They examined the ability of common soil constituents to quench the reaction of an alkylperoxy radical with a reactive probe molecule, p-isopropylphenol. They found that reactions with organic matter were dominant over possible reactions with the mineral constituents, except for possibly Cu but natural humic materials appeared to be a rather poor scavenger, presumably because the bulk of their structure consisted of unreactive moieties such as polysaccharides and aliphatic chains. They also concluded that phenols and other reactive xenobiotics might be partially susceptible to removal through reaction with these radicals. 

Vairavamurthy M. A., Mopper K. and Taylor B. F. (1992) Occurrence of particle-bonded polysulphides and significance of their reaction with organic matter in marine sediments. Geophys. Res. Lett. 19, 2043-2046. 

Precaution Violent reaction with organic matter explosive reactions possible Hazardous Decomp. Prods. Heated to decomp., emits very toxic fumes of l and K2O HMIS Health 1, Flammability 0, Reactivity 3 Uses Analysis (testing for zinc and arsenic) iodometry reagent food additive (dough conditioner, flour treatment agent) feed additive (trace mineral) medicine (topical antiseptic) oxidation of sulfur dyes Regulatory FDA 21 CFR 136.110, 184.1635, 582.80, GRAS... 

A disadvantage of chlorine is that reactions with organic matter, particnlarly hnmic materials, produce carcinogenic trihalomethanes snch as chloroform and bro-moform. Advantages of chlorine are that the compound... 

Cormix and GEMSS allow the setting of decay terms to depict biocide conversion, e.g. reaction with organic matter. If linear decay does not fit a substantially nonlinear conversion behavior, then only 3D SMART remains a viable choice. 3D SMART can process nonlinear conversion models or operate spline based conversion models. The nonlinear biocide reaction of hypobromous acid with organic matter to form products such as Tribromomethane (TBM) can be simulated by closed form nonlinear models or a spline approximation which fits itself to laboratory measurements. An individual first... 

The most important leachate reactions are dissolution and precipitation of solids and minerals, redox (reduction/oxidation) reactions with organic matter, and ion exchange and sorption on clay minerals and organic matter. 

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