Adsorption by organic matter

Emissions of silver from coal-fired power plants may lead to accumulations in nearby soils (Fowler and Nordberg 1986). Silver in soils is largely immobilized by precipitation to insoluble salts and by complexation or adsorption by organic matter, clays, and manganese and iron oxides (Smith and Carson 1972). 

Adsorption by organic matter is a key factor in the behavior of many compounds introduced into soils and sediments as pesticides or noxious waste organic chemicals. Bioactivity, persistence, biodegradability, teachability. 

PROBABLE FATE photolysis, photolysis is slow but is the principal fate of the compound, atmospheric and aqueous photolytic half-life 0.17-1 hrs, will quickly photolyze in the atmosphere, estimated half-life with hydroxyl radicals 4.03 days oxidation , not important, photooxidation half-life in air 2.66-26.6 hrs hydrolysis , not important volatilization no loss to volatilization is reported, will rapidly volatilize if released to the surface of soils sorption moderate adsorption by organic matter is possible, not expected to sorb strongly to organic matter if released to soil, if released to water, there is a slight tendency biological processes , not important... 

The amount of Mo adsorbed has been found to be closely related to the soil s organic-matter content (Karimian and Cox, 1978). Because Mo acts as an anion in the soil, it is difficult to explain its adsorption by organic matter. However, certain soils high in organic matter have been found to be deficient in Mo (Mulder, 1954 Davies, 1956). Mulder (1954) found pronounced responses to added Mo in several crops grown on soils with high amounts of organic matter. 

Ward and Upchurch (340) found an inverse relationship between the solubilities of 18 substituted anilines and their adsorption by nylon (R2 = 0.77) and cellulose triacetate (R = 0.80). It was suggested that steric and electronic effects of the molecules were also responsible for the adsorption differences of the compounds. Because of the low solubilities of the substituted anilines, adsorption by organic matter probably occurs at lipophilic sites through dipole-dipole interactions—e.g., hydrogen bonding or charge-transfer complexes. Low adsorption at clay surfaces probably occurs because the hydrophobic molecules do not readily associate with hydrated surfaces. Adsorption of the substituted anilines by dry clays might occur on the soil surface for instance, but in the... 

Adsorption by organic matter or hving plants and animals and... 

Activated carbon filters remove a wide range of organic matter by adsorption onto the carbon bed. The bed may be derived from a number of different carbon sources, and the correct selection of bed type, capacity, and porosity is a specialized function. Activated carbon may be usefully employed in organic traps, complementing the resin bed, but its capacity and organic removal rate characteristics are flow-dependent. Excessive flows may compromise the rate of adsorption of organic matter. 

Before analysis of semi- or nonvolatile components can proceed, it is necessary that the hydrocarbon components be brought into solution. In a sample from a contaminated site, semi- and nonvolatile molecules may exist in the soil pores in the free form within the pore spaces, but are far more likely to be adsorbed by organic matter attached to the soil. Indeed, the probability of such adsorption increases with increasing hydrophobicity of the molecules. 

Carringer, R.D., J.B. Weber, and TJ. Monaco (1975). Adsorption-desorption of selected pesticides by organic matter and montmorillo-nite. J. Agric. Food Chem., 23 568-512. 

The ability to control NOM adsorption through modification of surface chemistry was demonstrated previously [20] the uptake of several model humic substances and natural organic matter isolated from surface waters decreased significantly with increasing surface acidity (as measured by NaOH neutralization). The uptake was partially restored by subsequent heat treatment of the oxidized surfaces (i.e. OX 9/70 HT650). For the wood-based carbons, the impact of surface treatment on adsorption of organic matter was surprisingly small or absent. Overall, the reactivity of carbon surfaces to DOM uptake depended on the raw material type, activation conditions and surface treatment. 

In this paper the adsorption of organic matter on activated caii>on from primary microbiologically treated mixtures of oil refinery and municipal wastewaters, as well as its simultaneous desorption by microbiological oxidation is considered. It has been established that the denitrification bacteria use the adsorbed organic matter as a carbon source in the denitrification process. In this way a bioregeneration of the activated carbon has been achieved, as well as the control of organic and nitrate load in the effluent. 

The objective of the present work is to investigate the process of continuous adsorption of organic matter from the biologically treated mixtures of wastewaters from an soil refinery and a municipal source on activated carbon, which is accompanied by its desorption via biodegradation. 

The adsorption capacity of activated carbon was determined under static conditions by adsorption of organic matter from the microbiologically pretreated wastewater mixture. 

This section aims to give an overview of adsorption processes of metal ions by activated carbon. Three cases are detailed (1) the adsorption of metal ions onto virgin activated carbon adsorption capacities are given in static and dynamic reactors, and the influence of various operating conditions is shown (2) the adsorption of metal ions onto activated carbon preloaded with organic matter (3) the saturation of activated carbon by organic matter and metal hydroxides after its use in wastewater treatment. The influence of metal hydroxides on activated carbon regeneration is demonstrated. 

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