Adsorbents biological activated carbon

The activated carbon is often chosen as granular carrier and is referred to as granular activated carbon (GAC) or biological activated carbon (BAC). This support is characterized by a strong propensity to adsorb the dyes and is a good candidate for biofilm formation, because of its natural organic matrix. The marked propensity to adsorb dyes contributes to increase the tolerance to shock loadings. In fact, under transient conditions the free surface of the AC acts as a temporary buffer for the dye, which is eventually released as dye disappears. 

Poisoning has been traced to adsorption phenomena. Substances that poison biological systems often are well adsorbed on carbon and other adsorbents. The hemolytic activity of alkaline soaps parallels their adsorbability on activated carbon and this is also true of the bactericidal activity of phenyl-substituted acids.9 Narcotics show a similar relation.10 Poisoning in biological systems often can be traced to the adsorption of substances on cell walls. In some instances it ends the flow of materials in and out of the cell in others, adsorption of the poison on active centers prevents the synthesis of vital substances. 

The utility of carbon for the purification of a biological product may depend on the stability of the product while in the adsorbed state. A number of biological products are stable when adsorbed and this is true even of substances that are susceptible to destructive changes. Regna23 reports that penicillin adsorbed on activated carbon is stable for at least 6 hours. Jensen and DeLawder24 found that adsorption on carbon did not alter the activity of crystalline insulin. In some cases, the stability is enhanced in the adsorbed state. Thus, under ordinary conditions, the adrenal cortex hormone is rapidly destroyed when the adrenal glands are removed from the animal body, but when adsorbed on activated carbon, the hormone is stabilized and the product retains its activity indefinitely at room temperature.25... 

Other types of regenerators designed for specific adsorption systems may use solvents and chemicals to remove susceptible adsorbates (51), steam or heated inert gas to recover volatile organic solvents (52), and biological systems in which organics adsorbed on the activated carbon during water treatment are continuously degraded (53). 

Subsequently, biological/physical treatment of leachate with an activated carbon-enhanced sequencing batch bioreactor (PAC-SBR) was analyzed to determine whether the improved treatment by simultaneous adsorption and biodegradation in the SBR would produce an acceptable effluent without post-treatment in the existing granular activated carbon adsorber (Ying et al., 1986). 

The activated carbons obtained have a potential for medical applications in treatment of chemical and biological poisoning as oral adsorbents and in extracorporeal blood detoxication. 

Waste-treatment processes commonly result in the production of solid wastes that must be disposed of safely. Enzymatic treatment is no exception. For example, although enzymatic treatment may not produce as large a quantity of solid products as does biological treatment, some solid residues may be formed, e.g., the polymer precipitates formed during the treatment of phenols with peroxidases, spent adsorbents such as talc, chitin, or activated carbon that are used to eliminate the soluble products of enzymatic reactions, or residues of plant materials such as raw soybean hulls when they are used in place of purified enzymes during treatment. Perhaps, the polymers and adsorbents could be incinerated to recover some energy if the emission of dangerous combustion by-products can be controlled or prevented. The residues of plant materials could potentially be composted and used as soil conditioners, provided that pollutants do not leach from them at substantial rates. To date, none of these disposal problems have been addressed adequately. 

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