Immobilization of hazardous

Immobilization of hazardous reagents and catalysts by attaching active groups to polymeric or immobile backbones. 

Before the injected fluids migrate out of the injection zone or to a point of discharge or interface with USDW, the fluid will no longer be hazardous because of attenuation, transformation, or immobilization of hazardous constituents within the injection zone by hydrolysis, chemical interactions, or other means. 

Production and use of biodegradable containers. Biotechnological formation of chemical substances (H2S, Fe ) used for the collection of hazardous substances. Biotreatment and biodegradation of hazardous waste. Immobilization of hazardous substances from the streams. Solubilization of hazardous substances from waste. Biodegradation of hazardous substances. Immobilization/solubibzation of hazardous substances. Biotransformation and detoxication of hazardous substances. Solubilization/precipitation and recycling of heavy metals from waste. 

Vitrification Various molten-glass processes are commercially available for the destruction and/or immobilization of hazardous wastes (Freeman, 1998). The vitrification method destroys the combustible and some toxic portions of the waste while at the same time incorporating residuals into a glass form. 

Vitrification is effective at destroying and immobilizing hazardous materials, but it is very energy intensive and thus expensive. Consequently, it is used primarily where wastes are difficult to treat or destmction—immobilization of contaminants is very important such as with radionucHdes. 

The general purpose of ultimate disposal of hazardous wastes is to prevent the contamination of susceptible environments. Surface water runoff, ground water leaching, atmospheric volatilization, and biological accumulation are processes that should be avoided during the active life of the hazardous waste. As a rule, the more persistent a hazardous waste is (i.e., the greater its resistance to breakdown), the greater the need to isolate it from the environment. If the substance cannot be neutralized by chemical treatment or incineration and still maintains its hazardous qualities, the only alternative is usually to immobilize and bury it in a secure chemical burial site. 

Behnajady, M.A., Modirshahla, N., Daneshvar, N. and Rabbani, M. (2007) Photocatalytic degradation of C.I. Acid Red 27 by immobilized ZnO on glass plates in continuous-mode. Journal of Hazardous materials, 140, 257-263. 

Cement-based stabiUzation/solidification (S/S) is a technology for the in situ or ex situ treatment of hazardous wastes and hazardous waste sites. It is a process that uses cement and other additives or processes to physically and/or chemically immobilize the hazardous constituents of contaminated soils, sludges, sediments, or liquid wastes. The objective is to prevent the migration of contaminants in the environment by forming a solid mass. 

The HAZCON solidification process is an ex situ technology for the immobilization of metals and inorganic hazardous wastes in wet or dry soil and sludges. The technology is a cement-based process in which the contaminated material is mixed with pozzolanic materials such as Portland cement, a patented additive called Chloranan, and water. The process is capable of treating solids, sludges, semisolids, or liquids. The mixture hardens into a cohesive mass that immobilizes heavy metals. 

Wronkiewicz, D. L., Wolf, S. F. DiSanto, T. S. 1996. Apatite- and monazite-bearing glass-crystal composites for the immobilization of low-level nuclear and hazardous wastes. Materials Research Society Symposium Proceedings, 412, 345-352. 

Shimaoka, T., Oku, K. et al. 1998. Stability of hazardous heavy metals in chemically immobilized fly... 

Theodoratos, P., Papassiopi, N. Xenidis, A. 2002. Evaluation of monobasic calcium phosphate for the immobilization of heavy metals in contaminated soils from Lavrion. Journal of Hazardous Materials, 94, 135-146. 

The issue of proper management of hazardous wastes is one which suffers from much misinformation and confusion. The present chapter reviewed additives and techniques that can be applied to specific solidification problems and immobilization of specific hazardous constituents (e.g., lead and cadmium), including a list of generic additives that can be used to control wastes pH to reduce, oxidize, and co-precipitate constituents and to accelerate/retard set. 

Bonen D, Sarkar SL (1995) The effects of simulated environmental attack on immobilization of heavy metals doped in cement-based materials. J Hazard Mater 40 321-335... 

Boyd, S. A., W. F. Jaynes, and B. S. Ross. 1991. Immobilization of organic contaminants by organoclays Application to soil restoration and hazardous waste contaminants. In R. A. Baker, Ed. Organic Substances and Sediments in Water, Vol. 1. Lewis Publishers, Chelsea, MI, pp. 181-200. 

Hydrophilicity is an important criterion for the use of synthetic polymers. Existing methods for surface modihcation of synthetic hbers are costly and complex. Therefore, the enzymatic surface modihcation of synthetic hbers is a new and green approach to synthesize polymers with improved surface properties. Use of enzymes for surface modihcation of polymers will not only minimize the use of hazardous chemicals but also minimize the environment pollution load. Besides these, the enzyme-modihed polymers can also immobilize those enzymes which can only bind to the selective functional groups present on the polymeric surface such as —COOH and —NH2. Similarly, substrates can immobilize on the solid matrix (or polymer), which will be easily accessible to the enzymes. Genetic engineering can be employed for the modihcation of active sites of enzymes for better polymer catalysis. 

Stabilization is the process used for reduction of hazard potential of the waste by converting the contaminants into their least soluble, least immobile, or least toxic form. Other characteristics of the waste may not change in this treatment. 

As discussed in Chapter 16, chemical stabilization is a result of conversion of contaminants in a radioactive waste into their insoluble phosphate forms. This conversion is solely dependent on the dissolution kinetics of these components. In general, if these components are in a soluble or even in a sparsely soluble form, they will dissolve in the initially acidic CBPC slurry and react with the phosphate anions. The resultant product will be an insoluble phosphate that will not leach into the groundwater. On the other hand, if a certain radioactive component is not soluble in the acid slurry, it will not be soluble in more neutral groundwater, because the solubility of such components is lower in neutral than in acidic solutions. Such a component will be simply microencapsulated in the phosphate matrix of the CBPC. Thus, the solubility of hazardous and radioactive components is key to chemical immobilization. 

The various case studies discussed in this paper demonstrate that CBPCs are a very versatile material for the stabilization of hazardous and radioactive waste streams. CBPCs chemically immobilize and microencapsulate the contaminants, and reduce leaching to levels that meet WAC at DOE sites. They are also suitable for the macroencapsulation of various contaminated objects. 

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