Na-activated bentonites and natural zeolites, new organophilic bentonites, inorgano-organophilic bentonites, new synthetic zeolites produced from perlite fines and de-aluminized zeolites were developed and tested for their ability to retain toxic inorganic and organic compounds produced by human activities and frequently found in landfill sites. The experiments were carried out in both laboratory and pilot plant scale including prototype horizontal and vertical landfill barriers in both Germany and the U.K.
The experimental results showed that the new synthetic materials and modified natural products are capable of adsorbing almost all toxic compounds tested in both the laboratory and the pilot plant scale. These materials can be added in small amounts, both separately and in mixtures with each other, in the soil matrix in order to improve its retention capacity without increasing its permeability. It was also found that the formation of synthetic zeolites might be followed by synthesis of new high added value zeolite-A and zeolite-X, which could be used as detergents or/and molecular sieves. Finally it has been shown that environmental application of these materials, at least in the case of small projects, might be plausible, because it would not increase their cost.
The proposed project is aiming at the development of new high-added value products based on bentonite and zeolites for environmental protection applications. Three main fields of application of the newly developed products make up the goal of the project:
a)Waste deposit barriers (horizontal barriers against organic and inorganic toxic leachates from mining, metallurgical and municipal sanitary and hazardous waste deposits)
b) Trench wall slurry-technology (vertical barriers against orgnic and inorganic toxic leachates from contaminated industrial sites as well as already existing waste deposits which are not encapsulated according to modern technical standards)
c)Grouting technology (injection of the developed products into soil or rock skeletons in order to improve the imperviousness and retention properties against toxic agents).
The project will involve the following steps in gaining the research tasks: 1.Selection and characterisation of suitable bentonite, zeolite deposits. 2.Application of innovative treatment processes, in order to adjust or improve their selectivity in terms of inorganoorgano affinity using reactions with inorganic cations organic chain structures, etc. The development of new organophilic, inorgano-organo bentonites, new zeolites from perlite fines (not marketable "wastes") and modified natural zeolites is the aim of this research step. 3.Study of the complex physicochemical interactions of the new products with specific soil and rock environments 4.Field application in waste disposal barriers and slurry trench walls in the scale of test fields.
Successful completion of the project will result in the development of new products with enchanced value, as well as the in the development of novel hazardous tailings encapsulation/treatment technisques with a positive impacts on environmental protection.
Funding SchemeCSC - Cost-sharing contracts
TN23 1PP Ashford