Multifunctional soil

Below we will consider the critical limits apphed for different purposes in Europe and North America. Examples are given for multifunctional soil and water use, differentiation in land use types and bioconcentration in food web. 

In various countries, critical limits for soil have been derived to assure multifunctional soil use (Table 2). 

An example of using one predicted property to predict another is predicting the adsorption of chemicals in soil. This is usually done by first predicting an octanol water partition coelficient and then using an equation that relates this to soil adsorption. This type of property-property relationship is most reliable for monofunctional compounds. Structure-property relationships, and to a lesser extent group additivity methods, are more reliable for multifunctional compounds than this type of relationship. 

Table 2. Critical limits for heavy metals in soil of various countries, related to multifunctional uses.

In 2002, changes were incorporated in the SPA. The major adjustment was to make remediation cheaper by the introduction of land-use-dependent remediation objectives (LRO Figure 9.3) (BEVER, 1999). Consequently, the multifunctional approach was abandoned. It is no longer necessary that each remediation project should end in soil with contamination levels below the target values. 

After phosphates, silicates are the most ubiquitous builders used in LADD formulations. Like tripolyphosphates, silicates are multifunctional. They are, however, better sequestrants of magnesium ions. A combination of phosphate and silicate is therefore generally used in ADD formulations. In addition to their sequestering properties, silicates provide alkalinity, soil suspension, and anticorrosion properties. A detailed treatment of the synthesis, chemistry, and applications of silicates has been undertaken by Iler [21], Other reviews are also available [22,23],... 

The results showed that the application of the multifunctional method SEKRIOP to clayey soil permitted the simultaneous removal of heavy metals (Pb, Ni) and PAH (phenanthrene) in situ. The removal was observed in all cells including the control cell (Table 15.2). However, the removal percentage [normalized calculations expressed as the final concentration C (mg/kg) to the initial concentration Co (mg/ kg)] varied due to the different response of physicochemical processes, which were different in each cell. 

Considering the effectiveness of the simultaneous heavy metals and PAH removal, it can be concluded that SEKRIOP might be used for an electrokinetic in situ remediation of mixed contaminated soils. The development of the above-described multifunctional method permits remediating the soils, particularly those characterized with low permeability. The results from the research can be applied to various municipal and industrial sites containing petroleum products and heavy metals. 

Nanotechnology has improved the technical properties of fibres in textiles and coatings in such areas as electrical conductivity, magnetic susceptibility, interaction with light, photonics, chemical protection, friction control, abrasion resistance, waste water and oil repellence, soil release and biocompatibility. Tailoring and controlling structures on the nano-scale level is a key factor in the development of advanced materials or structural components in multifunctional applications. Some finishing processes in... 

As a consequence of the multifunctional nature of the sorption parameter recent developments are directed to testing schemes using HPLC with various stationary phases. The basic principle is to determine separately the different interactions involved in sorption on standardized material, and then to recombine the data from the individual measurements for a comprehensive sorption parameterization. Until the experimental sorption data will be determined by a stringently standardized method, and the values refer to a consistently defined endpoint, sorption modelling must remain a formalization of empirical relationships. Accordingly any QSAR approach to soil sorption is principally restricted by the problem of determining precisely which activity is accounted for ... 

Multifunctional Materials. Multifunctional property improvement by binding of specific polymers to fibers and fibrous products has been extensively investigated and reviewed (81). With poly(ethylene glycol) as the bound polymer, functional and aesthetic property improvements include thermal comfort, liquid absorbency/repellancy, increased wear life, soil release, resistance to static charge, antimicrobial activity, and resiliency. Numerous applications such as sportswear/ski wear, protective clothing for health care workers, durable and nondurable hygienic items, work uniforms, and space suits are being commercialized and evaluated. 

Geotextiles are those fabrics used in geotechnical applications, such as road and railway embankments, earth dikes, and coastal protection structures, designed to perform one or more basic functions such as filtration, drainage, separation of soil layers, reinforcement, or stabilisation. Therefore, almost every geotextile application is multifunctional. 

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