Remediation of pollutants

This section covers environmental applications of nanomaterials insofar as they are directly applied to the pollutant of interest. The photocatalytic degradation of organic pollutants and remediation of polluted soils and water are discussed here. The high surface areas and photocatalytic activities of semiconductor nanomaterials have attracted many researchers. Semiconductor nanomaterials are commercially available, stable, and relatively nontoxic and cheap. Prominent examples that are discussed are metal oxides such as Ti02 and ZnO and a variety of Fe-based nanomaterials. 

REMEDIATION OF POLLUTED ARID AND SEMI-ARID SOILS... 

Essentially, photocatalyzed reactions have generated considerable interest after the photocatalytic splitting of water on TiO electrodes was first demonstrated by Fujishima and Honda in 1972. Subsequently, various kinds of photocatalysts have been employed for hydrogen production and remediation of pollutants from water. 

In the case studies to follow, both hydrophilic and hydrophobic polyurethanes are used to affect remediation of polluted air and water. We will not discuss conventional wastewater systems because they represent large public works projects that dot the developed world. The first three case studies cover the use of reticulated foam as a scaffold for the remediation of polluted air. Another involves the use of a hydrophilic foam as a scaffold for a biofilter to treat aquaculture wastewater, permitting its return to the system (closing the recycle loop). Lastly, we will review our work on a composite of hydrophilic polyurethane grafted onto a reticulated foam to treat VOC-contaminated air. 

Gianfreda, L., and Rao, M. A. (2004). Potential of extracellular enzymes in remediation of polluted soils a review. Enzyme Microb. Technol. 35, 339-354. 

Monitoring and remediation of polluted sediment should be an important task in the implementation of the Stockholm Convention in China. 

Bringas, E., San Roman, M.F. and Ortiz, I. (2006) Separation and recovery of anionic pollutants by the emulsion pertraction technology. Remediation of polluted... 

RuUcens, W.H., Tichy, R., and Grotenhuis, J.T.C. 1998. Remediation of polluted soil and sediment Perspectives and failures. Water Science and Technology, 37 27-35. 

A. Garca-Sanchez, A. Alastuey, and X. Querol, Heavy Metal Adsorption by Different Minerals Application to the Remediation of Polluted Soils, The Science of the Total Environment, 242(1), 179-188 (1999). 

Boisson, J., Ruttens, A., Mench, M., and Vangronsveld, J. (1999). Evaluation of hydroxyapatite as a metal immobilizing soil additive for the remediation of polluted soils, 1 Influence of hydroxyapatite on metal exchangeability in soil, plant growth and plant metal accumulation. Environ. Pollut. 104, 225-233. 

PCBs are extremely stable to heat, chemical, and biological decomposition. They are excellent insulating and cooling fluids, extensively used for many years in manufacture of transformers and capacitors. PCBs are also used in hydraulic fluids, lubricating oils, paints, adhesive resins, inks, fire retardants, wax extenders, and numerous other products. The chemical and physical properties of PCBs make the remediation of polluted sites difficult. They resist degradation and absorb into soils and colloidal materials in water. Some persist with half-lives of 8-15 years in the environmental compartments. This stability contributes to their dispersion in the environment and long-range air pollution. Because they are lipophilic, these species are stored in fatty tissues and accumulate in the food webs (see Section 2.2). 

Electrodialysis is also effective in remediation of pollution by heavy metal ions, and recovery of valuable materials from the waste. Water containing heavy metal ions such as the waste solution and effluent from galvanizing plating baths can be... 

The purpose of this book is to provide the state of the art on electrochemical remediation of polluted soils, sediments, and groundwater. Specifically, an... 

Overall, the field applications demonstrate that the electrokinetic treatment is an adequate tool for the remediation of polluted sites with heavy metals. However,... 

Pazos M, Ricart MT, Sanroman MA, Cameselle C. (2007). Enhanced electrokinetic remediation of polluted kaolinite with an azo dye. Electrochimica Acta 52(10) 3393-3398. 

An alternative for containment of source areas and remediation of polluted ground-water plumes is to deploy an EBIS . An EBIS avoids the necessity to pump and treat hundreds of thousands of cubic meters of groundwater, which is only slightly contaminated. It also means that the groundwater flow regime is not influenced. 

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