Pollution control technologies: physical and chemical processes (civil environments and workplaces)

Working Group
Maria Letizia Ruello, Chiara Giosuè, Mattia Pierpaoli, Silvia Palmieri, Luca Riderelli
The need to limit the concentration of airborne pollutants often involves the use of various control systems; systems that are almost indispensable component of the industrial activities that emitt airborne pollutants in large quantities. Even in the civil, the presence of high concentrations of pollutants in urban, and the air quality requirements imply abatement strategies.

The best technologies for industrial emissions control are identified by choosing preferably processes that allow recovery and recycling, such as adsorption on solids or specific textile filters or electrostatic precipitators, depending on their specific convenience.The sizing of the filtering plants and the performance avaluation are investigated.

In the civil, one of the most promising innovation for the reduction of pollutants is the introduction of photocatalysts materials (such as titanium dioxide TiO2) in building materials and finishing.

An exploitation of these compounds is the development of new materials with self-cleaning properties. In this case, the photocatalyst admixture for cementitious materials or finishing promotes oxidative decomposition of the organic materials that are deposited on the treated surfaces. The oxidation process mediated by these catalysts is promoted by the light, and possible applications are developed for the external surfaces of buildings or other architectural artifacts.

The reduction efficiency of the developed materials and their environmental performance are investigated. In the laboratory tests it is important to operate in reproducible and controlled conditions and comparable as possible with the real ones. The test chambers are constructed with materials that exhibit minimal adsorption properties of the volatile compounds under investigation, and are supplied with high purity air to minimize the background noise. The test chambers are kept at controlled temperature, humidity and air mixing parameters.

Qualitative and quantitative performance of the investigated material are determined by analysing the composition of the air inside the test chamber and calculating the flux of pollutant deposition (ng m2 s-1) in relation to the velocity of deposition (m s-1) and its concentration (ng m3).