A seam of actinolite-asbestos in ophiolitic metabasalt (N Corsica, 2013). © BRGM - Didier Lahondere

Testing a plasma filter for real-time detection of suspended asbestos particles

02.27.2017
The PLASMIANTE project will be testing a plasma cell filter developed by one of the project partners to analyse suspended asbestos dust at asbestos removal worksites. This is a technological breakthrough with the potential to considerably reduce the time and cost constraints of asbestos removal thanks to on-site capture and analysis of asbestos dust.

At present, detecting suspended asbestos dust at the asbestos removal site itself involves a lengthy and costly sampling process. The standard method is to filter the ambient on-site air and count the asbestos fibres using a transmission electron microscope, or TEM-A, which is a long and difficult exercise. An operator then analyses the fibres to determine whether the fibres are nanometric in diameter, their mineral composition and their crystalline structure using an electronic diffraction apparatus. TEM-A is expensive to use and cannot produce results in real time. Currently available automated equipment used for real-time inspections does not produce sufficiently accurate results.

Developing a new and reliable system for asbestos measurements and analysis

Given these problems, development of a new and reliable system to measure, analyse and count asbestos fibres is urgently needed. The most difficult operation is filtering of the asbestos dust, which can then be analysed by infrared spectroscopy, a fairly standard technique.

The project will seek to demonstrate the effectiveness of the plasma filter to sample and identify asbestos dust. The technology has reached Level 5 in terms of maturity, which corresponds to a model validated for a representative environment.

PLASMIANTE will apply the physics of powder plasmas to filter and quantify asbestos dust. © GREMI/ Pr L. Boufendi Univ. of Orléans

A plasma cell system to filter and identify asbestos dust

To overcome the filtering constraints, PLASMIANTE will be testing the Plasma technology developed by the GREMI research group, which works on energy systems in ionised environments. The aim is to apply the knowledge acquired by scientific studies of powder plasmas in order to filter and characterise asbestos in aerosols. The principle is to use the plasma in which the rising nanoparticles are trapped as a filter enabling the detection and measurement of asbestos nanoparticles in ambient air.

The dust captured on site is injected and trapped in the radio-frequency plasma cell. This makes it possible to control the known properties of powder plasmas to filter out nanoparticles according to their form and discrimination by the plasma. Infrared spectroscopy can then be applied to characterise their crystalline structure. For this part of the project, the BRGM is working with Thermo Fisher Scientific, which ahs developed competences for the identification of the three most common types of regulated asbestos fibres (Chrysotile, Amosite and Crocidolite), based on their spectral signature in the infrared. Thermo Fisher Scientific is in charge of coupling the infrared technology with the Plasma cell and validating the technique.

The BRGM has the facilities and capabilities to create a dust-laden environment in which the different type(s) of asbestos can be controlled and the number of fibres per litre of air quantified. It also has the security equipment and certification required to implement experiments involving asbestos fibres. Here, the BRGM acts as an end-user. Its role is to harness its competences and facilities to reconstitute the necessary atmospheres, conduct feasibility validation tests and define prototype performance.

Asbestos removal: the BRGM's PLASMIANTE project wins a PRDA award

The BRGM's project is one of the 11 award-winners under a call for projects issued for the French R&D plan for asbestos removal (PRDA).  The PRDA was launched in 2015 by the Ministry of Housing to provide financial support for innovative asbestos removal projects. The aim is to support activities that promote building renovation and energy efficiency, with a view to the prevention of insurance claims.

The 11 award-winners under the first call for projects will receive a total of €1.4 million in funding. The PLASMIANTE project will receive a grant of €400 000, with the first €200 000 allocated by the scientific committee up to the Go/No-go milestone establishing the concept's validity, and the remaining €200 000 once the project gets the go-ahead. The Chairman of the PRDA, Alain Maugard, stressed that of all the projects examined by the scientific committee, this was the most likely to achieve a breakthrough.

More about the award

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